WTF? Engine is running weird
06-16-2009, 08:17 PM
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WTF? Engine is running weird So I head to the drag strip to make a pass with the new cam/heads set up and notices it's idling a little different. Make a few passes and it dies at the end of the track. I get it started and drive it home, but I noticed the oil pressure was hanging kinda low at 25psi cruising. It runs and makes good power still, but at idle, it sounds more "tame" like it's not as deep and healthy as it was. I'm thinking bent valve or pushrod maybe, but took the valvetrain out and pushrods are straight. I threaded a hose into the sparkplug hole and ran compressed air into the cyilinder to check for leaks. Intake/exhaust ports have no air so valve's must be seating and sealing. I do have air leaking past the piston I guess cause I hear the air leaking and it's coming out the pushrod holes of both heads. I'm only putting 80psi in the cylinder and motor only has 900 miles on it. Any ideas whats going on?
06-16-2009, 09:10 PM
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Tune seems pretty decent. It had a lot better street driveability before the track and runs good, but it's low on power. I was expectiing 440rwhp or so and only got 406 out of it. A buddy of mine says the chomoly rings take about 5k miles before they really seal up and I'm prbably loosing power there. Same thing behind the air leaking by them. It's just got this nasty sound that sounded like it was right under the rocker panel and the exhaust sounds different. Hard to describe but "hollow" instead of deep and throaty like it was. But everything looks good. Valves and pushrods arn't bent. I'm a little confused.
06-22-2009, 05:29 PM
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I could be wrong, but I think what waterbug meant is " How's your tune now?"
did something happen at the track to make the computer start pulling a bunch of timing?
did something happen at the track to make the computer start pulling a bunch of timing?
06-30-2009, 04:52 AM
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hmmm...definitely seems like this might be an oil pump problem. 25psi is getting pretty low. when you put the motor all back together, did you center the oil pump on the crank? if i remember right, there's almost .100" of movement from side to side, which can cause premature oil pump failure if it's not close enough to being dead centered. any possible way you could have dropped some gasket material in the pan when you pulled the timing cover? could have something stuck to the end of the pump filter partially starving the pump of oil, hence causing the low oil pressure. trying not to be the bearer of bad news, but that's what it sounds like to me.