tired of it

[dero]

well as some of u might remember my last problem was well what i thought at least was the distributor, well i converted over to a complete electronic ignition, 73 distributor with ignitor set up with flamethrower coil, anyways i put it on, car still wouldent run but sparked really hot, so this spring break week i had off i pulled the timing cover and everything else u have to in order to get it off,re did the timing chain because when the engine was built it got put together backwards, on the exhuast stroke instead of compression stroke, so i get that correct and adjust all the valves put everything all back together (finally) sprayed the su's with some engine starter fluid and started it.........nope dident start, messed with it and got it to start somewhat, but now it seems my SU's are the problem as they dont respond at all when u hit the gas pedal, only way i found to rev the engine is to put rags in front of the carbs and block them and the engine will rev up, when you take the rags off the engine will go back to idle'ing crappy. lots of smoke out the muffler, occasional carbs backfiring smoke , anyways i dunno what all that means, still learning about SU's. oh yea the front timing cover is leaking oil like crazy.so i guess now im back to where i was earlier this week and im going to have to buy a new timing cover gasket and pull everything apart again. im just kinda dissapointed in the z,i really cant afford to be replacing part after part in the first place and then getting no satisfaction of driving it and having no car to drive, out of the 10 months ive owned it, its ran for about 2 and half. im just fed up with the z, all i do is put money into it, im starting to think about pulling the l24 and parting it out and saving up for a v8.

[JEFF]

Do you have a compression tester? Sounds like the compression may be a little low. Was the car running really good when you bought it? Change the fuel filter ($3.00?) and take the rubber hoses off the bottoms of the carbs clean/replace them - besure that they are very flexable. Take the tops off of the float bowls to clean them out. Try these simple things and you may be suprised at the results.

P.s. - parting out a L motor is not easy/fast because the shipping charges - The carbs might sell but will not get much in need of rebuild.

- Jeff

[Ed]

I'm having a mental block right now so someone help me.

Dero behind the timing cover there is a shaft that goes from the crankshaft to the distributor. On the lower end is a gear with teeth and on the other end is a flat screw driver looking tooth that turns the distributor. Make sure that this shaft is properly set. One tooth off in either direction will produce the symptoms you are describing.

[Ed]

Hang in there!

[tanny]

Even though I reassembled the distributor EXACTLY as described in the manuals(I think the tang was supposed to be at 11:25 or something), it ran exactly as you described. I had to advance the drive gear one tooth and it ran perfectly. When correct, the tang looked like it was in the 10:20 position. Guess it's a matter of interpretation and my thick glasses. To see if yours is set right, disconnect the coil wire and have someone turn the engine over while you're checking the timing with a timing light. Even at these low rpms, you will be able to tell if you are too advanced or retarded, and if off, pop the oil pump and readjust the drive gear. Hope it's this simple. Good luck.

[dero]

so this problem isent carb related?

[tanny]

I guess if the engine idles well with rags in the throats, the distributor drive must be installed correctly. Don't know anything about SUs but if you have to stick a rag over the throat at idle, which I believe would be richening the mixture(on webers at least), then this would indicate a too lean idle mixture. That's the limit of my lack of expertise on SUs. Someone here should be able to figure this out.

[JEFF]

UNLESS...... The cam to crank timing is alittle off. The same would hold true - What i mean is that by holding a rag over the carbs you are putting enough gas into the cylinders to fire the engine even if the valves are opening early. If they are opening early the amount of vaccuum created by the pistons down travel would be reduced below normal(reducing compression) - thus the rag over the carbs would force the vaccuum that IS there to suck a little more gas than it would without the rags.

If the valves are opening late the vaccuum is started before the valve opens, that makes a sudden large 'gulp' of intake when they do open. If they open late they also close late, letting some of the 'intake' out before the valves close( reducing compression).... thus the rags over the carbs would cause the intake of air/fuel to be richer and still fire even if some gets out early.

A compression test will show you if it is a valve timing problem.

Do the test twice - FIRST with normal cylinders and all plugs removed - SECOND - with about 2 squirts of oil from a pump can in the cylinders. If the compression goes up with the 2nd test the problem is not valve related. If the compression tests show the same readings the valves are the problem. Timing or leaking.

*A leaking head gasket would show the same as leaking valves/valve timing off except that it would be in only 1 or 2 cylinders.*

- Jeff

[dero]

ill do the test befor i rip the front timing cover off, and post back, ill prolly get around to it somtime within the next week......

[240ZX]

This sounds like a problem I once had with my 240. I was getting pretty frustrated with it, as you can imagine! It was eventually discovered that the distributor advance assembly was shot. The engine would run perfectly at and above full advance but would not idle properly. The thing that was so frustrating to me was that I had tried three different Nissan electronic distributors and they all worked the same.....like crap. (Note: these units were not purchased from Nissan, but were remanufactured units.) So, I finally broke down and installed a Mallory Uni-lite distributor. All is well now and my 240 purrrrs like a cat. This may not be your problem, but at least concider looking into the distributor advance assembly.

[beandip]

Hang in there, the rewards are around the corner. When she is running right you will be happyer than a pig in sh$t. One thing that you must considr you are infected by the Z and there is no cure. These kind of things can get to be a bitch but it could be the same way with a honda and when it was cured it still would be a HONDA . Now that is depressing, Hang in.. all the best . I think you have good advise here. Gary:classic:

[Brett240]

to check if the oil/distributer pump shaft timing is correct put NO 1 piston on Top dead center, then remove your dizzy. get a really thick screw driver and lie it inline with the blade on the oil/dizzy pump shaft. the screw driver shaft should just NOT cover the two bolt holes that the distributer bolts go in, the bottom of the screw driver should be towards the front of the car.

now this makes sense in my mind but reading it back looks pretty complicated, hope this helps.