Might be a dumb question BUT....

Might be a dumb question but i won't know until i ask, so ....

When i put the car in reverse or drive it idles WAY down and will die, could it be or does it need a bigger vacuum line. We have it hooked to a small line on the carb But my big line is open if needed?

Thanks for the help in advance

 

More details please.
Is it a new deal,old deal?
Cam specs?
Type of trans and converter?
Carb?
Timing?
Va*** line size shouldn't matter at this point.

 

New deal.. new ****** and new motor
Cam 489 lift 220 dur - 230 six w/ th350 and a stock converter
new Holley 600cfm
timing is set at 8degree's advance

Seems to get better when it reaches temps close to 180, so i may just not being patient enough with her

 

Is the th350 supposed to have the idle speed set while you're in drive like the Powerglide? And if so, did you have it in Drive when you set the idle speed? I've got a 235/PG and had the same problem the first time I adjusted my carb.

Even adjusting it right, it'll need a little extra juice when the engine's cold. That's why the old BC carbs had a fast idle cam.

 

that cam is big enough that you should be running a 2000 stall converter, at least...probably more because the engine is so small.

The size of the vacuum line has nothing to do with it.

As the Cpt said, play with the idle adjustment, maybe play with the timing curve too, and maybe try connecting the vacuum advance to a non-ported vacuum fitting (if it's connected to a ported fitting now). "ported" means that it only gets vacuum when you open the throttle past idle.

 

Tony, Just a new guy but, you may have a vacuum leak going to the modulator on the ****** or the modulator itself. You probably already checked it but I just want to help if i can.
Rich

 

It should idle consistently at around 160*+(but warm it up good anyway before adjusting).
The carb seems a little large(a 500 would prolly be better) but not enough to cause it to die at idle.
The cam doesn't seem big enough to cause idle probs with the stock converter.(this a borderline deal)
Warm it up good and set the timing(8* at idle seems a little soft) at say around 36* Total at around 3000 rpm's (disregard timing at idle for now) and set the idle speed(about 850-900 rpm) and mixture screws at this point.
Now check initial timing.If still 8* make sure that the vac advance is hooked to a source that has vac. at idle and check initial again.
It should have around 12ish+ degrees initial at idle.
If once the motor is warm and timing and idle speed screw is set and the mixture screws don't seem to do much and it smells rich at idle and maybe continues to get richer and idle goes slowly downhill,it may have a bad power valve,Particularly if it backfired during start up and run in.(a common Holley prob. with older Holleys with no backfire check valve).
If mixture and idle speed stay consistent in neutral(park) and it still continues to die in gear it may want a mild converter.

 

Maybe, maybe not....Chevy put rather high stall converters behind small engines, stock. Remember the Vega th350 converter? it would get about 2500 behind a small block iirc...

 

Dude these are cold blooded *****es unless ya run em way rich! I do not recommend running them way rich,however,insuring that you have adequate heat to the base of the intake manifold and insuring that she breathes at least 120 air till fully warmed up will go aloooong way in driveability. People put headers on inliners and do away with the heat to the base of the intake manifold and shoot themselves in the foot every time! Tom Langdon makes an aluminum plate that routes engine coolant through it to keep the base of the manifold hot,to aid in fuel vaporization and stop fuel puddling. Remember the old ugly air cleaner that had the trap door on the end and the pipe to the exhaust manifold? G.M. did that so it would fairly quickly breathe hot air off the exhaust manifold to also aid in fuel vaporization and in inclimate weather stop carb icing. If ya run a Monojet carb ya can remove the idle channel restriction tube and slighlty,and I mean slightly enlarge the orifice tip at the bottom of it to fatten up the idle circuit a bit,open it up with a welding tip cleaner about.003 more,you will have better adujustability on the idle mixture control screw.

 

Squirrel you have a point.
But wasn't the stall to make it easier for the little motor to get things moving more than the quality of idle?
I mean big trucks and motor homes traditionally have a looser convert too for that reason don't they?

 

Thanks Men, looks like i have some things to try....

i hate old cars....i love old cars...i hate old cars... i love old cars...

ya'll ever feel this way, especially when thrashing for Round up and you've had just enuff sleep to keep the blood flowing somewhat.

3 days left gotta go