Chickenman

As per FSM, #1 hole is factory position for new chain and components and unshaven head. If you actually got the cam sprocket on the Cam.. the chain's not too tight. New chain with new guides and tensioner can be an SOB to install. Double check the notch and groove for Cam timing as mentioned. As long as they're in spec, you should be Golden. Head or block shave may require using #2 hole to align notches. I usually prefer to have the Timing Cover removed and the oil pan loose when I setup a new chain, tensioner and guides. Two head bolts loosely installed in the back of the head. I position everything but leave the top bolt loose on the curved guide. Then I swing the curved guide in to position and adjust it to provide the specified amount of clearance on chain tensioner. Then install the TC over the dowels. Secure TC with fasteners. Check that bottom of TC is flush with block. Assemble and torque head bolts, then bolt up the oil pan last. Honsowetz recommends that method... seems to work well. Edit: I just checked my 1976 280Z FSM and tensioner protrusion, with all new parts, is supposed to be set at 0.0mm by adjusting the curved guide. However, I do like to have a bit of clearance there just to make sure things aren't too tight. It also makes putting the Timing Cover on easier as you can move the head up a bit and fit the TC over the dowels at front of block. .050" to .100" should be sufficient clearance with all new parts

1: First of all, make sure the bolts you are using are not too long and bottoming out. 2: Top thermostat housing could be warped. Check with a straight edge. Take it off and get some sheets of wet and dry emery paper in grits 100, 200 and 400. Get a flat steel plate or a flat sheet of glass. Use WD40 as a lubricant. Start off with the 100 grit and lap the stat housing. Lap housing in a figure 8 pattern. Any high spots should become readily apparent. Lap with 100 grit until housing is totally flat, then finish by polishing with 200 and 400 grit. You can also lap the bottom housing, although that one is less likely to warp. Use new gaskets every time. I prefer to use Permatex Aviation Form a Gasket ( Brush on liquid ) as a sealant. Much tackier than RTV, although a bit more difficult to remove. Will never leak though!! GL.

You have to be careful when you read catalogs. You don't select plugs based on what year of Dizzy is in your car. You select plug heat range based on compression, cylinder running temps, type of emissions controls and other engine variables. Engine modifications such as higher CR longer duration cams also have to be taken into consideration. Note: The 280ZX NA motors had really low compression ratios and specific emissions controls, which required a hotter spark plug than other years. Mainly because the cylinder temps were lower. Those particular engines ran a lot of EGR for emissions purposes. EGR reduces combustion temps and tends to foul plugs, especially when you run a large amount of it. My question is... Are you running a completely bone stock 1979 280ZX engine in your 1972 Z? I suspect not..... I'd stick with the NGK 6 range if the engine is running clean. If it's pig rich and burning oil. then yes, 5's might be needed. But I've never seen a healthy L series engine require anything hotter than a 6. NGK...except maybe way up North. NGK 5 plugs in a healthy Z motor definitely run the risk of pre-ignition under load or on the Freeway. With a Matchbox dizzy you should be also using a resistor plug. The non resistor plugs were only recommended for low output ignitions such as points and 1975/76 Trignition boxes which are weak sauce. A resistor plug actually causes a higher flash over point to be created, which aids in cleaning plugs. But you need a decent amount of amperage to support them. The ZX Match box dizzy has lots of power. Use a projected tip as well. That will place the spark tip slightly deeper into the combustion chamber and will produce a better flame kernel. In a clean running L series with 9.0 to 10.5 CR and a Matchbox dizzy I would run a BPR6ES or BPR6EY. Those come pre-gapped at .8mm ( .031" ) , projected tip, resistor. The S suffix is a standard tip. Y is a V-groove design. You could also run a BPR6ES-11 or BPR6EY-11. These are the 1.1mm ( .042" ) gapped version of the previous plugs. The Matchbox dizzy has more than enough grunt to fire the larger gap. A larger gap generally produces a bigger spark kernel ( a good thing ). Only problem is sometimes the longevity of Cap and Rotor is sacrificed with the larger gap plugs. Always use a good Spiral Core spark plug lead such as MSD or NGK. NGK spiral core leads are very high quality. Edit: NGK's plug site recommends a BPR6ES plug for a stock 1971 240z. That should tell you something right there.

If you cannot find a 160 F thermostat from Nissan, and you still want to run one, you can use a thermostat for a mid 70's Mopar slant 6. There a bajillion of these things made and 160F stats are fairly easy to find. Order a 160 stat for a 1975 Dart 225 slant 6. Rock Auto has them. I used Mopar 160F thermostats all the time im my racing Datsuns back in the 1970's. Despite my earlier reservations about Stant quality control, they are still a decent product. Not a good as 20 years ago when they were made in the USA, but a good second choice if an OEM Nissan 16 F stat can't be found. https://www.rockauto.com/en/catalog/dodge,1972,dart,3.7l+225cid+l6,1088434,cooling+system,thermostat,2200 Stant Premium 160 F #45356 = $4.02 USD Gates Premium 160F #33006S = $3.87 USD

So you currently have a Brand new Nissan 76.5 c ( 170F ) thermostat in the car. That should be good enough for 33C weather easily. I've run my Z in 38C temps in traffic with the AC on and with a 180F temp stat. Car never has cooling issues now, but that is ONLY after I had the 3 core Rad boiled out and everything in tip top shape. Is the rad stock? You may want to consider upgrading to a heavy duty aluminum core rad is your old rad is a stocker. MSA and other sell them at reasonable prices. Don't buy the cheapest one. Get something decent and not made in China. Not much point boiling out a stock Rad in your climate. My situation was different, as rad had a custom triple core already installed. It just needed cleaning.

Picture of an old radiator core before and after a good chemical " Boil out ":

Yes, happens all the time. My car originally came with a nice 3 core custom Copper rad. Should have been enough to cool it in Death Valley. Unfortunately the PO had never changed the coolant/antifreeze in over 10 years and all the anti-corrossion additives were shot. PO also lived in am area with " Hard " water so rad was clogged with calcium deposits. The problem didn't " reveal " itself until we got into summer temps of around 30c. And I also got the non-operational AC working two days before leaving on a California holiday. With the warmer temps and the AC working, the clogged radiator could no longer handle the heat load. It started over heating badly with the AC on. Boiling out the rad totally cured the problem. The core tunes came out all nice and sparkling clean and the Rad was able to cool like new. You can drain the water level down below the top level of the core tubes and then have a look at them with a good flashlight. Quite common to see these core tubes almost totally blocked with calcium, rust and other deposits. If the car was run with straight water or old antifreeze ( 5 years or older ) then corrosion happens rapidly. Find a good rad shop in your area and have it pressure checked and " Boiled " out. Make sure they do a thorough job. Take before and after pictures inside drained rad.

Oh I know what you mean about OP's ongoing pension for indecision. Which is one reason why I seldom respond to his threads any more. He is sloooowly getting there though. I believe I recommended a Factory Nissan 160 thermostat over a year ago.... maybe two years. Maybe that is where he's coming from. If he can find a factory 160 stat, I still stand by that recommendation. All part of solving his fuel peculation problem, which he is finally, finally slowly solving But yeah, it's really disappointing the state that the aftermarket is in these days. Global out sourcing has only helped the Bean counters. Quality control has gone for a huge nose dive. So for some things I'll only buy genuine factory parts. GM, Bosch and the Japanese groups seem to still have quality control over their OEM line ups. Everything else is suspect to me now.....

Nissan part number for Tropical stat is 21200-78502. Supercedes to 21200-F3160. Nissan Parts Deals is showing limited availability. I'd call them and check stock and confirm temp stamping. https://www.nissanpartsdeal.com/parts/nissan-thermostat~21200-78502.html Available on E-bay as well: Confirm temp rating is approx 71.5 C= 160 F by question to Seller. Don't worry about application http://www.ebay.com/itm/1979-1986-Nissan-200SX-280ZX-Pulsar-NX-Sentra-Engine-Coolant-Thermostat-OEM-/191579574572?fits=Make%3ANissan&hash=item2c9b08512c:g:ueoAAOSwBahVaOEk&vxp=mtr

BTW, I compared a Stant Premium replacement thermostat for my 280Z to the original Nissan factory unit that was in the car. Opening size on the Stant product was a good 20 percent smaller than the Nissan product... bought a new Factory Nissan stat. Dealer ordered it direct from Japan and it arrived within a week. Dealers in Canada can still order parts direct from Japan and we're fortunate to have a group of Nissan Parts Managers who all raced together during the 70, 80' and 90's and still are enthusiasts. Mots of the old Pro's enjoy nothing more than scrounging thorough the old manuals and parts Fiches and seeing what they can hunt down. Hint: For a Nissan 160 F thermostat, you may be able to find it at a Nissan Forklift dealer. The A series engine is still in production in fork lifts, and the A seriers thermostat is EXACTLY the same as an L-Series. I'll look up the part number for the Nissan 160 stat and get back to ya...

Reason why? Because Stant ( and other aftermarket makes ) have taken a shite nose dive quality wise since the 1990's. Out sourced all over the world and quality isn't the same as when they were made in the USA. Even their premium line Stants have big tolerance variations now. Problem seems to be the same for all aftermarket brands now. Aftermarket parts just seem to be made of junk these days and have been for a long time. About 15 years ago I stated seeing big fluctuations in thermostats from manufacturers I normally trusted. Venders like Stant and Robertshaw, that I'd used for decades. Fought a fluctuating cooling problem for quite a while on my Hillclimb/Track day Camaro. This was on a car that had more than adequate cooling and NEVER gave me any issues. Drove me nuts for a while. Long story short. It was the Stant line of thermostats I was using. Seems the quality control and tolerance for opening and closing points had been relaxed... a lot. This saved the bean counters money because now they had less rejects in testing. And what's 5 to 8 degrees here or there with todays modern cars that typically have Gauges that are purposely inaccurate so dumb arse drivers don't panic. ( Example: Typical Subaru engine temps can go up or down by 15 F and gauge won't even budge. Keep the brain dead drivers happy. ) Of course not being a typical driver I had decent mechanical water temp, oil temp and oil pressure gauges in the car. So a 5 to 10 F difference in thermostats opening temperature was easy to see. Solution was to switch back to factory GM thermostat in car. Temps immediately stabilized and thermostat opened and closed EXCACTLY when it was supposed too. Several years later when I sold the car to a buddy, he started experiencing strange temperature fluctuations. Car didn't overheat, just temperature range was varying from what it normally ran. Guess what. During maintenance, he replaced the thermostat... with a brand new Stant. Buying a new OEM GM stat instantly fixed the issue for him juts like it did for me. He took great pleasure in pounding that Stant product flatter than a pancake with a sledge hammer. Like me he had been a Stant club member for decades. Factory thermostat's, be it GM, Nissan, Audi, VW , Ford or Toyota still seem to be made of better materials with decent tolerances. And you can be darned sure that an NOS Japanese Nissan thermostat is going to be a hell of a lot more accurate than the aftermarket crappola available today. I buy a lot of parts from my suppliers and Rock Auto. One of the few OEM parts I insist on these dyas is thermostats. YMMV... and just my .02c

I've had the JB Water Weld on for about two years now with no leaks around the electrical terminals. Proper prep is essential. I ( or rather my mechanic/slave ) took the sending unit out, cleaned it thoroughly around the terminals with a Dremel and SS brush. Then applied the Water Weld epoxy to both interior and exterior surfaces around the terminals. Seems to be working so far....

I think that was one of my posts. Regular JB Weld will not work in the long run Constant exposure to fuel will eventually break it down. What does work is JB Water Weld product #8277F. This is a two part epoxy putty that is designed to be used Fuel Tank repairs ( amongst another things ). It is resistant to Petrol, Diesel, Oil, Hydraulic Fluids and most Chemicals. They call it Water Weld because it will set underwater. http://www.jbweld.com/products/waterweld-epoxy-putty

Just for giggles. I'm going to post up what I would run a stock L28 with triple 40DCOE's. Then I, going to E-mail Dean ( my buddy ) and see if he has the specs on his very well Tuned ( Specialty Engineering Tuners ) just to see how close I am bear in mind that you can juggle jets and Emulsion tubes and get nearly the same outcome. Juts some will be a little more " Perfect " than otheres.. Not saying this will be perfect... but just what I would choose as a starting point . 32 or 33 mm chokes. F16 or F9 emulsion tubes, 145 main jets, 175 to 185 air jets, 50F9 pump jets. Final tuning on a Dyno to get a smooth AFR curve. Ignition timing. Important; Independent runner manifolds like a LOT of low end timing. Static timing of 15 degrees BTDC. Total mechanical timing of 32 to 35 degrees all in by 3,500RPM ( Depends on fuel quality and cylinder head ) . If you can, run a Vacuum advance but use an adjustable vacuum pot. And additional 10 degrees of Vacuum advance hooked up to MANIFOLD vacuum. really perks up an Ir engine. Especially if it has a larger Cam. Just my .02c...

Once you have corrected float level. If you still find you are lean non Mid range and higher RPM's. 1: F11's have additional holes on the lower end of the emulsion tubes. This acts as an additional High speed air bleed. ( Fuel level drops as Booster signal ( RPM ) increases. ) Consider switching to an emulsion tube with fewer or no holes towards the bottom. An F16 E-Tube seems to be a good compromise. F9 should be even richer. Here is a link to an Alfa Forum article that compares F11's to F16's and F9's. http://www.alfabb.com/bb/forums/carburetors-fuel-injection-air-intake/102770-f16-vs-f9-emulsion-tubes.html#post601838 Here is another article mentioning a correlation of cylinder size to Emulsion tube selection. I would take this as a rough guide but it does illustrate why you could be so lean with the F11 Emulsion tubes. It's those extra bleed holes down low. Source Club Cobra. An L28 is 466.66 CC per cylinder. 2: 40 mm Webers with 30mm chokes are pretty danged small for an L28. That is going to create a LOT of booster signal and that strong booster signal will pull the fuel level down lower in the float bowl at high RPM's. F11's emulsion tubes have extra air holes down low, so this leans the mixture out too much. IMHO, You'd be better off going with 32 - 33mm chokes in the 40 DCOE or a 34mm to 36mm chokes in a 45 DCOE, Choke size should ideally be around 80 percent of bore volume for a mildly modified street engine or Autocross car. 85 percent for Race engines. Anything above 85% is strictly track use and kills Booster signal. . 40 DCOE's with 30mm chokes are very small for that cylinder displacement. Makes for good bottom end ... but starving engine for Air and Fuel above 6,000 RPM. 3: Main jet and emulsion tube size go hand in hand. Again, IMHO, 125 main jets are too small for your combination of parts. If you keep the F11's, you would have to go up quite a bit in size on the main jets. I'd start at a 135 main and you may have to go up to a 145 to get the WOT mixture correct. Your engine was way too lean on the top end. Just as an example to show the correct combination of parts.. I ran twin 40 DCOE's on a street driven, but heavily modified, Datsun 1200. It was my daily driver to work. 32mm chokes with 115 mains, 155 airs and F15 tubes . That's 115 main jets on an engine with 300cc per cylinder. But note the correlation of Emulsion tube to cylinder size in the above chart. F15's are the correct size for a Datsun 1200. F11's on a L28 are not. Mains are too small on that combo. The 1200 engine idled smoothly at 1,000 rpm. with a 280 degree camshaft ( Gotta luv IR manifolds ) was very easy to drive and would pull 32 mpg on the freeway. Dynoed at 120 hp at 7,200 rpm. No power below 4,000 rpm to speak of... because it was only 1171cc's... but engine drove like it had Fuel injection. No bucking, no snorting no flat spots. That is the magic of properly tuned Webers. You'd think it was a stock engine until it came on Cam... then all hell broke loose. Below 4,000 rpm it was a puzzy cat. ( I can't believe you can't type p****.... censored ) 4: The stumble from idle to mains is not typical. Actually I think you are referring to a stumble from the low speed circuit to mains... not idle to mains. Weber's are a 3 circuit carb with separate idle, low speed and main fuel circuits. I think it's just a matter of getting the tuning right. Again I think it's a combination of wrong emulsion tubes with wrong jets. My recommendations would be to start off with the basics. Change only ONE thing at a time and log results. It just so happens that we have a local fellow with a very well tuned stock L28 running triple 40 DCOE's. I'm going to e-mail him and find out his specs if possible. Once you are in the Ball Park, it is all fine tuning.... but I think your combination is just a little off. I have an idea in my head what I would select, but I don't want to make too many suggestions at once.

Castrol Super Clean is really good for degreasing. Will even remove synthetics. Just don't let it dry on aluminum. . Supposedly Bio-degradable too. Regarding pan bolts. I always clean them thoroughly, wash off any solvent with Brake Clean. Then install them with one drop of Medium strength thread locker.

Dang... I must have got the last one. Was a while ago... GL with search.

Thought this might help some people with 280Z and original dealer installed AC systems. Finding the correct replacement receiver for 75 and 76 280Z's can be difficult. If you have one with offset connections and the pressure switch on the top they are quite rare. Four Seasons part number is 33286. Found a supplier in Canada that has them in stock with the correct positioning of fittings. $63.29 CDN https://www.thewrenchmonkey.ca/products/auto-parts/four-seasons/33286/

You can polish the bores and Pistons using Crocus cloth ( Machinist Cloth 1000 to 2000 grit ). Use it with Brake Fluid as a lubricant. Do not use any Petroleum based solvents. Clean off with Brake Cleaner. As long as bores or pistons are not pitted in sealing areas you should be good to go. It often just surface corrosion that causes a sticking piston.

Yes, that could very well be an " Amplifier " for the speed switch as you mentioned. That would have to presume that the Speedo shown in firts post is a later model than a 71, As for the Z cars using separate VR's in each gauge, I have to wonder why they would have done that? Seems a more troublesome and expensive solution than using a single Instrument VR as they did on all most other models. A single Instrument VR were used all the way back on 16600/2000 Sports cars, 510' 520 PU's and on some model right through the 80's and 90's. It doesn't make sense why they would change the setup on the Z cars. Edit: But obviously they did... as the 620"s had the VR in the gauges ( Bimetallic vibrating points ) , maybe 720's as well. But then they went back to a single solid state single VR with the Pathfinder and D21 trucks and a lot of the sedans. Another question. Nissan parts catalog lists a " Shunt " in the " Meters " Parts page. Part #24845-N3401. Illustration #18. What does this do? Is it some sort of resistor that drops the voltage? Only from 73/08 to 75/07 ??? http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/meters Edit: I've edited my Post #6 above to correct inaccurate and irrelevant info.

Here is a copy of the RatsuNet wiring diagram that shows the Instrument VR. ( Lower right hand corner with Temp and Fuel gauge ) Not usually shown in wiring diagrams because the part was not always available separately as I mentioned.

Yes they did. On all models of Datsuns . ( Edit: Correction... Apparently not on all models according to references below ) If you read the complete article from Ratsun.net you will see a full color diagram for a 1969 Datsun 510. The Instrument VR is shown in that. Datsun 510's 240's 620's 520's and 1600/2000 sports cars all had Instrument voltage regulators. They were used from the 1960's right through the 1990's. If you had a magnetic coil operated temperature gauge or fuel gauge they all had them. Ford's, Chevy's, Toyota's etc, etc. The magnetic coils were designed to work with with 6 to 9 volts maximum. Not all the wiring diagrams show the Instrument VR because it usually came as part of the Speedo gauge. Same with the Parts manuals. I'll have to have a look at my 1976 280Z Factory SM to see if it's shown. Some guys retrofit a Ford Mustang VR because they are dirt cheap. But you can easily find wrecked Nissan Pathfinders and Pickups on the Boneyards. Sentra's had them available separate as well, but the part number is NLA. Both the 24866-54A and 24866-07G05 are solid state, where as the early 70's models were a vibrating coil type very much like the alternator V/Reg. Here's a partial listing of some available and discontinued Instrument VR's. Not the ones that say Knob-Meter as a description is likely a misprint. http://www.courtesyparts.com/?p=catalog&mode=search&search_in=all&search_str=24866

Integrated Engineering makes a Surge tank that includes Internal mounting for an Bosch 044 or similar pump.. Single or Dual pump versions available. Lots of VW/Audi/Subi guys use them. You can keep the stock 240Z tank, Return lines can route back to the surge tank. http://www.performancebyie.com/ie-submerged-044-billet-surge-tank

Can you take a picture and post? Only thing I can think of down there is the Evap system flow guide valve. It should have two small hoses. One goes to the Crankcase breather tube coming out of the block. The small nipple can be capped off at the Crank breather tube, and you can toss the rest of the parts.. Illustration #57. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/emission-control-device

Original 1970's Instrument Voltage limiters are next to impossible to find. A Voltage limiter from the 1980's and 1990's can be retrofitted. 24866-54A00 is a popular model. You can still buy them from dealerships or find them in Bone Yards. Pathfinders and Trucks use the 24866-54A00. You may find the newer V/Reg has three wires. Extra black wire is for a dedicated ground. Old 1970's style grounded through case. Edit: 24866-07G05 may be a better choice. Cheaper and only two wire