Stall Converter Question.....
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Stall Converter Question.....
I'm at wits end....engine idles ROUGH in Drive...like it has a big cam.
SPECS:
New 350/290hp GMPP crate engine;
new Holley 670 Street Avenger;
new MSD HEI with new MSD wires and new AC Delco plugs;
Engine's full advance 36* @ 2400 RPM; Initial timing: 18*
Vacuum at Idle (in Park) 15"...in Drive 10" (according to GMPP, this is normal)
Completely checked for vacuum leaks...none found;
Compression check (all 8 cylinders) between 120-125psi each;
At cruising speed: smooth, no backfires, runs strong;
Acceleration from a dead stop: Strong, no hesitations, no bogs;
Changed carbs (thinking maybe it was the carb)...no changes noted.
Only thing I find odd (other than the rough idling) is that for me to get 650 RPM in Drive, I have to set the RPMs @ 1100 in Park.
It currently has the stock transmission (automatic)...do I need to go to get a higher stall converter? Will this solve my idling problems?
SPECS:
New 350/290hp GMPP crate engine;
new Holley 670 Street Avenger;
new MSD HEI with new MSD wires and new AC Delco plugs;
Engine's full advance 36* @ 2400 RPM; Initial timing: 18*
Vacuum at Idle (in Park) 15"...in Drive 10" (according to GMPP, this is normal)
Completely checked for vacuum leaks...none found;
Compression check (all 8 cylinders) between 120-125psi each;
At cruising speed: smooth, no backfires, runs strong;
Acceleration from a dead stop: Strong, no hesitations, no bogs;
Changed carbs (thinking maybe it was the carb)...no changes noted.
Only thing I find odd (other than the rough idling) is that for me to get 650 RPM in Drive, I have to set the RPMs @ 1100 in Park.
It currently has the stock transmission (automatic)...do I need to go to get a higher stall converter? Will this solve my idling problems?
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
Your centrifugal advance probably starts at less than 1100 rpm; therefore when you put it in drive, as the rpm decreases some of the centrifugal advance comes out, which in turn causes still lower rpm. Try some more preload on those distributor springs so that the centrifugal won't start advancing until 1,000 to 1,200 rpm.
A smaller (looser) torque converter will help too.
A smaller (looser) torque converter will help too.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
I'd play with the distributor as recommended by others. With a mild motor like that I really don't believe you should need a looser torque converter. Good luck- I'm sure you'll get it figured out soon.
