Setting timing

jeep_man_401

OK, I should know this but tell me if I'm right. 111!!! If the timing is a little jumpy at idle (EVERYTHING is new) it's probably the unstable idle from the big cam (over 300 dur.) I get a more steady light (timing mark) with the light connected to the coil wire. #-o Now, if I remember right, that was the case when we where at the dyno, we timed it with the light to the coil. That would be more accurate than on a jumpy #1 wire right? Anything wrong with that?

ironman_gq

is the light inconsistant or is the timing mark just wandering? If the lights inconsistant you might have a missfire If its wandering its probably the advance springs starting to kick in. Try to lock out the timing advance and see if the wandering stops.

Mudrat

ironman_gq wrote
is the light inconsistant or is the timing mark just wandering?

Yes to both in my case - but does it LOOK inconsistant, becasue of misfire or wandering because of timing?? How does one tell? (And I DO have this problem)

ironman_gq wrote
If the lights inconsistant you might have a missfire If its wandering its probably the advance springs starting to kick in. Try to lock out the timing advance and see if the wandering stops.

How does one 'lock out' the timing advance?

AMX69PHATTY

Would think if timing light pick-up is placed on the Coil wire it would "flash" with the firing of every spark plug, instead of just with the firing of the #1 cylinder :-| Inconsistant light would think misfire. Bad signal from Phat plug wires ? Mark "wondering", would also look at weights starting to come in. Wouldn't have to "lock-out" the mech adv., just temporarily install some heavier mech adv springs and see if it "calms down" the timing mark under the timing light at idle. I look at the initial timing setting, but the main thing is to set the Total Timing Advance at say ~36 deg with mech adv all the way in, which is determined by the weights and springs. It's not easy to get weights / springs that give zero adv at idle and full adv by ~3000 to ~3500. Mine is all in by 3500, and starts advancing right at idle, or even actually causing some mark wondering at idle cause they're starting to come in, and as they do the slightly increase idle speed, which make'em come in a little more, then idle drops back off, and they drop back. I've always focused on the total timing advance, and the initial ends up being whatever it ends up being.

jeep_man_401

I think mine was just not getting the signal right and idle quality. After messing around I got the timing steady and the motor responds nice. I am running the dissy locked out...so I know that wasn't the problem. (No springs, weights or vac) I am running the MSD 6AL with the programble timing computer. Works good. But we timing it on the dyno and of course I couldn't find the sheet with the last timing on it! #-o I've settled on about 20 at idle and a total of of 37 or so if I remember right at 3200RPM. The computer can only back the timing down 20 degrees. So you set the timing advanced and then bring it in with the computer...but you can comtrol when it starts, how fast it comes in and how much to bring in. It even has a starter retard and a "high speed" retard with differnent chips. But now it is rock steady at idle again...running alttile rich though...but thats 2 4bbl carbs though. :lo1l: