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

Are the valve clearances all good ?

I've set valves last summer, but might as well check them. I swapped those jets (for shitz'n giggles) and no effect.

 

This is the current situation:

 

-Timing @ 13 degree

-Idle mixture screws 1.5 turns open

-Runs super rich and stumbles and sneezes if idle is reduced

-Consumes fuel like crazy

-Idle jets are "50/100", i think thats 50F9

Too much fuel consumption and dark plugs are caused by:

 

jets too large

fuel level too high

fuel pressure too high

 

 

Seems like we have been here earlier. Start from the basics again.

I made a small tool from transparent pvc pipe, made mark on 29mm and 31mm and measured. First 2 carbs had exactly the same amount of fuel (29mm), rear one had tad over 31mm. I dialed it down but even after full turn, it did not lower the fuel level to 29. Fuel level screw on the last carb is over 2 threads higher than the first 2. Is that normal? Here are couple videos, this first one is taken right after i started it, it raises rpms well but you can hear that the idle is far from nice. It feels like its not running on all cylinders when i took it for a spin, after few mins, it felt better, but not normal.

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_194615_zpsgfjnfec5.mp4

 

This is just a test how it sounds inside, too bad on this you cant hear the burbling sound it makes when idling.

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_195141_zpssmuhj8ya.mp4

 

On this last one, engine is almost fully warmed and i slowly raise rpms. Im quite sure it spits out from the last carb. Tell me your opinions!

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_195719_zpsqvdavzzy.mp4

 

I'm also worried about the engine shaking on idle, it shakes a lot.

 

Just reviewing the thread:

 

I just looked at the vids for the first time.  nice stuff

 

I see throat #3 spit 12 seconds into the first video when the rpms rise. Is this the throat that had the main jet separate (mentioned above)?

 

Also, the return line connected between carbs 2 & 3 could be causing the different fuel levels in carb 3.  Try to get a "T" on carb 3 and pull the return after that one. In the interim, you could try closing the return at the T between 2 and 3 so that there is no return to teh tank.  If your fuel pressure is ~ 3psi you should be fine for testing.

 

You should also spray starter fluid around all of the carb to manifold spacers to make sure no leaks are present.

Edited May 2, 20159 yr by Blue

 

Of course it's "possible" that all six plug wires got damaged at the same time, but it's so unlikely that I'm comfortable saying it's statistically impossible.

 

 

There is a Vulcan amongst us!

Live long and prosper.

Fascinating.

::

Fuel pressure is way more than 3 psi, like 6 or 7, if i drop it any more, it starts to stumble like crazy...

Maybe check your fuel pressure gauge?

 

Can you block off the return fuel path (dead-head configuration) and set the fuel pressure to 3.5 psi and see what happens?

 

This is the dead head config:

 

Edited May 2, 20159 yr by Blue

I think i know why the fuel pressure gauge showed crazy numbers. I hooked it to the fuel line such way that it was at the "end" of the line, so no fuel would pass it. I need to get T-shape connector so i can allow fuel to travel pass it and measure the pressure then. OR just get a regulator with gauge..

Hmmm. Another contradiction. It seems that carbs need craploads of fuel to run on idle and cruising speeds, but they starve when revving over 4500 rpms. Carbs sound like machinegun (popopopopopopopop) if i go over that...???

Dead head and set fuel pressure to 3.5psi. You can then focus on the carbs and not worry about fuel.

Hmmm. There is problem at cylinder 6. When i was driving, it felt constantly like its not running on all cylinders all the time. This morning i started it, felt and sound strange. Took of cyl nr 6 plug off, and it sounded exactly the same. SO nr 6 is not working. Its getting fuel as the plug is wet, tested plug and it gives spark... Valves? I have to do compression test as soon as possible.

Edited May 9, 20159 yr by Reverend