So, first of all, i've been gone from the car circles for a long time for certain reasons. Have forgot most what i learned about carbs and timing.

 

Problem: last summer, i broke my distributor. Yes, it went broken. The collar that holds dizzy on place (with 2 10mm screws) was bent and eventually dizzy started to wiggle, so forth destroying all screw threads that were holding it to place. SO. I replaced it with similar kind of oem 240z distributor (no-points, custom made) and i just CANT make it run nicely.

 

I have 3 SK/OER dual sidedrafts that were tuned last summer. Havent touched them since. I dont remember the basics of timing, but i have timing gun with igniton advance setting.

 

Tell me what are the correct numbers for proper timing on 3 carbs. We tried every combo. It sometimes idled super smooth, then when rpms raised, ran like $^!#.

 

In two weeks we have major car event here, i just need it to be done with before the show.

 

Thanks in advance

Seems more like an ignition/valve problem to me. The engine is shaking to much running stationairy.

One of my Z-friends suggested that with L24 timing (with triples) would be better in 8-9 degrees initial... any opinions on that? I shall try to tinker with the timing ONE MORE TIME.

Edited April 22, 20159 yr by Reverend

Non-emission L24  engine is spec'd at 17degree initial.  The emission version is 5 degrees.

 

Check page ET-3 of the L20A, L24 Service manual.

 

 

You should be able to work anywhere between 5 and 17 degrees so long as you don't over shoot 36-38 degrees at full advance ~3000 rpm.

 

 

The faster your motor will advance after 1200 rpm, the better your motor will pull so long as you do not ping by advancing too quickly. (The weights, springs and canister on your distributor take care of how the timing advances from initial to full).

Something very strange has happened!! Yesterday was the first day in week i had time to tinker the car, so i started with my long planned speedo change. I had taken the old off beforehand, now was time to put the "new" one in. Well i succeeded in that and was planning to go to test drive to see if it works. Well i did not have my tachometer on and for some crazy arse reason the car did not start. Starter turned but engine did not start. I was mezmerised. Well decieded to check that engine problem later and put the tachometer back on and connected all the wires. After that car starts...OR TRIES. For some reason everything has gone straight to hell. It barely starts, stumbles like crazy, backfires from carbs and exhaust, engine shakes like crazy and only stays on if i hit pedal to the metal but i do not dare to do that, im afraid something has gone horribly wrong. I tried to tinker the timing, but no matter what i do, its just $^!#. No matter how retarded or advanced, it barely starts. Tried with 2 different distributor caps, 2 coils (another one was a MSD Blaster 2, but it apparently does not like the ballast resistor so it did start but died of instantly). Also checked plugs, they were all okay but equally black and wet. I checked all idle mixture screws, they were 1.75 turns open, i dialed them to 1.5. No change.

Heres couple videos me trying to start it.

 

 

https://www.dropbox.com/s/x8rdlchur2m56qt/20150426_204707.mp4?dl=0

 

https://www.dropbox.com/s/s5g6jzh2382diit/20150426_204532.mp4?dl=0

 

I've already stressed her out so many times that i did not dare to press the pedal and so you dont hear when she's actually running...wich is just plain scary.

 

I dont know what to do.

The reason it didn't start with the tach out is because the coil wire runs thru the tach to give you a reading. It's a current driven tach, so all your ignition current goes thru it. when you pulled your tach you disconnected your ignition.

When it didn't start the first time, did you mess with anything before you reinstalled the tach?  Plug wires, maybe?  Kind of sounds like the firing order is reversed.

Plug wires are in correct order, did check that out too. It sounds a lot like firing order is F-ed in bigtime. Is there any major wires inside console that i could have messed?

Id go with madkaw, seems you have no voltage to the coil for ignition now...

Could he have damaged the circuit or coil with the tach out?

I don't think that's likely. The tach is between the battery and the coil.

 

With the tach not installed, the entire rest of the ignition circuit is stone cold dead. No power at all and no energy to cause any damage.

 

In other words, the points are opening and closing, but there's no power to switch.

Neither of those Dropbox videos will play on my system.  Don't know if it needs a sign-in or what.

 

He says that it runs now, but very poorly, so the tach and igntion system seem to be powered.  Considering that the plugs were fouled when there was no spark, I would install new, clean plugs, set everything back to where it was, and try again.

Plugs are almost brand new, i cleaned them all and tried again with no change. I have gut feeling that it has something to do with spark but i just dont know what it is. Can i measure my coil somehow, that it is operating correctly? We have major car event coming in 4 days, the first of may....