1975 Still Sluggish
Thread Starter
Racer
Joined: Aug 2005
Posts: 377
Likes: 3
From: Northville MI
1975 Still Sluggish
Ok; I’ve done with the Plugs and Plug Wire replacement on my original 75 vette; also did all the belts while I was at it. Car is still real sluggish at low RPM’; I get on it and it chug, chug then takes off. I still have a new Disturber Cap, Rotor, Vacuum Advance, and lighter springs. Am I on the right track? Also I’ve printed Lar’s performance sheet and it’s a little intimidating for a guy that has never tuned with a light! Any pointers for a newbie? Going to get into it the next couple of days.
Thanks again! Tom
Thanks again! Tom
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
You need to check your timing. Light springs are good to get advance in earlier but the total advance number itself is critical. Even with a mild engine, you still want 36 total.
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
Hello,
I would take your current settings as a baseline of where you started from. At least if something happens, then you will know where to reset your timing or other adjustements to.
Check Lars paper, there is a small difference between points and HEI units when playing around with the springs. Read through the paper and see if he discussses removing only 1 spring to check for the timing. The reason for removing the springs is to allow the weights to move to the full out position without having to rev the engine so high. If you find this section to confirm what I remember, then you can start looking at the 36 degree settings. Once the timing is set at 36 degrees with the springs out of a points distributor system, and maybe 1 spring out of a HEI system, then you can reinstall the springs, and check the timing at idle. This will not be adjusted, but would be your curb idle setting, which should be in the 12 to 16 degree range. It would be interesting to see where your current settings are now to validate some of your sluggish engine performance readings.
kdf
I would take your current settings as a baseline of where you started from. At least if something happens, then you will know where to reset your timing or other adjustements to.
Check Lars paper, there is a small difference between points and HEI units when playing around with the springs. Read through the paper and see if he discussses removing only 1 spring to check for the timing. The reason for removing the springs is to allow the weights to move to the full out position without having to rev the engine so high. If you find this section to confirm what I remember, then you can start looking at the 36 degree settings. Once the timing is set at 36 degrees with the springs out of a points distributor system, and maybe 1 spring out of a HEI system, then you can reinstall the springs, and check the timing at idle. This will not be adjusted, but would be your curb idle setting, which should be in the 12 to 16 degree range. It would be interesting to see where your current settings are now to validate some of your sluggish engine performance readings.
kdf
