Timing my 351CJ
Thread Starter
Joined: Jun 2014
Posts: 8
From: Montana
Timing my 351CJ
Im having trouble getting this done. Can somebody walk me through this. Im running a 1972 351 Cobra Jet 4V with a C6 edlebrock performer intake and 650 Carb and GM style HEI ignition. I also live a mile above sea level, dunno if that affects it at all. Ive tried to get it set between 12 and 16 degrees but without much success. Just need a walkthorugh on timing this engine. Any helps appreciated.
6th Gear Member
Joined: Mar 2010
Posts: 5,059
From: Wisconsin
Pull the vacuum advance hose off dizzy, loosen clamp, turn dizzy till timing is at 12' for starters. Tighten clamp, reattach vacuum advance hose.
Get the motor up to temp and make a couple WOT runs lugging the motor in the lower rpm range till top end. Listen for detenation/pinging. Advance timing till you hear that then back timing off 2'.
Done
EDIT: sorry, just reread you have the GM HEI dizzy, I think those are still vacuum advance but someone correct me if I'm wrong. Also, make sure your vacuum hose is coming off a timed port. Meaning you won't have vacuum on that hose at idle. With a constant vacuum, car will start hard when hot because vacuum will be advancing the timing while cranking.
Get the motor up to temp and make a couple WOT runs lugging the motor in the lower rpm range till top end. Listen for detenation/pinging. Advance timing till you hear that then back timing off 2'.
Done
EDIT: sorry, just reread you have the GM HEI dizzy, I think those are still vacuum advance but someone correct me if I'm wrong. Also, make sure your vacuum hose is coming off a timed port. Meaning you won't have vacuum on that hose at idle. With a constant vacuum, car will start hard when hot because vacuum will be advancing the timing while cranking.
Last edited by 88 orangepeel notch; Jul 29, 2014 at 07:53 AM.
Thread Starter
Joined: Jun 2014
Posts: 8
From: Montana
Pull the vacuum advance hose off dizzy, loosen clamp, turn dizzy till timing is at 12' for starters. Tighten clamp, reattach vacuum advance hose.
Get the motor up to temp and make a couple WOT runs lugging the motor in the lower rpm range till top end. Listen for detenation/pinging. Advance timing till you hear that then back timing off 2'.
Done
EDIT: sorry, just reread you have the GM HEI dizzy, I think those are still vacuum advance but someone correct me if I'm wrong. Also, make sure your vacuum hose is coming off a timed port. Meaning you won't have vacuum on that hose at idle. With a constant vacuum, car will start hard when hot because vacuum will be advancing the timing while cranking.
Get the motor up to temp and make a couple WOT runs lugging the motor in the lower rpm range till top end. Listen for detenation/pinging. Advance timing till you hear that then back timing off 2'.
Done
EDIT: sorry, just reread you have the GM HEI dizzy, I think those are still vacuum advance but someone correct me if I'm wrong. Also, make sure your vacuum hose is coming off a timed port. Meaning you won't have vacuum on that hose at idle. With a constant vacuum, car will start hard when hot because vacuum will be advancing the timing while cranking.
Im kicking myself for not knowing this but i guess it come with the territory of old engines. Where do i find a timed port? My dizzy has vacuum at idle so i'd like to remedy this problem. Thanks Orangepeel!
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