How and what to set my timing at on efi/carb swap
Thread Starter
Member
Joined: Dec 2000
Posts: 476
Likes: 0
From: sacramento,ca. usa
Car: 89 iroc,2012 eco 150,roadglide
Engine: zz4
Transmission: t56
How and what to set my timing at on efi/carb swap
I just swapped out efi for a carb.
how and what do i set the timing at?
89 iroc zz4 350 block.
how and what do i set the timing at?
89 iroc zz4 350 block.
Joined: Mar 2000
Posts: 43,187
Likes: 45
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
The best way is to have your distributor "degreed", having the mechanical advance set up to provide the best initial and total advance, then setting the initial after installation to get the proper total.
Short of that, with the vacuum advance disconnected and plugged, set the idle timing to 8-12 degrees. Or, with the vacuum advance disconnected and plugged, set the total mechanical advance (running the engine RPMs up until the mechanical advance isn't advancing anymore) at 36 degrees BTDC. Your initial advance may be too high when setting it that way (often is), but the car will run better if you set total mechanical rather than only initial timing.
Short of that, with the vacuum advance disconnected and plugged, set the idle timing to 8-12 degrees. Or, with the vacuum advance disconnected and plugged, set the total mechanical advance (running the engine RPMs up until the mechanical advance isn't advancing anymore) at 36 degrees BTDC. Your initial advance may be too high when setting it that way (often is), but the car will run better if you set total mechanical rather than only initial timing.
Thread Starter
Member
Joined: Dec 2000
Posts: 476
Likes: 0
From: sacramento,ca. usa
Car: 89 iroc,2012 eco 150,roadglide
Engine: zz4
Transmission: t56
Re: How and what to set my timing at on efi/carb swap
Thanks 57Kid.
I have the timing light I had for the tpi set up, so it does not have dwell? on it..
can't even remember what dwell was. Do I need a different timing light to set timing in "advanced setting"
thanks again!
how about idle speed on carb? how many rpm?
I have the timing light I had for the tpi set up, so it does not have dwell? on it..
can't even remember what dwell was. Do I need a different timing light to set timing in "advanced setting"
thanks again!
how about idle speed on carb? how many rpm?
Re: How and what to set my timing at on efi/carb swap
i did exactly what 57kid said. then it would knock at low speeds under a load. so i got an adjustable vacuum advance and set it up. not ir runs great.
Thread Starter
Member
Joined: Dec 2000
Posts: 476
Likes: 0
From: sacramento,ca. usa
Car: 89 iroc,2012 eco 150,roadglide
Engine: zz4
Transmission: t56
Re: How and what to set my timing at on efi/carb swap
Before the flaming begins lol, I know what dwell is now. won't need one of those meters.
So a light with rpm, advance dial on it sounds best for this then...
So a light with rpm, advance dial on it sounds best for this then...
Joined: Mar 2000
Posts: 43,187
Likes: 45
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
A dial-back timing light usually works. Or, mark your damper for the 36 degree spot. Or, put degree tape on the damper. Or, get a degreed damper.
Just curious, how do you plan on getting this through the CA smog test?
Just curious, how do you plan on getting this through the CA smog test?
Thread
Thread Starter
Forum
Replies
Last Post
1985, 305, 350, 85, car, carb, carburated, carbureted, carburetor, degree, engines, f250, initial, set, timing






