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Mikes Z car

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  1. Mikes Z car

    Turn switch relay mod

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    Hi all,
    I added relays to the turn switch to take the current load off the switch by copying the idea on the website below. The mod is reversible and by doing so will leave only hidden soldered wires inside the clamshell as the only evidence it was done unless holes were drilled to mount the relays. With this setup the heavy current still flows through the fusebox but only a small current flows through the turn switch itself. I followed this website posting but I used a different brand of relays and added a connector strip; I am grateful for the information:
    240Z Turn Signal Switch Circuit Modification
    The link above is to the article contributed by: Peter Paraska
    As in the article I took the switch apart to scrape clean the contacts though I also sprayed all contacts with deoxit contact preserver. IMO an easy alternative to relays is to clean the contacts only and not install relays; the switch with cleaned contacts should last quite a while. I went with relays because my DD uses them, it is an 83 model and has never had a light switch problem.
    Inside the turn switch I soldered the rivet where it makes electrical connection as the fuse box uses similar rivets. This was done in case I return the circuit to stock, this soldered connection isn't used with relays:

    Turn signal switch in action, ball bearing not shown (click for animation):

    I have read that newer cars have one contact on each side of the "see saw" where my switch has two. I ran fine sandpaper through the two upright springy contacts being careful not to bend them back too far so I wouldn't permanently bend them however these two contacts are not used for heavy current with the relays installed. I had read that others had taken the similarly constructed headlight switch apart more than once and sometimes the tabs that hold the switch circuit board in place break off if they are bent too many times. To avoid that I bent the two corners of the smaller curved metal side of the turn switch cover out as the corners only have to bend at a small angle before the tab releases the switch circuit board thereby reducing metal fatigue. I used channel locks to squeeze the switch cover back together during reassembly as a parallel force in line with each side prevented twisting of the cover. Note that IMO it is easier to get the bearing back in if the switch is taken apart by bending the tabs rather than what I did as the reassembling parts approach each other straight on then.

    Ball bearing:

    I added a Radio Shack white strip connector to make it easy to troubleshoot/correct any wiring errors if needed. Schematic and picture of my adaption of Peter's circuit:

    Note that on the back of my turn switch circuit board I soldered together the white Red and Green Black wires to improve reliability as this puts two contacts in parallel. If one contact should fail the other will likely still do the job. I did the same with the White Black and Green Red wires on the turn switch for the right turn relay. Newer turn signal switches have one wire where mine has these two I understand.
    Relay mounting- works, but I may not leave it like this:

    The relays I used are the same kind described in the article, two triple pole double throw relays, but they are a different brand. Peter used a radio shack relay, part number 702012. Note that a relay rated for 15A at 240VAC isn't the same as a relay rated for 15A at DC. The DC current rating is what is important here as generally relays can handle more AC current than DC. To make sure I don't forget how to revert to stock wiring I printed a copy of the schematic and the picture of the wiring layout above and taped them to the inside of the clamshell.
    Mike
    ****************************************************
    This may or may not be obvious but triple pole relays are not the only option for this mod. Other relay configurations will work depending on your creativity. One possibility would be to use 6 single pole double throw relays. Each triple pole relay could be replaced by three single pole double throw relays with the three coils wired in parallel. My feeling is that triple pole relays are easier to wire because of how I think about the wiring process but someone else might work fine with another relay configuration.
  2. Mikes Z car

    Cowl leaf screen

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    This mod is reversible leaving no trace. Using silicone rubber sealant I glued a piece of aluminum window screen I spray painted black onto the bottom of the cowl where the holes are to keep leaves and other debris out. The screen helps prevent corrosion from debris trapping moisture in the area where the windshield wiper motor is.
    Mike
    Looking at bottom of cowl, screen being glued on:

  3. Mikes Z car

    Clock replacement for 240Z (Quartz)

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    Hi all,
    I got a quartz clock from Michael's (arts and craft store in USA) and replaced the mechanical clock mechanism in my 1970 240Z (my clock face says JECO). There is a thread where someone else used this same clock for their Z, the following is my experience. The easiest way to do this IMO is to use the hands from the new clock and to wrap wires onto the new clock battery connections to remote the battery location to perhaps the fuse box. I didn't install that way as I wanted the clock hands to look stock and I prefer soldered connections.
    Materials needed:
    A Quartz clock from Michael's ($18), see pictures of clock card for model
    B Battery holder for AA (or AAA) battery from Radio Shack
    C Small wire to run from clock to battery holder
    D Epoxy glue
    E Glue gun to put a dab of glue on inside of set time knob
    F Optional tape to cover three bolt holes in back to keep light in
    G Bench grinder, dremel or possibly sand paper (to remove raised edges on back of clock face and hour hand)
    H Soldering gun if soldering connections
    1. I ran the new clock for 24 hours verifying accuracy. Michael's clock front bezel and final result:
    Bezel (not used):___Final result:

    Clock card from Michael's:

    The existing clock can be taken out through the heater fascia panel or glove box. Thread on removal:
    http://www.classiczcars.com/forums/help-me/46462-new-clock.html?highlight=liner
    Also see clock threads listed below. I went through the heater panel as it was already open for other work. Per these clock threads some 240Z clocks have a bracket for mounting, mine doesn't seem to have a bracket. My clock was held on with an 8MM bolt that is also a phillips head. I had to use a nut driver for more leverage.

    2. On back of the clock I removed the three small nuts. I also removed the 2 screws that hold the two clock halves together. I cut the wires for the motor off the back of the clock.
    3. I pulled off the Z clock hands but had to gently use a small screwdriver from the side to persuade them to come off. Screwdrivers can be covered with tape to prevent scratches. Inadvertent scratches can be marked out with a black marks a lot.
    4. I covered the 240Z clock face with a ziploc bag I cut a slit in to go around the center hole by taping it on both sides of the thin aluminum face to protect it though thin cardboard might have been better protection however I didn't damage anything. I did not tape directly to the front of the clock face to avoid marks. After removing the hour hand from the 240Z clock to prepare it for re-use I taped the front of it to a piece of cardboard to expose the raised edge to discourage it from taking off while using the bench grinder on it. I ground the raised edge flush on the back of the face and the back of the hour hand. The minute hand didn't need modification.
    Front view:............................Raised edges on back to be ground off:

    5. I epoxied the new clock movement around its edges onto the back of the face making sure to get the post for the hands centered in the hole on the face. Epoxy wanted to let the new movement slide out of position so I re-centered it a few times as it dried.
    6. I wanted to re-use the 240Z hands but they have mounting holes that are too big to fit tightly on the new movement so I epoxied the 240Z clock hands on top of the hands on the new movement from Michael's. To make that possible I cut off about 1/4 inch of the minute hand on the new movement as it was too long and would have been been seen sticking out from under the end of the stock 240Z minute hand.

    On both hands on the new movement I ground off part of the sides of the arrow on the ends of the hands as they were wider than the width of the 240Z hands and again would have been visible once the clock was placed into operation. I had to be careful here as the new hands are thin aluminum.
    7. For the battery connection I could have wrapped wires onto the existing battery holder which would have been much easier than what I did. An idea here would be to wedge the wires in the battery compartment with a wooden dowel cut to the size of an AAA battery and maybe glued in. Another idea might be to solder the wires to a small piece of flat copper with the flat copper wedged in between the battery connections and the wooden dowel. See * below for how I did the connection to the circuit board.
    8. I pressed on the hour hand from the new movement that had been prepared to be physically smaller so it would hide under the 240Z hour hand. Next I epoxied the 240Z hour hand that had had the raised edge removed on top of it. The edge would have raised the hour hand to a height to where it would not have cleared the minute hand I was about to install. The 240Z hour hand wanted to slide off center so I had to recheck it periodically as the glue dried. Five minute epoxy might have worked better.
    9. To install the minute hand from the new movement I put it over the already glued on hour hand to check for clearance, I needed to bend the minute hand up and over the hour hand assembly using tweezers for the bending. I applied epoxy to the 240Z minute hand with a toothpick to make sure I didn't get too much that might flow into the second hand mount point (not used) in the center of the new clock post to avoid having it bind. After gluing the stock 240Z minute hand I had to recheck it periodically as the epoxy was setting to check for centering and to make sure it was sitting flat with respect to the face. I put a toothpick across and on top of the minute hand at the post it was on with a small weight on the toothpick with a spoon to hold up one end of the toothpick with the idea of keeping the minute hand flat and centered on the post so it would look right.
    10. For the time setting function I put a small dab of glue gun glue on the end of the set knob next to the minute hand (a thread mentions using a glue gun). This was to make the set knob reach further when pushed in to contact the 240Z minute hand that was glued on top of the new movement minute hand. I made sure to get the glue down in the slot at the end of the setting knob to secure the glue better. Too much glue can be trimmed with an ordinary finger nail clipper. I think the end of the glue dab needs to be fairly flat. Not enough glue and the set knob when pushed in won't contact the minute hand making setting the time impossible, too much glue and the knob will bind the minute hand possibly stopping operation of the clock. One other thing I did to further secure the glue dab was to take a toothpick and apply a very tiny amount of epoxy to the junction between the dab and the set knob. I used jeweler's magnifying glasses to make sure I didn't glue the set knob so it wouldn't push in.
    11. The end result is that the clock looks great installed in the car and is keeping good time.
    Here are threads on fixing Z clocks:
    Zclocks good quality:
    http://www.classiczcars.com/forums/thread5093.html
    Keep hands from new clock:
    http://www.classiczcars.com/forums/open-zcar-discussion/48910-clock-redo.html
    Getting clock out thru glove box (tends to destroy glove box) or heater panel:
    http://www.classiczcars.com/forums/thread9492.html
    Different kinds of clocks described-motor type-pendulum type:
    http://www.classiczcars.com/forums/thread18442.html
    Fixing electric circuit type clocks:
    http://www.classiczcars.com/forums/thread22795.html
    Replace with desktop auto car parts store clock -orange face:
    http://www.classiczcars.com/forums/thread36393.html
    Replacing capacitors on clocks that use them sometimes helps:
    http://www.classiczcars.com/forums/thread18851.html
    Zclocks and Auto Meter clocks discussed:
    http://www.classiczcars.com/forums/thread13723.html
    Clock runs when car runs but then quits a few days after car is parked:
    http://www.classiczcars.com/forums/thread12992.html
    Changing out mechanical movement to quartz discussed, radio shack 12 volt to 1.5 volt regulator mentioned:
    http://www.classiczcars.com/forums/thread10767.html
    Oiling original mechanical clock sometimes works sometimes doesn't:
    http://www.classiczcars.com/forums/thread7817.html
    * I tried to solder to the connections in the battery holder but the solder would not stick. To solder directly to the circuit board I took the movement apart by unscrewing a screw and unsnapping the two plastic latches on the sides. I soldered the new battery wires directly to the circuit board where the existing battery holder connects VIA a spring like action by two prongs (The prongs aren't soldered). I scraped off the two circuit board "pads" with a pocket knife where the two springlike prongs connected and got down to a copper colored metal which my solder gun could solder to. The wires I used are very small 30 gauge, they need to be to make for easy soldering to the small pads and to make it easy to get them to pass out of the movement though a small hole could be drilled in the plastic case of the movement for the wires. I personally feel taking the movement apart and getting it back together properly was not particularly easy as there were several very small plastic gears that kept falling off and I had to remember where they went.
    Clock innards:

    12. **** How to get rid of the AA battery: ****
    Schematics below include the 320 ohm resistor needed for quartz clock per spec sheet for minimum load of 4 mA. Be sure to adjust the 5K pot for 1.5V out before connecting clock.

  4. Mikes Z car
    This is the original fascia nut and odd looking squarish washer that came out with it:

    One of the captive nuts on the fascia on my car was stripped out so to fix that I made my own captive nut by cutting a rectangle shape out of a repair metal from Thrifty hardware and drilling and tapping it for the 4MM original machine screw. I used a bench grinder to make the new nut have the same size as the original and to have the beveled edges the original has.
    The existing machine screw size is 4 MM and according to my drill and tap sheet the drill size to use for tapping is 1/8" (or 3.3MM) which worked well. The fascia nuts I had were stripped out bad enough that I could not be sure what the pitch was so I won't list that to avoid posting inaccurate info.
    The existing captive nut can be easily removed by prying open the two metal retainer strips that are in front of and in back of the nut that hold it captive. I had to use care to pry the strips just far enough so that the stripped nut was removable as otherwise the new nut would want to fall out if the strips were sprung out.
  5. Mikes Z car

    Heater blower motor squeal stop

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    It is possible to lubricate both blower motor bearings without taking the motor out of the car to stop squeals or other noises related to motor bearings. I realized this after I had taken the motor out to lubricate the bearings. Many have opted to replace the existing blower motor and fan with a Honda civic heater fan. I like to fix things so I oiled the old motor because it was turning slowly and was squealing.

    Oiling both bearings with the fan in place in the car can be done by taking the end cover plate off of the motor keeping an eye out for the 4 washers that may be on the motor shaft.
    There were four on my 1/1970 car with one of the middle ones being a red fiber washer I imagine to reduce mechanical noise transmitted to the motor housing. The washers can stick to the end plate when it is removed and then drop off if they aren't noticed. The rear bearing is easy to lubricate with a light lithium grease or other suitable lubricant as it is a part of the end plate. The front bearing is easily accessed for lubrication with an old fashioned oiler that squirts oil or possibly by using WD-40 with its spray straw. WD-40 is explosive so if it is used a good airing out of the motor before reassembly might be a good idea. There are two magnets in the motor with a gap near the top of the motor between them of maybe 1/2 inch. An oil can with a long nozzle that squirts can be inserted in this gap to squirt oil up to the front bearing. WD 40 could also be used by inserting the straw that comes taped to the can in the same gap between the magnets that an oiler would use. The top gap would be preferred for the oiling as the oil can flow down to the bearing though the bottom gap can be used. When replacing the motor end cap be sure the tang gets aligned with the rubber grommet for the wires. If this isn't done the motor end cap can be installed 180 degrees out from the proper position resulting in it being slightly cocked over at an angle due to the tang sticking out which would not be good for bearing alignment with the motor shaft.
    Rear bearing can be seen here:

    Since I had already taken the motor out of the car to oil the front bearing I sat it on a workbench with the fan side down and poured motor oil into the gap between the magnets knowing it would flow down to the front bearing. I could not get the fan off and remember reading a thread where someone else ran into the same thing though your situation might be different.
  6. Mikes Z car

    Glove box liner- make your own

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    This describes how I made a two part glove box liner for a 240Z using 3/16" thick foam board.
    The two parts make it easy to install:

    Replacement glove box liners are available from classiczcars.com vendors however I like making things so I thought I would fabricate a new liner. I considered making this out of metal but my metal working skills are not that good so I thought I would use an easier to work with cardboard like material. After I made the liner I cut it in half 3 1/2" from the left side as it would be seen installed in the car to make it easy to install (or remove later). I took the old liner out to work on the heater fan and to run speaker wiring but broke it getting it out. I like originality but wanted something easier to work with. I still have the original liner that has been repaired if needed for some reason later.
    Two part liner separated:

    Two part liner pushed together:

    Installing two-part liner-
    Step 1:

    Step 2:

    Step 3:

    Step 4:

    Installed:

    The 3/16" foam board I used for the liner was available at a craft store and a dollar store. It has an open cell foam core sandwiched between poster board. It is strong and resilient, much stronger and more flexible than the 40 year old original posterboard liner. I copied the liner from a 1/1972 liner I had on hand after I took it apart, flattened it out and drew lines around it on the foam board. I also took pictures of the original liner under a sheet of glass to flatten it out laid on fabric board with one inch lines going both ways to allow duplication by someone else. The color is reversed in the pictures to make the patterns easier to see. Lines can be drawn 1 inch apart going both ways on the foam board with a white pencil and a long straight edge. By referring to the patterns in the pictures the patterns can be duplicated on the foam board. Both pictures below are looking at the outside of the liner.
    Side and angled top patterns:...........................Main pattern (both patterns from a 1/1972 car):

    To make the folds I pushed a wide putty knife blade into the cardboard on a hard surface where the folds are needed as indicated in the pictures.
    Pattern identification:

    I used a spring loaded power hand stapler to staple the parts together at the folded over tabs in the same places as the original liner. I bent each staple over on the inside with needle nose pliers afterwards though glue could have been used instead to fit the parts together using magnets to temporarily hold parts together. It may be necessary to trim the two halves where they meet to get them to fit into the car, I had to trim about 1/2" off of this middle edge with scissors after I made the liner because the original liner material was thinner than what I used. The four speed nuts needed for the sides at the top I found at an auto parts store though they might also be found at a hardware store if they are not on an original liner you already have.
    *****************************************************
    I actually made three of these liners, the third one that is in the car now is described above. The 1st one was made out of ordinary cardboard and while sufficiently sturdy for normal use I had tried to copy the original without taking it apart which introduced errors in the shape. Note that the car has steel support under the bottom of the glove box for the first three inches from the glove box door all the way across making the area near the door very strong no matter what material I might have used. The second liner was constructed from thin white cardboard and was made from the pattern in the pictures above. It fit together and in the car well but I went with foam board as it is even sturdier.
    For reference, here is a difference between glove box liners for a 1/1970 car and a 1/1972 car (and repair notes). I copied the 72 liner because I figured it would work in both the 1970 car I have and in later models (the drawing layouts above are for the 1/1972 car):

  7. Mikes Z car

    Rear frame rail interiors anti rust spray

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    Hi all,
    I sprayed all interior channels of the rear frame rails and interior of wheel wells of a 240Z with two cans of Transtar amber anti corrosion material using existing holes where possible. The front frame rails are more likely to rust but I had already sprayed the interior of the front rails on my car. A thread describing how I did the front frame rails is here:
    http://www.classiczcars.com/forums/body-paint-s30/40048-two-frame-rails-tc-rod-there-floor-between-them.html
    The Transtar amber anti corrosion material I used is described on another blog here:
    Hatch anti corrosion interior passageways - Blogs - Classic Zcar Club
    240Z rear frame naming convention I used (is there some standard for this?):

    Preparation of the four crossmembers:
    1. Front two crossmembers- I had to drill two 5/16" (or 8 mm) holes behind the seats on the floor, one behind each seat to access the two crossmembers right behind the seats (what I am calling front crossmembers). Right side -passenger side in U.S. shown -other side prepared in the same way:

    These two holes could have been made under the car to avoid having holes in the floor behind the seats.
    2. Middle crossmember- I had to enlarge an existing slot at the bottom of one of the shock tower braces on the floor with a large screwdriver to allow access to the interior of what I am calling the middle crossmember. Only one slot needed bending to access most of this crossmember, that one slot can be bent back later if desired, I left it bent open for possible future sprayings since it won't show when I put the shock tower vinyl back down:

    I also enlarged a slot on the floor inside the tower braces on both sides of the car to gain access to a two inch long portion of the middle crossmember on both ends of it. The slot I used is closest to the back of the car inside the brace, see the two drawings immediately below for further clarification. This step possibly could have been skipped but I like to spray everything. These two enlarged slots will never be visible in the car.

    Total of two slots INSIDE the braces were enlarged, one slot on each side.
    >>

    3. Rear crossmember- Removed rear plastic interior side panel finishers (not my car- thanks to whoever has this car):

    Spraying operation (tip- cover spray nozzle and top of can with a ziploc bag when spraying as wand tends to pop off can sometimes- prevents getting Transtar on your car or hand):
    4. Front crossmember right side (both sides done the same way):
    Spraying inboard from access hole

    Spraying other direction, toward side of car

    5. Middle crossmember:
    I sprayed the middle crossmember by inserting the wand into the slot I enlarged slightly with a screwdriver. See step 16 below for more info. I also sprayed inside the last two inches of this crossmember on both sides of the car by inserting the wand into an enlarged slot inside each tower brace. See step 2 above for more info.
    Top of picture is towards front of car.

    6. Rear crossmember (spraying towards middle of car from both sides):
    Right side

    Left side

    7. Frame rail right side (left frame rail was sprayed in the same way):
    Spraying forward from access hole

    Spraying toward back of car

    8. This drawing shows drilled holes location, one of the slots that needed prying open a bit and access for rear crossmember. It does not show the tower brace slots inside the brace that I enlarged for that detail see last two drawings in step 2 above.:

    9. Existing holes and "walls" in the rear frame (I used the front four existing holes for spraying both frame rails at the sides of the car, vinyl on shock tower was peeled back for access to middle holes):

    Preparation details:
    10. For spraying the two front crossmembers behind seats on the floor I drilled a 5/16 inch hole (8 mm also would have worked) in line with an existing hole in frame rails and 40mm from the front edge of the existing frame rail hole. A 5/16" (or 8mm) hole is just large enough to allow the transtar wand with its 360 degree brass spray head to fit through.
    11. I pried open the floor sheetmetal slot a bit at the shock tower brace bottom by twisting slightly with a large screwdriver to give access for spraying the center crossmember.
    I also pried open the floor sheet metal hidden inside the brace itself to access a two inch long closed off area on both ends of the middle crossmember. Although I did this someone else might want to skip it.
    12. I removed the side finisher panels immediately in front of the tail light finisher panel to gain access to the rear most crossmember.
    13. I peeled the vinyl up from the floor on the shock tower braces to allow access to an existing hole in the floor to spray the inside of the side frame rails.
    14. I poked a hole in the bottom of a trash bag and taped the hole in the bag around the holes I would be spraying into to prevent getting spray on the interior of the car should a wand be pulled too far out of a hole while spraying is in progress.
    Notes:
    15. The Transtar plastic spray wand can get kinked when spraying the side frame rails forward of the rear wheels. I actually broke an old wand practicing for the actual spraying and realized the frame rails that go forward and down from the shock towers make two turns, kinda tough on the stiff plastic wand. To minimize the chance of breaking a wand I inserted it gently until it met resistance at the second turn a few inches from the front crossmembers. I pulled the wand out and then inserted it into the existing hole behind the front crossmembers to spray the bottom part of the side rails just behind the seats. This existing hole is 40mm towards the back of the car from the two holes I drilled for the front crossmember. This bottom part of the side frame rails behind the seats is only about 4 inches long so after the wand goes in about 4 inches there will be felt resistance as it tries to turn up towards the shock tower. As soon as I felt that resistance I stopped inserting the wand as I had already done the portion of the frame rail the wand was trying to turn up into from the shock tower hole.
    16. The center crossmember didn't want to let the wand go through the bent slot more than a few inches at first with the spray head on it so I used a wand with no spray head that used to come with the spray wand set from Transtar. The wand set I bought 26 Mar 2014 did not have a white third wand with no spray head however a brass spray head could have been cut off the 2nd wand that came with this recently purchased wand set and that headless wand used then. I used the old headless wand I had from the earlier wand kit purchase. I finally did get the wand with the 360 degree brass head to insert the full length of this middle crossmember, I just had to gently keep trying by trying different entry angles and by gently twisting the wand back and forth. Didn't want to kink the wand with brute force.
    17. There is a blockage in the rear most crossmember in the middle that is maybe 6 inches long. To get around that I used a headless wand as that is skinny enough to go through the blockage and followed up with a wand with the brass 360 degree head on both side inserting it gently as far as it would go. The 360 degree head has a spray that sprays forward as well as spray towards the sides so the coverage is more than 360 degrees.
    18. I made a mess, this project is a great job for the street as the Z frame has many joints for the Transtar spray to flow out of before it becomes waxy non moving anti corrosion material.
    ********************************************
    While I was at it department - (sung to the tune of that old Beatle's song "I should have known better"):
    I also sprayed the interior of the wheel wells since they tend to rust and were accessible with the finisher panels out. After that since I had some Cosmoline handy I painted with a brush all metal I could reach including hidden areas not covered with transtar material. The Cosmoline I have is fairly thick and would not have flowed into the seam the way the freely flowing Transtar material did so I used the Transtar material first on the seam followed up by Cosmoline painted everywhere behind the finisher panel. If I had had no Cosmoline handy I could have dipped a brush into the Transtar spray by spraying the transtar on the bottom of the wheel well first.
    Left side of car wheel well. Right side done the same way.

  8. Mikes Z car

    Firewall insulation pattern for 1/1972 240Z

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    Here are pictures of the firewall insulation of a 1/1972 240Z on a "fabric board" with lines 1 inch apart going both ways to allow duplication if for some reason someone wanted to. Note that the top edge of all three pieces of the insulation are lined up with a blue line on the fabric board. Pictures were taken in full sun and have shadows. To clarify where the black insulation poster board ends and the shadow begins white dashed lines have been drawn. This could be printed out and the blue fabric board lines drawn as white lines with a ruler to extend what is on the fabric board across the black insulation to make duplication easier. Or start with a fabric board (cheap, can get in fabric shops) drawing what you see here on the cardboard fabric board as a pattern.
    The insulation pieces are from a 1972 January MFR date 240Z they didn't come from the car shown in my signature.
    Driver's firewall insulation:

    Passenger's firewall insulation:

    In car- driver and middle sections:

    In car- passenger side:

  9. Mikes Z car

    Throttle jerk fix

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    Hi all,
    This mod eliminates MOST of the throttle jerk but not ALL of it. I owned the car for 4 years before I noticed it still has a small amount of throttle jerk. The previous owner of my 240Z reduced throttle jerk from idle to take off by bending the upper arm of the "turnstyle" as seen in the attached pictures to a stair step shape effectively shortening it. This mod is no cost, possibly reversible and requires no welding, drilling or adding parts. The connecting rod with a nylon ball on both ends connecting between the turnstyle and the carb control shaft arm may not need adjusting or modifying as the new turnstyle connecting point for the nylon ball is both closer in one plane and further away in another which appear to cancel each other out. The PO for my car did this mod however the connecting rod on my car does not appear to have been modified. The first picture shows measurements of the bend in the upper turnstyle arm. The measurements on the ends of the arm are from the center of the pivot to the first bend and from the other end it is from the center of the nylon ball to the first bend from that end. This mod eases the throttle jerk by reducing "mechanical advantage". The carb butterfly opening is slower as the gas pedal is first depressed off idle compared to the stock arrangement.
    To the PO who did this throttle fix a tip of the hat and a moment of silence as I am aware he has passed on.
    Mike
    Measurements:

    Side view:

    Overhead view:

  10. Mikes Z car
    Hi all,
    This has been done before by others, the following is my experience. I added a second hood release cable so now I have two of them in case the original cable breaks. Getting the hood open after the cable breaks is not particularly easy in my view of how others have done this. The easiest way to do this IMO is to do what someone else did, loop a steel wire through where the original hood release cable attaches to the latch under the hood, run it through the firewall grommet for the speedo and make a loop in the end inside the car. I didn't do it that way as I wanted to use a spring sheath pull cable like the original with a knob on the end hidden above the existing hood release handle.
    Materials needed:
    A. 5 foot long pull cable from auto parts store, eBay etc
    B. Wire cutters if desired, to shorten "spring like" sheath and center steel wire.
    C. Needle nose pliers for wrapping steel center wire around hood pull point
    D. Clear packing tape used to slide new cable through hood release firewall
    grommet using existing cable as a pull tape.
    The new cable was pulled through the same firewall grommet the original hood release uses to make it look like it belongs there, painting it black would also help. An easy way to pull the new cable through the grommet is to use slippery clear packing tape to tape the new cable to the old one and then use the old one to pull the new one through the grommet. This has to be after the old one is unfastened from the hood latch connect point so it can be partially pulled back inside the car. Don't use duct tape! That stuff will never go through the grommet unless there is a big hole in it. I shortened the spring like cable sheath to be the same length as the existing cable so it would lie next to it all the way to the latch assembly to hide it. An idea to shorten the sheath would be to pull on the knob to pull the solid center wire out of the way before cutting the spring like sheath (NOW I think of it). I did this the hard way, I carefully used wire cutters while the center wire was still there. The easiest way is to skip this and let the extra cable loop in the engine compartment avoiding the carb linkage or anything else that moves. I clamped the new and old cables together 10" from the hood latch though it wasn't clear to me that a clamp was needed. I tried clamping them together at the hood latch and that didn't work; too much friction for the return spring. I made a clamp out of a small piece of sheet metal about 2"X1" that I clamped around the cable pulls with vice grips. Another idea might be to use a very small hose clamp with a rectangular piece of solid metal held between the two cables, otherwise the cables are too small for most hose clamps. The pull knob for the new cable is right above the handle for the original to keep it invisible until it might be needed. It has a spring holding it up out of sight and is zip tied to the original cable closer to the firewall to keep it from flopping around. I was driving with the hood ajar before adding a backup hood release but the new cable works great and I now get to drive with the hood closed.
    Inside car:________________________Spring to hold new knob up out of sight:

    Hood latch:

    ***** Fixing stripped threads on handle mount*****
    I may be the only one who has had this problem but, the threads the chrome colored nut under the pull handle screws onto on my car were stripped when I bought the car. This nut secures the handle pull to the frame of the car. The loose nut allowed the handle to flop around which I didn't like. The threads (10MM, pitch=1) were too far gone to be fixed by chasing them with a die. A new cable was going for $75 so to fix the loose handle I used two washers about 1 inch in diameter, one chrome and one ordinary steel both with large center holes in them. The chrome washer was used under the pull handle to improve appearance and is slightly larger than the steel washer, all hardware came from Thrifty (Ace) hardware. Two tiny pilot holes were drilled in the chrome washer in line with where two holes were going to be drilled in the steel washer with 3/4" self tapping screws. The steel washer was cut through on one side with a bench grinder (could use a hacksaw) to allow the washer to fit over the cable behind the handle mount. Further enlargement of this cut was done with an ordinary file. The drilled holes in the chrome washer were made a little larger than the self tapping screws I used to drill into the steel washer to allow alignment. Note that the screws have to clear the flange on the back of the cable mount; mine didn't entirely clear the flange so to fix this I used a file to grind off the side of the flange to get it out of the way. The steel washer was placed behind the handle mount, the chrome put in front and the self tapping screws securely hold the two together. Although this violates a prime directive of not drilling holes in the car they are only visible with the door open. Also, the drilled part can be easily replaced as it is attached to the car with two screws. The handle is very secure now.
    Front exploded view:_________________Side view showing stripped threads:

    Back view:

    Picture of install:

  11. Mikes Z car

    240Z frame drawing sketchup

    · %s · %s

    Updated 30 Mar 2014:
    Screenshots:
    Rotating view (click to zoom in):

    Front frame rails:

    Rear frame rails looking towards front of car:

    Sketchup drawing for download:
    240Z frame rails whole car 20 Mar 2014.skp.zip
    Sketchup drawing viewer can be downloaded here:
    Download | SketchUp
    Revision history:
    2013 Dec- Updated drawing includes holes I noticed in the frame behind the seats. (Holes are now in correct location if you happened to have viewed this drawing the first couple of weeks in November)

    There are a total of four holes added to this drawing from the original, two behind each seat. They are in the same location on the floor on a 1/1970 car and on a 1/1972 car where I have seen them. The two holes behind the drivers side seat are in line with each other vertically so that with the plugs out you can look straight down from inside the car and see the street. Same situation for passenger side, trying for clarity here. The holes are 20 mm in diameter. The holes are in the middle of the frame rail that heads back and up towards the floor beside the shock towers.
    2014 March 30- Updated drawing to correct the diameter of rear frame holes next to spare tire just forward of the tail lights. Also the rear crossmember in front of the rear bumper is now shown correctly as being open on both ends, before it was shown as closed off.
    The attached sketchup drawing is done to scale and includes the front and rear frame for a 240Z. Can be viewed with the free program sketchup, download from Google (Mac or PC, can work with Linux). Can be zoomed in and viewed from any angle. The drawing was made from measurements from my own car and from the chassis dimension drawings to maximize accuracy.
    Can be converted to Autocad readable .DXF with Sketchup pro for importing into Autocad. May need an older version of Sketchup pro to make the resulting .DXF work with an earlier version of Autocad.
    I found it interesting that the inside frame rail to frame rail measurement on the rear frame rails where the spare tire well is on my car measured about 10 MM further apart than on the chassis dimension drawing. The manufacturer must have made a slight change there unless whoever made the chassis drawings was off a bit in that area. I made my sketchup drawing agree with the dimension on my car.
    Drawing does not show narrowed section on both front rails located about 5 inches behind the radiator support. I could not accurately define that narrowing with the tools I have so I left that off for now.
    Litecoin QR code for donation:

  12. Mikes Z car
    Hi all,
    I made a new engine bay light lens out of an empty nutrition drink tube that looks like a large translucent white test tube with a tube DIA of 33.8 MM, though it does not have to be exactly that to work. The nutrition drink is called Energize and has the words "Hardcore Energize bullet" on it with the word "Energize" much larger than the other words (Thank you to SteveJ for identifying the brand of drink for me since I had thrown away the wrapper). It is sold by Wall Mart here and I have read Walgreens sells it though not in the Walgreens we have (Several Energize offerings are on eBay now 23 Feb 2013). There is a colored shrink wrap covering on the Energize tube but the tube itself is translucent white. Another brand of tube that might work is the Profect brand tube though its color appears more neutral if the color at the top just under the lid isn't from shrink wrap:
    Energize Hardcore Bullet:_____Profect Protein Beverage:

    ******EASY WAY****** (see further down for how I did this the hard way)
    1. Cut off the rounded end of the nutrition tube so it is the same length as the original lens (33MM or 1 5/16" or 1.29") and scrape off any plastic burrs.
    2. Sand off open end on the side of a bench grinder disk or on a sidewalk to remove irregularities if any.
    3. Push into the light housing. You are done.
    Pushing the new tube into the housing will take some hand force if you use the same size drink tube I did and will likewise take some force to pull it back out to replace the bulb however the engine bay light bulb will typically last for decades as it isn't often used. This easy approach will result in the best looking light lens as you won't see any cut/grind marks needed to make the new lens twist into place like the old one did if you try the same thing I did (see "hard way" below). Note that I also made two new rubber gaskets out of a truck tire inner tube to be a weather seal between the lens and metal housing as the existing rubber seals in the metal housings I have had deteriorated.
    OLD lens/NEW Lens:....................Rubber gaskets:

    The three pictures immediately below are also on this related thread:
    http://www.classiczcars.com/forums/open-zcar-discussion/48344-240z-inspection-light-source.html
    White translucent tube for new lens material:

    DIA of new lens material 33.78 MM:..DIA of original lens 32.52 MM:
    ..........
    ******HARD WAY****** (see above for easy way to do this)
    The goal of doing this the hard way was to duplicate not only the look of the original but the way it twists on.
    1. Be sure any old rubber gasket or freshly made one is in place before doing this. I pushed the new lens into the bay light metal housing after cutting it off from the nutrition tube and put masking tape on it right up to the metal housing.
    2. I drew a line across the top of the four tabs and extended this line the width of each tab in a counterclockwise direction from each tab as viewed from the rounded end. Each tab will slide in its own slot as the lens is twisted on. I also put a dot where each side of the four tabs were to be used in the next step.
    3. I pulled out the lens and drew a straight line from each dot to the open end of the lens as a guide for grinding with the dremel small cylinder grinding tool.
    4. I ground the area down between the three lines for each tab so the tabs will slide over that area easily.

    5. Using a dremel thin cutting disk, I cut the slotted line I marked earlier. NOTE: Don't do like I did, take time to cut a little at a time and then test to make sure you didn't cut the slots too deep. You want a firm effort to twist the lens into place so it doesn't come off. If the slots are too deep the lens will be loose and can be cocked over at an angle which doesn't look good.
    Dremel tools I used:

    Note:
    As the drink tube is much longer than needed it is possible to practice several times to get the plastic cut/ground off right. I cut off each practice session to give new plastic to practice with before cutting the tube to final length. Plastic slivers from the tube can be melted on with a soldering gun while positioned next to the slot towards the open end of the tube if needed to get rid of any looseness if the slots get cut too deep.
  13. Mikes Z car

    Clock face scanned in for 240Z series 1

    · %s · %s

    BE SURE TO SAVE THE FOLLOWING ZIP FILE PICTURE FOR PRINTING NOT THE ONE VISIBLE ON THE SCREEN (keeps DPI correct to print to original size):
    clock face 240Z series 1 scan cleaned.jpg.zip
    For viewing but not for printing:

    The attached .ZIP file clock face is a scan of a 240Z series 1 clock. The original clock face was removed from the clock and placed on a scanner so there should be no perspective distortion. It could be printed out for a creative project if someone were so inclined and placed on a desk top clock face (might need white hands?) to make the clock look like a 240Z series 1 clock. To do this you could pull the hands off or possibly point all the hands in the same direction and feed the printed face over the desk top clock hands through a hole cut in the middle if one of the hands doesn't stick out in both directions from the post for the hands. Another option is to use a razor blade to cut a slit from the middle to one edge and make a small hole in the middle for the post the desk top clock hands are on. Usually it will look better if printed on photo paper.
    To print this the same size as the original clock face select 100% scale in print preview and don't change the resolution from the 600 DPI the .ZIP file image is currently set to. Note that the scan here includes the four curved slots that allowed light through from inside the clock for the night time light for the clock, these curved slots would not normally be seen when the clock is installed in the vehicle and may be cut off.
    To change the printout size change the DPI or resolution as it is also called in your print preview. To make the printed face half as big as the original clock face change the DPI to 1200, to double the size change it to 300 DPI.
  14. Mikes Z car

    Access door for fuel vapor hose

    · %s · %s

    Hi all,
    I put in an access door for the large fuel vapor hose that connects on top of the back of the gas tank making it easier to change out the hose. After dropping the tank to change that leaking hose I realized I wanted easier access to that hose though I recognize it might be a while before it needs replacing again. I figure anything that makes upkeep easier prolongs the life of the car.
    I put an aluminum rod approx 1/4" DIA about 10 inches long into the part of the hose that connects to the gas tank that was to be bent into a "U" shape to keep the hose from kinking and closing off. I verified this after bending by blowing through the hose. The hose I used was not OEM. It is no doubt stouter than needed as it is rated for 350 PSI, marine use and is ethanol resistant. It fit fine on the tank though on the other end I had to slit one side with a hacksaw to get it to fit over the nylon hose connector at the fill tube. I clamped it on with a radiator clamp and sealed the slit with Seal All. The hose was stiff to install but should last a long time.
    Mike
    Final result, painted access door (other pictures taken before paint):

    View thru door (new hose):......................................................Door closed:

    Bottom view no tank:...............Access door seal:

    Access door hole location:........Original hose seen here:

    Fuel vapor hose I used (very stiff hose) (pictures of numbers seen on hose):
    Weatherhead 5/8" H10110 Made in USA 1008, MSHA 1C - 46/6:

    End view with ruler showing diameter:

    New hydraulic hose is a tad too big to allow grommet to fit in hole in car so I just pulled rubber grommet down the hose slightly and didn't use it. Hose is very strong (rated 350PSI), IMO doesn't need grommet:
    Seal All applied next to filler hose:

  15. Mikes Z car
    Many thanks to Jeff G 78 and postings by others for help with this. I noticed the instructions on the standard tank seal can called for thoroughly stirring the tank seal which I thought I had done but when I poured the seal in the tank there were a few lumps. If you look closely at the flat surface on the right (tank baffle) in the completed picture below you can see a couple of small lumps likely from lack of stirring. I used a pint and a half which is a half pint more than what POR says you need so it should be fine.
    I spilled some tank sealer on the outside of the tank and thereby discovered how durable the POR standard tank sealer is when I started wire wheeling the exterior of the tank in preparation for painting.
    Mike
    Original dirty tank:

    After acid cleaning with hydrochloric acid (per the bottle, this is a substitute for muriatic acid commonly used for this):

    After marine clean and metal ready:

    Completed (pink color from camera light):

    More details of my experience:
    Gas tank seal process.txt
  16. Mikes Z car

    Hatch anti corrosion interior passageways

    · %s · %s

    Hi all,
    I went to spray the interior metal passageways of my 240Z hatch with a Transtar Amber anti corrosion spray can and noticed there is a reinforcement plate on both sides and top of the hatch. To spray the two passageways created by this plate on the sides was easy as I just had to guide with my hand the 3 foot long spray wand above and then below the reinforcement plate as you can feel the end of the plate with your hand. See drawings. After I did this on both sides I drilled a couple of holes at the top middle of the hatch to give access to the top and bottom of the reinforcement plate in that area. Access to that area can also be had without removing the hatch as I did by drilling in the corner, see last drawing. Be sure the two corner holes line up with the two passageways at the top of the hatch especially if you use the Transtar spray wand as it isn't flexible enough to go around tight turns. I plugged the holes later with plugs I got at an auto parts store and sealed them with silicone. The animated .GIF drawing shows the location of the reinforcement plate. The end of it can be seen by looking up in the bottom inside area of the hatch with the interior finisher removed.
    Mike
    Where I ran the spray wand on sides of hatch:

    Black U shaped area is reinforcement plate (click for animation):

    Drill two holes for spraying top of hatch:

    Transtar Amber Spray can (spray can on left):

    Wand used was 3 ft long, sprays 360 degree pattern: (I found mine in a local automotive paint shop, can also perhaps find with google)
    #4471 Transtar Rustproofing Wand (includes three 3 ft wands and shorter red wands):

  17. Mikes Z car

    Map light stuck fix

    · %s · %s

    Hi all,
    The map light in my 240Z got stuck so that when the switch was pushed in to make it turn on or off it would push in and wouldn't pop back out. This was largely due to the top and bottom of the assembly pushing in on the clear plastic switch cover causing the clear plastic to drag. To cure this I glued in a sawed off ordinary lead pencil to bow out the top and bottom of the assembly reducing the friction on the clear plastic switch. The pencil length that worked well for me was approximately 26/32 of an inch and was epoxied in place when it was working right. I painted the yellow pencil gray to hide it behind the clear plastic better. A small bolt with a series of nuts would likely also work and would be adjustable but use lockwashers if you do this.
    Final result:
    Light off

    Light on

    I also put a small amount of light machine oil on the switch itself on the white plastic post that sticks out of it and used a pocket knife to scrape smooth the plastic adjacent to the moving end of the clear plastic switch to make it more slippery. The plastic seemed to have dirt on it that was causing friction.
    Note that the clear plastic switch cover on my car would come out of the white housing on either end once the heater fascia cover was unscrewed for access to the map light.
    Mike
    Modification notes:

    Bottom View of post location:

    After modification before installing in car:

  18. Mikes Z car
    This will describe the lock latch modification only and will not address the door warping issue further.
    I noticed the glove box door on my 240Z would not always stay latched. The first thing I tried was to slide the lock mechanism fore and aft after loosening the two screws that hold it on as they are in long slots. I had previously modified the latch on the door to stay in position better using a cotter pin (see part 1 of 2 blog post on this) but the half with the locking mechanism needed work so that the latch would hit at the right angle. I did this in two steps. To do the first bending operation I pushed in the lock with the key so the vise grips wouldn't hit where the key goes in and used an aluminum rod 3/16" in diameter as a fulcrum.
    Step 1: (click for animation)

    Step 2: (click for animation)
    The second bending operation used vise grips on both sides of the very end of the tang to slightly turn the tang so the latch would hit at a better angle:

    The door closes every time now with a firm click and
    stays closed. Be sure to click on the last two pictures below to see the short movies showing the latch before/after action.
    Jan 2012
    Latch tang result from step 1 and step 2:

    Closing action before: ________Closing action after modification (click either for animation):

  19. Mikes Z car

    Horn Button DATSUN label printed

    · %s · %s

    I had a horn button but no badge on it with the word "DATSUN" so
    I selected a font similar to a real badge and resized it to print at the right diameter to tape to the horn button. See below the asterisks for another print option using a scan of a real badge that I obtained after I originally wrote this. Continuing here, the font selection came out okay, see attached picture of result and the file I printed the word "DATSUN" with. Printing the label on photo paper if your printer supports that or having it printed at a kinkos type of print business might significantly improve print quality and make the background print blacker. I covered the printout badge with clear packing tape and cut out two round circles from a document protector plastic to put on both sides of the printout to keep the printout badge looking okay. I used a bench grinder and a flat abrasive tool to grind down the edges to a fairly round shape. I taped three little pieces of clear packing tape from the front outside edge around to the back to hold the assembly together. Then I rolled four pieces of clear packing tape around on itself with the sticky side out to tape the whole thing to the horn button. I may get a real badge someday but this printout will work until then.
    To make the size correct in print preview select 100% as the size or 72 DPI which mean the same thing in this case. If the print is the wrong size adjust the DPI to be different than 72 DPI, maybe try 80 or 65 or some other variation. Printing at 80 DPI will make the print a bit smaller, 65 will make it larger.
    Mike


    ***************************************************************
    Note that since I originally wrote this I obtained a horn button with the metal label Datsun on it. After I removed the metal label I scanned it in and it can be seen below. I touched up the scan to get rid of dust particles etc that were visible. It was scanned in at 400 DPI, using that resolution when printing should yield the correct size.

    Back of horn button and badge label dimension information:

    The mounting post is in a recessed rectangular area so that the length of the post
    and the thickness add up to more than the overall distance from the
    end of the post to the other side of the label if that makes any sense.
    Symbols on back of badge label:

  20. Mikes Z car
    Glove box latch fix and door warp prevention (see part 2 of 2 of this blog post for bending the latch tang on the upper half of the door latch on the body of the car to make the latch click solidly every time)
    I wanted to make the glove box latch work right and to stop the door warp by weakening the overly strong light switch spring. Note that ZULAYTR posted in a thread:
    http://www.classiczcars.com/forums/interior-s30/19881-glove-box-door-light-switch.html
    as to how to straighten out your door if it is already warped by heating it up and bending it the other way.
    To stop the latch on the door from sliding if it is loose:
    1. The door latch on my car was loose (a two piece assembly) and sliding even when tightened so I took it out and flattened with a hammer the back 3/8 inch part of one end of the U shaped piece closest to the hinge.
    2. I drilled a tiny hole thru the U shaped piece and the lip on the flat piece it fits in and put a cotter pin through the hole to keep it from sliding back and forth. There is room for a tiny cotter pin. On my car this hole needed to position the parts so that the U shaped part is slid all the way into the flat part it mounts on to mate to the upper latch right:

    As information the upper half of the glove box latch on my early 240 is held in place by two 4 MM metric bolts with a .7 pitch.
    Preventing door warp by weakening the door light spring:
    1. To avoid further warping of the glove box door I replaced the spring in the glove box switch with a weaker spring; what Ace Hardware here calls a no. 3 spring.

    Spring specification:

    2. The switch assembly, called "nut spring" in the fiche can be pried out with a pocket knife.
    3. Bend the legs of the chrome colored retainer out just enough to allow it to pop off of the rest of the assembly. The spring will pop out at this point. The "legs" of this item fatigue easily and will break if bent too much so limit bending as much as possible.
    4. I cut off part of the no. 3 spring to make it even weaker however if you do this be sure the spring is still long enough to push the copper connection on the end of the plastic plunger rod into firm contact with the chrome colored retainer as that is where it gets its ground connection. I tried shortening the original spring but the spring still felt too strong. After replacing the chrome colored retainer on the rest of the assembly pull gently to test that the two parts are gripping each other. If not it is possible to gently squeeze the retainer with pliers just under the lip to force the legs to grip tighter. If the legs need to grip the sides of the hole better try putting a straightened out paper clip under a few of the legs in the middle and use pliers to squeeze the end of the leg to force it to bow out so it will grip the hole it fits in better.

  21. Mikes Z car

    3 July 2009 copy of 240z registry

    · %s · %s

    Attached is a copy of the 240Z, 260Z, 280Z and 280ZX registry from 3 July 2009. If this is a copyright thing or another kind of violation I will delete it just let me know.
    Mike
    Z Car Registry.xls
  22. Mikes Z car

    Five floor board holes repaired

    · %s · %s

    This weekend I had the 5 floorboard sheetmetal pieces welded in to repair rust holes. Also the driver's side floor pan frame rail was straightened as it had been used by a floor jack. Unremoved rust makes the mig welder spit sparks. First I drew on the floor with a marks a lot around the holes using straight lines to make the cutting and fitting of the new pieces easier. After I cut along the straight lines using an angle grinder I made cardboard templates from the floor holes. I bought a piece of sheet steel 16 gauge from Thrifty hardware and put the templates on that and drew on the metal to outline the new replacement pieces. I used an angle grinder to cut them out but I had to use a bench grinder to adjust the shape of the 5 repair pieces to fit properly. Some would have overlapped the metal which would have been easier but I didn't want an area to trap moisture. 16 gauge is slightly thicker than the 17 gauge originally on the car.
    Coincidentally the gentleman who did the welding used to own a scarab 71 240Z. He put nitrous on his and I don't know if that is typical for scarabs but he said he had trouble with the rear shocks coming up through the floor and he had to weld reinforcement in to prevent that.
  23. Mikes Z car
    Hi all,
    I soldered both ends of all rivets and all wire crimps to fix fuse box overheating. Rivet and crimp location shown here:

    Other screenshots from drawing:

    Drawing:
    240Z_fusebox_early_1970_final.skp.zip
    I pulled the fuse holders from the fuze box before soldering to prevent melting. Sanding or cleaning the fuse holders with copper cleaner and bending the fuse holder together to tighten the grip on the fuse also can help with overheating.
    You will need sketchup or sketchup viewer to look at the attached drawing which can be downloaded for free from Google. The drawing is 3D and can be zoomed in for details. It shows the inside/outside of the fusebox including the fuseholders, the colors of the wires and has text to indicate the destination for each wire. It also shows the cables that go out the back and the connectors on the end of the cable with all connections labeled. It is very close to being a scale drawing.
  24. Mikes Z car

    Gas Tank sending unit modification

    · %s · %s

    This mod has been in my car for 5 years, works great.
    Before/After modification (click for animation):

    I noticed low gas gauge readings. When I looked at the sending unit in my 240Z gas tank I saw that it has a worn curved track across the coil of resistance wire where the copper float arm connector slides across the coil. The sending unit I have must be original gauging from the large amount of wear on the wire. Since the rest of the unit looked good I figured I could significantly increase the life of the sending unit by shortening the copper arm just enough so that the arm contact point slides over the wire on a different part of the wire where the wire is not worn at all. The steps I used for this were:
    1. With the unit out of the tank and disconnected from the car, I measured the resistance at the two connectors that go to the car at max/min travel of the float arm. Mine was close to 8 and 90 ohms. I used this info when completed to verify proper operation.
    2. I remove the protective flat cover over the coil that is held in place by three tabs. I straightened the one tab that is twisted after it goes through a small slot. Once it releases the other two will slide out.
    3. I marked a small dot on the coil using a marks a lot or similar in line with the very end of the copper arm as it swung in both extremes of direction.
    4. I loosened the set screw allowing the copper arm to swing over a wider range of motion than before.
    5. I shortened the effective length of the copper arm by bending it up and then down so that it is shorter. It wound up looking like this:
    ________/\________
    It was sticking up in the air at this point, this is how I fixed that.
    6. I adjusted the pressure on the arm so it contacts the coil at a gentle but slightly firm pressure. The pressure can be adjusted by swinging the arm over the end of the assembly and pushing down to over extend it. I noted that the arm approached the coil at the same angle as before and that the new position of the contact point is now on new wire that had not been worn.
    7. Using fine sandpaper I sanded the wire where the contactor will be contacting the wire to assure a good connection. Sanding with the wire is probably better as sanding across it like the arm swings might work the wires loose.
    8. Proper pressure can be verified by using an ohmmeter on the two connector posts as the arm is slid by hand over the coil. I wanted to see a fairly smooth transition from about 8 to 90 ohms, readings outside of that can be fixed by what i did in step 9.
    9. I swung the copper arm and the float so both are at the end of travel they would see at the full tank position. Full tank position for the float will have it at its extreme end of travel in the direction towards the end of the resistance wire that has a wire going to the car connector. Holding the float in that position I moved the copper arm that contacts the resistance wire so that it lined up with the dot at the end of the resitance wire nearest the float that I marked earlier. I retightened the setscrew firmly. I verified proper setscrew setting with an ohmmeter to verify I saw close to the same readings at max/min float positions I saw in step 1.
    Note that there are a couple of other mods to fix the sending unit, the links to those other two ideas are here:
    1. I added a wire to improve grounding of copper arm. See:
    http://www.classiczcars.com/forums/showthread.php?t=35258&p=318623&viewfull=1#post318623
    This is how I added the wire (loop the wire a bit to reduce mechanical stress on soldered connections so the wire doesn't break off):

    2. Use crazy glue to hold down wires and prevent them from moving when the sliding contact rubs on them:
    Http://www.classiczcars.com/forums/showthread.php?t=35258&p=318628&viewfull=1#post318628
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