390 pulsing problem- RE-HASH

Phil · Post by **Phil** » September 14, 2007, 9:14 am

Sheered dizzy rollpin?

Pull your dist and put a thin wire through the roll pin holding the gear on.

Perhaps underload it slips but not somuch at idle/cruising speed.

Just a WAG

dotcentral · Post by **dotcentral** » September 14, 2007, 9:28 am

jakdad wrote:It almost sounds like a timing chain gone bad, but I don't remember if you had the occasional backfire through the carb.

Same thing I was thinking. I had a 302 start running a little rough, had a couple backfires. I was planning on rebuilding it anyway so pulled the engine and when I dropped the pan found some little pieces of plastic in the pan. Maybe drain your oil and see if anything else comes out with it? Relatively cheap to check.

blackagatha · Post by **blackagatha** » September 17, 2007, 12:24 am

well.... It's got a Cloyes True roller timing set, that's only 2 years old, and nothing ever comes out of the oil but oil.

Wouldn't a sheared dizz pin mean it would constantly be slipping around, so the timing would be growing quickly and ridiculously retarded?

Pushrods.... I Did Not check them..... that was a dumb move... I ought to check them sometime....
The valves bent (I am assuming) when the engine was reved up to about 5500 (maybe-- my tach is a chunk of shit). and the valves floated.

The engine shop guy explained that when she got wound up, the slack in the valvetrain and a little float allowed the damned hydraulic lifters to pump full of oil, and caused the valves to get hit.