Carb adjustment ideas?
Thread Starter
Burning Brakes
Joined: Jul 2001
Posts: 1,051
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From: Inside every color vette there is a blue one trying to come out!
Carb adjustment ideas?
I just got the vette out of the shop from an engine replacement yesterday. It had an HEI distrib without a tach drive attchment. I had them install a mallory dual points distrib with tach drive so that I could finally see what rpms I was turning. The drive home was good, no problems. This morning, I fired it up and it idled ok but when I drove it, it began to misfire, after getting back to it, had just enough time during lunch to take off the breather and see that it was not a choke problem, the choke was wide open...tried to start it with the breather off and a nice tall flame shot out of the carb. It is a Holly 600 series carb with vacuum secondaries I believe.
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Re: Carb adjustment ideas? (L79vette)
Most likely either the distributor rotated, or the points setting changed.
Another long shot.. and probably not your problem...
I have been finding dimensional incompatibilities between aftermarket intakes & distributors. The diameter of the distributor hole in the intake is often too large, and, the thickness of the intake at the distributor mounting boss is too thin (i.e.- the intake boss is too low)... the distributor bottoms out on the oil pump before the distributor flange comes in contact with the intake boss. The result is that you think you have tightened down the distributor holding clamp securely, when the whole thing is floating. After a few hours of operation, it tends to loosen up and the timing changes. There is a "bushing kit" that is supposed to help with this problem, but I have found it to be useless in most cases because it addresses the wrong issues. Just a heads up on one of my observations.
Another long shot.. and probably not your problem...
I have been finding dimensional incompatibilities between aftermarket intakes & distributors. The diameter of the distributor hole in the intake is often too large, and, the thickness of the intake at the distributor mounting boss is too thin (i.e.- the intake boss is too low)... the distributor bottoms out on the oil pump before the distributor flange comes in contact with the intake boss. The result is that you think you have tightened down the distributor holding clamp securely, when the whole thing is floating. After a few hours of operation, it tends to loosen up and the timing changes. There is a "bushing kit" that is supposed to help with this problem, but I have found it to be useless in most cases because it addresses the wrong issues. Just a heads up on one of my observations.
