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So I replaced the distributor/intake manifold/carb etc. since the previous owner was more concerned with performance versus everyday driving. Upon startup, the engine runs, but it is bit rough and occasionally spits. Since I am by myself, would like to have it running good enough to throw a timing light on it but by the time I get out of the car it dies. Looking down on the distributor, does tuning clockwise advance or retard the timing? I thought I had it roughly 8 degrees BTDC - should I retard the timing a bit or advance it?
The previous owner was on the right track. They go hand & hand.
Those timing numbers are old, smog, help me pass my emissions test crap.
Bump up the timing a bit.
The rotor under the cap turns C.W. So, turning the dizzy C.W retards timing.
C.C.W. advances.
Make sure your vacuum ADV canister is plugged into full manifold Vac and not ported vac when you are done tuning.
Last edited by HeadsU.P.; May 10, 2022 at 04:45 PM.
Clockwise retards it. 8 degrees is not enough. If it is running rough, loosen the clamp just enough to be able to change it with the engine running. Try advancing it counter clockwise. The engine will tell you if it likes more timing. Listen to it. The first thing the dealers did when they received these cars from the factory was advance the timing from the ridiculous specs on the emissions sticker. I am running mine at 16 (at the top timing mark on the tab). If this does not stop the rough idle, you have other problem(s).
Agree you should have more than 8 degrees initial. And yes run manifold vacuum for your advance.
But thinking it really should at least stay running at 8 degrees.
Spitting, Poppin? Bad plug wire or wires? Fouled plug?
Just had the carb rebuilt so the idle speed and mixture should be good. I'll turn the distributor a bit CC and see how that works. It ran when I gave it gas, but would not idle on its own and it spit once or twice. Since I replaced the non-tach drive HEI with a tach drive HEI, I set the distributor to fire at 8 degrees BTDC, but my rotor to the #1 plug alignment was of course by eyeing it up so that might have been a tad off itself. I connected the vac advance to the non-ported advance connection so that should be OK. Some pics are below:
Yes, that is a temporary choke rod made from #10 copper wire, at least until I get the Edelbrok divorced choke setup.
It'll probably stay running at idle if you plug your distributor vacuum advance into a manifold vacuum source. Then you can use your timing light to do the rest without a helper.
I have used the idle speed screw to raise the RPM long enough to get in there and set the distributor. I pull off the vacuum advance hose and rev the engine to set the distributor at 36 degrees at the top of the curve. Lock the distributor back down, recheck the timing, reconnect the vacuum advance, then back the idle screw back down to normal speed.
"Just had the carb rebuilt so idle speed should be good".
Thats not something than can be done on a workbench. The under-hood sticker idle info is factory suggestions.
You can set, not only the mixture but the RPMs to YOUR liking, not what someone else wants. Especially on an Auto trans.
Constant stalling is more wear & tear on the batt / starter and in general, is a PITA.
Looking at the carburetor, The port that the distributor is hooked to,,,,, front, bottom, driver side of the carb, is that full manifold vac or ported vac?
Looking at the carburetor, The port that the distributor is hooked to,,,,, front, bottom, driver side of the carb, is that full manifold vac or ported vac?
I thought that was manifold vac - am I wrong on that?
Update - skootched the distributor a bit CCW and restarted the car today. She started right up and idled very smoothly - no spitting or stumbles, so I'm getting close. Appears to be a bit down on vacuum and when it came off the fast idle it didn't want to idle by itself so
I'm going to pull out the timing light and set her up the way Lars paper indicated. I need to apply the timing tape later since I don't have a variable timing light, just the static version. Even better news is I now have a heater as i had replaced the entire heater core earlier last year
but never hooked up the hoses.
Advance or Retard Timing
I've been tricked before by looking at a diagram.