Timing Question on a 79
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Timing Question on a 79
Installed a new GM 290hp crate motor a few weeks ago and I'm still trying to work the bugs out. The instructions that came with the motor say to start out with 10 deg btdc and work from there. My problem is this. I disconnected the vacuum advance and bring it to 10 btdc. However after I reconnect the vacuum advance the idle goes up and the timing changes to maybe 14 btdc or more. If I bring the idle back down the timing is off again. Am I doing something wrong? Can I time it with the vacuum advance connected? Also how much advance at idle is acceptable? The most I've ever heard of was 12 btdc, that was on an old Trans Am I had. I dont want to overtime or crank in too much advance and cause myself some other problems. Thats why I needed a new motor in the first place. I cranked in too much advance and wound up bending a wrist pin. Didnt get any pinging either, just a lot of clanking and banging.
I'm running a new gm crate eng, MSD 6a, msd 8.5mm wires, delco plugs, edelbrock performer carb and intake.
Thx, ESU in NY
I'm running a new gm crate eng, MSD 6a, msd 8.5mm wires, delco plugs, edelbrock performer carb and intake.
Thx, ESU in NY
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
Download a copy of Lars timing paper from www.corvettefaq.com
And read this thread: http://forums.corvetteforum.com/show....php?t=1045725
And read this thread: http://forums.corvetteforum.com/show....php?t=1045725
