cgsheen1

Firstly, the fact that it's an L28 or has SU's has no bearing on this distributor swap. None of the Tach rewiring was actually necessary. You really just needed to install the distributor and provide it's wiring. The 240Z Tach is "sensing" the current drawn by the coil. It would make sense to use a stock coil or equivalent. The 280ZX "matchbox" doesn't care about the coil. (It's operation isn't affected by the coil). It also may make sense to leave the stock ignition wiring in place as well - as the Tach thinks it is... Secondly: You can indeed test the ignition wiring. Remove both B/W wires and the G/W wire from each other and the coil. Isolate them. Turn the ignition switch to ON. Test those three wires with a multimeter. ONE of the B/W wires should show BATTERY VOLTAGE. The other two should show ZERO voltage. (Originally the B/W with voltage at IGN ON would be connected to one side of the ballast resistor, the G/W to the other side of the ballast resistor. (which THEN goes through the Tach) The B/W showing no voltage (at the time of test) should connect to the "+" on the coil (this actually comes FROM the Tach). (The "start signal" (+12v) originally would bypass the ballast to deliver un-resisted battery voltage to the coil for starting)) It's your call whether you put the ballast back and wire it up stock OR just connect the B/W that gets power at IGN ON to the G/W wire and put the other B/W on the coil... I prefer making things as simple as possible by NOT introducing EXTRA troubleshooting steps SO I would make things stock and troubleshoot from there.

Yes. Get the engine to true TDC and mark it both pully and distributor. Please don't leave the oil pump attached. You'll have to realign the distributor spindle with the crank gear regardless. This is a lot of work to repair a small leak that's not under pressure so I recommend that you get another head gasket. You'll only use the front bit as a new gasket for the front cover - and discard the rear - so you don't need to go crazy with the type, cost, availability. Remove the front cover and clean all the mating surfaces scrupulously. Cut the head gasket at the block / head junction with a very sharp instrument - careful with the underside of the aluminum head. You want it cut very cleanly & tight against the block. Use that piece as a pattern when cutting the front off the new head gasket but make it just a hair longer on both sides to be sure. And make sure the cut is SQUARE. Clean the face of the block and underside of the head scrupulously. Use Acetone or lacquer thinner on lint free cloth or towel to remove oil and residue on ALL the mating surfaces. Especially underside of head and block where they meet. Check your new mini head gasket for fit and adjust if necessary. Prepare your gaskets (new head mini gasket, right and left front cover gaskets) by THINLY coating them with fuel and oil resistant gasket maker. I recommend the "pinch method" - latex gloves, put a dab of gasket maker on index finger, pinch with thumb and rub a bit, pinch the gasket between your fingers to cover both sides with a thin coating as even as you can get. Then add bit more to that corner between the head and block - make sure the new head gasket seam is sealed when you place your new gasket piece in place. (That's most likely where your current leak is coming from.) The top corners of the cover need your attention. When you put the front cover in place don't tighten all the front bolts first while you're doing it. You want a good seal between the head and front cover and the only clamp is from those two small bolts on top. Snug the front cover in place by alternating pressure on the block face and head underside to pull the cover into that corner made by the block and head. Snug each direction a bit while the cover can still move slightly so you're sure you get a good clamp to the head. Then you can put everything else together. I've noticed that most L engine oil pans have been mis-torqued and the metal is deformed around many or all bolt holes. I pound them back down level with the mating surface and use the same pinch method to apply gasket maker. (Ya, I've tried doing them dry but,,,) (I've done this by trying to leave the head gasket front in place and also have been on the receiving end of someone else leaving the head gasket front in place and trying to re-seal it after pulling the front cover... After all that work, I prefer a method that's more likely to maintain a good seal. That's why I now replace with a clean, dry section of gasket. I use the pinch method for gasket maker on gaskets because I've seen way too much silicone squeezed off gaskets and into places it should never be. Lastly, these engines weren't built for modern oils (synthetics) which don't have the necessary polymers to plug up the minute gaps. So they need all the help they can get...)

The hatch glass is a bit tricky because the end opposite of your pull wants to push out of the hole. We've always done it with the hatch mounted and you really need some help keeping the glass from moving too far opposite of the pull. I used to use very thin diameter cord but found it more likely to tear the rubber if you weren't careful and/or well lubed. I switched to soft "clothes line" (cotton or poly) cord and have been doing it that way for years. It's probably 3/16" or 1/4" and I soak it before use. Easy pull and no tearing. We've done more than a dozen this way. I think my son did one solo one time but I never have... Granny is correct on the constant pressure, pulling the inside rubber outward as you go. We pull a bit of cord, press the glass down while pulling the inside rubber outward to help set the glass as we go. The farther along you get the more the glass will be able to settle so the guy on top needs to keep going back with pressure while not allowing the glass to move out of the hole. We normally start on the top but I don't think that really matters. We also don't lay inside - you can reach the string pull from outside and it's then easier for the pull guy to pinch the interior rubber to the outside helping to set the glass and weatherstrip into final position as you go. Keeping the glass down in the hole is paramount. Slow and smooth is fast in setting windshield and hatch glass.

This doesn't make sense to me as pull should be fairly equal on each side. The "Y" configuration of the cable should be self-adjusting (a saddle that the cable can slide in). None-the-less sounds like you need a shorter length somewhere to get them engaged fully. The actuating lever on the caliper looks pretty stout. Maybe some pictures?

There is adjustment to the parking brake system. You probably won't like where it's at...

Max vacuum will be at deceleration - idle second highest. Under load vacuum will diminish and cruise vacuum will be kinda middle of the MAP range (Manifold Absolute Pressure). Except at Idle, MAP is always changing and LOWERS when you have your foot in it. I think your assumption that advance might hit 55 degrees is likely unfounded. When the mechanical advance is highest, vacuum advance is nominal. When vacuum advance is highest, mechanical advance is non-existent (except on deceleration perhaps where advance is not likely to be a problem). I'm going by what I see on my MAP gauge - correct me if I'm wrong. BTW - my MAP gauge goes BOTH ways... Oh, and I don't think Zed Head wasn't talking about vacuum ports on the balance tube - he was talking about the port on the carb near the throttle body...

And probably coilovers with camber plates...

The three that I have are all the early design part (guess that makes sense). Like the pic kats posted - no holes. I don't have the later part to make a comparison with so I can't comment on if the late 260/280 part could be made to fit the earlier Z's. (But since the "splash-board engine" fastens to the lower core support which changed shape starting with the late 260 AND the radiator also changed size and shape, you'd have to assume the "splash-board engine" requiring a different shape as well. Knowing Nissan, I would also assume that most of the mounting points would remain the same on the frame and cross member.)

My son ('76 280Z (which was factory Gold Metallic BTW)) used those years ago to adjust the rear control arm as much as they would allow. He lowered his 280Z mightily and even at maximum they didn't bring the toe back all the way (especially on the right side which has always been weird to me). Depending on how much of a change you've made, you may not need to worry about the precision. Just saying... (and since he stuck with stock struts, he never got his camber even close...)

I don't think that's true. You know that the early 260Z (like mine) has a 240Z radiator core support. The late 260 and the 280 changed the lower support downward in a sort of deeper "U" fashion. Since the "belly pan" attaches to both the frame rails and the bottom of the core support, there has to be a difference in design for the pan. A quick look at the parts list on carpartsmanual.com shows "splash-board engine" with one part number (74810-E4100) TO 08/74 and a different part number (74810-E4200) FROM 09/74. The same part number for the early 260Z shows up for all 240Z's which I would expect. I'll look at the three that I have and see which part they are. If I have one of each, I'll post a pic with the physical difference.

I haven't seen a Precision set since Covid but everything we either bought or customer supplied before then was barely adequate for the door weatherstrip. (and we did quite a few) We got to compare them to original factory weatherstrip when Bob brought in the 1975 "Museum" 280Z and there is no comparison - other than black and they fit the hole... Okay I'll admit that the Precision I put on my own Z was 12 or 13 years ago and it was adequate but I much preferred the used KIA weatherstrip. I pulled out the KIA and replaced it with Side-bulb Welt before Covid and consider it to be the best of the three. I'm going to use Top-bulb Welt on my hatch as soon as Arizona Winter (AKA Summer) is over. HOWEVER - NONE of it compares to the factory weatherstrip for the doors. But, if someone could faithfully reproduce the factory door rubber it would likely cost way too much to buy...

If DIY - 3/8" plastic tubing works best (will last longest and easiest to replace if you need) - think plumbing supplies. Doesn't matter if it's poly or PEX but you're looking for slightly flexible - NOT vinyl or rubber. something like this (maybe home depot, lowes, or ace hardware): https://www.amazon.com/s?k=3%2F8+od+tubing+water+line&crid=4Z2MEURM8G1N&sprefix=3%2F8+tubing+water%2Caps%2C174&ref=nb_sb_ss_ab-sx-reranking-v3-desktop_3_16 https://www.homedepot.com/s/3%2F8" poly tube?NCNI-5 https://www.homedepot.com/p/3-8-in-O-D-x-20-in-PEX-Toilet-Riser-with-Plastic-Compression-Sleeve-P1-20DL-F/100552807 (yup, plastic supply tube for toilet (closet (as in water closet)) or lavatory (as in bathroom sink) or kitchen sink (as in kitchen sink...))

Overdrive gear (final gear ratio) varied somewhat in the various years of the 5-speed... Difference shouldn't be huge, but...

I have a close ratio ZX 5-speed and 3.54 R200 and get the same as Dave - ~80mph at 3K. But I don't have anywhere near the humidity!

I also don't see the dovetail body piece (10- ASSY-DOWN STOPPER DO(OR) 80581-E4100) below the door striker. Not necessarily a must but definitely a help as it also can provide a little push to open the door and also help with the alignment of the door to the body. As noted above, it's the alignment of the striker in relation to the door latch that is the problem. The rotating latch should never end up jammed against the striker or it won't be able to turn (rotate) and release. The striker on the body needs to be aligned so the round latch doesn't touch it's sides - only the lobe(s) coming out of the latch. The oblong lobe should contact the striker first and begin the rotation of the latch that's necessary for the door to close and reopen properly. When aligned properly, the round lobe rotates and comes to rest in that bottom groove on the striker when the door is closed. The lobe is the only part of the latch that should be contacting the striker. (There are two lobes - one with a rounded end - the other is oblong. The oblong lobe contacts the striker first (and from the factory has a hard-ish rubber covering which is generally non-existent in most Z's after 40+ years of use)) If you had x-ray vision, you could see all this first hand... To recreate the factory oblong lobe covering, I use a piece of 3/8" plastic tubing first cut to length the width of the oblong lobe, then slit down the length of the tubing and pulled apart to create a "C" which can be slipped over the oblong lobe. This adds the width the factory intended and helps the door to close and latch smoothly. Research "Slamming Door Issue" for info.

Almost everyone says you need a ZX 15/16" master or a Wilwood BUT I use the stock 7/8" and have since I did the vented rotor / S12W swap several years ago. My youngest son did the same swap at the same time but used the ZX master. I can tell a slight difference between the two. This was after a NASA weekend on stock brakes... I first tried the 4-piston swap on my stock rotors. MINOR upgrade which I was disappointed with. That led to the vented rotor swap which led to Porterfield friction front and rear. I do quite a bit of mountain driving. The turbo Z is uphill monster and these brakes don't fade on the downhill partly because of the rotors, mostly because of the improved pads and shoes. If you use 300ZX vented rotors, a spacer for the rotor is unavoidable as are the vented rotor calipers. The simplest route would be new stock rotors and Toyota 4-Pistons for solid rotors with some decent pads...

I installed one in a series one a couple of years ago for a local guy. I have no idea about the sound quality but install was very straightforward, faceplate fit well, and it looks very nice. I don't recall having to do anything out of the ordinary and the fit adjustment was very easy. I moved his antenna switch (as he had a stock type electric antenna) to the console so it didn't impact the faceplate and also didn't modify any stock features (meaning it could be removed at any time and reverted back to factory config and leave no trace of the modification...)

What granny said and pull the drums and look for scoring, scratch, rubbing - not so much on the area where the shoe (friction) meets, everywhere else. Put up a pic of your shoes and springs and cylinder.

Okay, you did the bushings, springs, and struts plus some powder coat - but what did you do to the rear braking system? Shoes, springs, retainers, cylinders? You left the rear axles and bearings intact?

Rota Grid 16x8 +10. I run 225/50 ZR16 (my fenders are rolled (as in: the inner flange with no pull, and as much as you can roll the rear inner flange as it gets pretty "thick" near the exterior...) I have coilovers and camber plates but I run the rears nearly flat)

Randy, you can get side bulb welt just about anywhere including amazon. The Kia weatherstrip is nice and you can hide the seam you have to make under the kickplate, but the 90 elbow isn't sharp. With new side bulb welt you can 45 degree each end at the upper aft corner and get the bulb in the dimension you want to completely fill all the gaps between the door and body. (personally, I discovered the Sportage weatherstrip when I was looking for a Honda blower motor for my Z. That's when I found the Kia blower and used it to retrofit my defunct stock blower rather than using the Civic blower. I can't remember the exact year - been too long - but I'm pretty sure it was an early 90's model of Sportage)

When you pulled the connector off the ECU did you check the contacts on both the plug and the ECU? We've seen water damage (corrosion, oxidation) on the ECU connector from cracked and/or leaking windshield gaskets.

Or remove the relays, get back to stock, troubleshoot the circuit and get the headlights working, then get the relays back in... May have helped to know about modifications from the start.

The headlight circuit is fairly straightforward. Disconnect both headlights from the harness just in front of the radiator core support (easier than pulling the plug from the back of the headlight bulbs). With the headlight switch in the ON position: Right side: You should read battery voltage on the RED (R)wire. Left side: Battery voltage on the RED/YELLOW (RW). Continuity check: You should have GROUND continuity on either the RED/WHITE (RW) OR RED/BLACK (RB) depending on the position of the dimmer switch. This will be the same on both headlights. The ground continuity should switch wires when you pull the dimmer switch. At least one of these things will probably NOT be true because your bulbs don't light - but you need to know which. https://www.nicoclub.com/datsun-service-manuals has the 1971 240Z Supplement which has the electrical diagrams at the end. From the electrical diagram you'll see that the dimmer switch operates on the GROUND SIDE. The switch gets it's ground from the Lights/Wiper Combo Switch. Power comes from the battery through the Combo Switch -> fuse box (one fuse for each headlight) -> bulb (with several connectors in between all that).

That's a shame. A Z that deserved (deserves) to be restored - but who has the $$$$$$ to see it put back near to original... It would take the work those guys in Japan did in restoring the 1969 Fairlady Z.