CHEV HI PERFORMANCE ENGINE WITH A MIND OF! ITS OWN

What can cause an engine to run ( and it runs very good: on the engine stand at 800 RPM's it has 20 Lbs. of vacuum, an air/fuel mixture of 12.5, and accelerates very quickly and cleanly ) with 33 degrees of advance at the damper with the distributor weights and
vacuum providing none of the advance!!! (they have been disconnected to isolate the problem.)

This is a 350 ci chev engine with a 350 H.P. 327 c.i. cam, with 202" heads and Hooker 1 5/8" headers. The marks on the timing gears have been re-checked to be sure they are are set correctly , the timing gears and chain have been changed, the timing light has been checked and is working properly, the camshaft has been checked ( and replaced ), and different carbs, intake, and distributors have been tried with the result being the engine requires the same 33 degrees of advance to run right. The timing mark has been verified to be correct by checking it against TDC. The engine will run with 16 degrees of initial advance, but is real doggie. When the timing is advanced from 16 degrees it runs better and better until it reaches the "sweet spot" at 33 degerees BTDC. If it is advance any further it starts to stumble and is hard to start. The point is the 33 degrees is exactly what the engine requires to run right. What could be causing this?


------------------
B CORNELIUS

 

I've been there bro...
Your not running with a 33 degree advance, it's the timing mark on the damper that's different. Believe me I've been there. When you hit the timing lights the mark seems to be at the passengers side away from your tab right ?? Well I used my '89 damper on an older block 350 and found the same thing, until I changed to another one, check application...

(I've also heard that the piece of the damper that has the marks on it could actually spin from it's original place if abused. The damper is supposed to be a 2-piece unit.)

[This message has been edited by Baz89RS (edited October 26, 2000).]

 

Are you absolutely sure your hooking the timeing light to no. 1 cylinder? Left front I think. I've made that mistake and scatched my head a bit.
If the balancer ring had spun it would not line up at top dead center.

Bear Tracks