Zed Head

Didn't mean to be a downer. The topic comes up often and generates lots of discussion. Here's an interesting thread, in a similar vein, with lots of good insight - http://forums.hybridz.org/index.php/topic/102085-200-whp-na-build/ The short stroke of the L24 crank lowers your displacement also. The calculator shows 2.569 L. From what I've read, the lightened flywheel alone will make it feel "revvier", and some moderate flow work on the head will actually make it more rev happy. My limited knowledge...

Another clue would be to remove the water pump/alt belt next time it's making noise, then start the engine and listen. You'll just run off battery power and the engine won't overheat in the time it takes to see if the noise is still there or not.

According to this calculator (which seems to be pretty accurate) your piston will protrude out of the bore by 7.1 mm. http://www.ozdat.com/ozdatonline/enginedesign/ RB26DETT pistons look close but will give you an 11.25 CR.

Probably depends on if the corrosion is on the piston seal surface or not. I had a tiny little scratch in the bore of one of my calipers from the PO's rebuild (I think he dragged the dust cover holder wire across the surface) and the brakes worked fine but the caliper leaked fluid. Fully rebuilt calipers are surprisingly cheap. I think I got one for about $30 at OReilly auto a year and a half back.

Check the restriction in the block for blockage. Maybe you have low flow/pressure to the head.

I've seen it discussed over at Hybridz. The main concern is whether or not there's enough flow through the orifice in the block to get equal oil supply to all of the holes. I guess you could get an imbalance, although it doesn't seem likely. Some say there's plenty, others drill out the restriction in the block to be sure. You might search around over there to get a better idea. Why is the cam shaft being replaced? `

In #6 you said the bar was still plugged. Can you dig out what ever is in there? Might be informative. The holes on an internally oiled cam shaft are just as likely to get plugged, I believe. Pretty sure I read an account on another forum about a plugged internally oiled cam shaft causing some destruction.

Have you actually seen the holes in the cam shaft at each lobe's base circle, or are you assuming from the service manual. A picture would be interesting.

That's a very good point. One could probably estimate a likely range of location on a single cylinder's compression stroke and get a fair idea of where the other five would end up. #1 location - 120, - 120 more, - 120 more, etc. Or you could just eyeball the cam shaft, after multiple shutoffs and see where the lobes end up. That might be enlightening. We're not trying to tear down the concept, just doing some process development, to help people avoid some pitfalls. Plus it's just a good reason to BS about cams and what they do, and practice reading cam cards (which can be confusing - to me).

Leon, you've corrected a statement I made in a different thread. I said 4% of the time (30 of 720 degrees) there was overlap, according to the cam specs. in the FSM, but I neglected the other 5 cylinders. 6 x 4% = 24%. Actually 6 x 4.2 = 25%. 25% is pretty good odds that there will be some leakage through the intake manifold to the exhaust. Of course, this assumes correct valve lash settings. Looser lash would reduce the odds. You should also consider blow-by past the rings and valve seals. Still a test worth doing if you're stuck.

There is something not quite right about the "solution" in Post #10. The thermotime sensor only controls the cold start valve, which is only powered when the key is at Start. So the thermotime sensor should have nothing to do with your backfiring problem. "Off-idle" leanness could be caused by the TPS not indicating "idle" to the ECU. According to the FSM, Engine Fuel section, there is an "after idle" enrichment. It appears this is added by the ECU when the TPS switch moves from idle to the middle or part-throttle position. The diagram is on Page EF-11.

If you get a filter with 1/2" barbs, everything would work correctly, right? The inlet on your fuel pump is probably 12 mm or 1/2" (depending on the pump). Have you compared the fuel pump inlet size to the fuel tank outlet? 1/2" from the tank (actually 12 mm probably), 1/2" to and from the filter, 1/2" inlet on the fuel pump. The outlet from the tank is the big one and the return line from the engine bay is the small one (5/16" or 8 mm).

This guy got 192 hp with carbs and fairly mild components. The results are shown in Post #41. http://forums.hybridz.org/index.php/topic/100267-green-machine-gets-a-new-motor/page__st__40

Nothing in your picture looks obviously like a "vent hose". To me anyway. If you mean the vent line from the gas tank to the charcoal canister, that line needs to be open.

Check out Post #6 in this thread - http://forums.hybridz.org/index.php/topic/103494-broken-studs-on-turbowhat-to-do/page__pid__969336#entry969336 If I ever need to drill out another manifold stud, I'll try to build something like it.

Under the dash at the end of the brake pedal. If you have flexible fingers, you can do it without removing anything, just loosening the lock nut. Lots of good pictures and a description of the procedure in the FSM, Brakes chapter. http://www.xenons30.com/reference.html If no one has messed with the brakes recently, it could be something else. More details about the recent history of the car would help. Good luck.

Sounds like you have the pedal adjusted too tight and it's keeping the pistons in the master cylinder from retracting all the way. The fluid gets hot and expands, putting pressure on the brake lines, cylinders and pistons, because the fluid can't get back in to the reservoir. Did you adjust the brake pedal recently? Loosen the rod going in to the master cylinder until there is some play between it and the brake pedal.

Did you fix your fuel pressure yet? One very important reason the propane test didn't work might be because there is no leak. You might be wasting your time. The a-wipe might have been right after all - "Some asswipe told me one time to open up a propane torch and wave it around for intake leaks, this is complete nonsense."

This topic is really more about how to interpret the FSMs. Which is a pretty interesting topic anyway. I don't that that you can determine "reason" from the FSMs. Fun to guess though. Food for thought - how is the fluid level determined and what should it be when climbing the Rockies? The same for descending. How long can you climb the Rockies before needing to turn around and back up the mountains to re-lube the dry parts or to let the foam subside? Do Zs in San Francisco suffer more lubrication related transmission problems than Zs in Illinois? If it was super-important, there would be a sight-glass or dipstick installed to verify correct fluid level range. Like in an engine,where it is super-important, but there is still a one quart safe range. Also, Nissan surely would have put one of those cartoon guys in the FSM, sticking his finger in the fill hole to check level. No cartoon guy - not that important. (p.s. I'm kidding)

You should measure and set the static timing, and confirm that the vacuum and mechanical advance of the distributor both work correctly. The later 280ZX distributors are designed to run with EGR and have a lot of vacuum advance. You might have to dial back the static timing to avoid knocking at partial throttle (where you'll be driving for economy). The first thing you should do is determine exactly what distributor you have and measure and set your static timing. The 79 ZX has a pretty good setup, the later ZXs get more complicated. What year did yours come from, or what is its part number? Your jumpy timing at idle could be because the vacuum advance vacuum hose is direct to the intake manifold instead of a ported source.

Probably dirty battery terminals. The engine is running on battery alone. Turning on the lights heats up the dirty terminals enough to break the connection - no current from battery or alternator, engine dies.

Don't' forget to clean your battery terminals when you have the battery out. Dirty terminals cause a lot of problems. I've known about terminals being a potential problem for many years, and I still came close to buying a new starter about a year ago, before I realized it might be the terminals, cleaned them up, and got back to normal.

When was the last time you looked under the boot? It could be a pool of oil that's taken years to build up in there. As the shaft moves back and forth maybe it's been moving a tiny amount of oil one way more than the other. The seals aren't perfect. Just a possibility. You might dry it out, drive it and see how fast it fills up. Count how many shifts you make so that you can determine an oil removal maintenance schedule! On the other hand, it's a good reason to take something apart that hasn't been messed with for a while.

It's described in the FSM, Engine Electrical section. I don't know where it is on the cars with ammeters. The L pin in the plug should show 12 volts when the key is turned on. If it doesn't, something's not connected right. The "warning lamp", wherever it is, should go on when the key is On but engine not running, and off when the alternator is charging. Edit - my slow typing got me again. Stevej, the FSM does show a "warning lamp" in the regulator circuit. Maybe they're using the brake check warning lamp for voltage? Either way, the L pin should have 12 volts, key On, engine not running.

http://www.classiczcars.com/forums/showthread.php?44115-Brake-Cylinder-Retaining-Shim&highlight=wheel+cylinder+clips