low oil pressure and a good story
03-05-2006, 03:46 PM
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low oil pressure and a good story Well, one of my good friends with a 99 Z28 recently did a heads and cam swap. Patriot LS6 style heads and a TR 220 cam. He also had a double roller timing chain installed, and new pushrods. The shop that did the install is Bottle Fed Racing out of Redlands CA. I did the tuning for him. He was driving it back the first time (lol, first) and about 5 miles away he got this horrible banging noise. It sounded like a rocker or a pushrod trying to shoot out of the valve cover. It was late at night, so I had to come and pick him up and we had his car towed back to the shop. Later on they discovered 1 of rockers was loose on the driver side. So they re torqued everything and sent us on our way.
It seems to run fine now but... the oil pressure is horrible (it was ever since they touched the car)! It's 20 lbs at idle when it's COLD! It will fluctuate too, it's not very steady. I don't think it goes any higher than 40. My friend said the first time they started it, it took it about 20 seconds to build pressure. My SS is about 60lbs at idle cold and my vette is around 50lbs. Here's the good part. The shop said they drained the oil pump and that it takes some time to work out all the AIR?! That doesn't sound right to me. Is this a sign of a bad O ring install? I don't want my friend to toast his
engine.
It seems to run fine now but... the oil pressure is horrible (it was ever since they touched the car)! It's 20 lbs at idle when it's COLD! It will fluctuate too, it's not very steady. I don't think it goes any higher than 40. My friend said the first time they started it, it took it about 20 seconds to build pressure. My SS is about 60lbs at idle cold and my vette is around 50lbs. Here's the good part. The shop said they drained the oil pump and that it takes some time to work out all the AIR?! That doesn't sound right to me. Is this a sign of a bad O ring install? I don't want my friend to toast his
engine.
03-05-2006, 03:51 PM
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Sounds like one of two problems to me if I were to take an educated guess. Eithor the O ring is pinched or the cam journals are small and letting oil pressure bleed off. I would think it is more the O ring being Thunder has been doing cams for awhile and seem to have a pretty good track record of keeping things in spec. I'd ensure a new O ring was installed. If it was then I would probiably pull the front cover off the motor and put another new O ring in and also while you are there pull the cam and check to see what the journal diameters are, even though that is doubtful. Might as well you are right there. Engine gets oil pressure from the clearances on the main and cam bearings in the engine. Too much clearance will cause a pressure problem particularly when warm.
03-05-2006, 04:05 PM
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I also say it's the oil pump O-ring that is pinched, almost positive it is. Had this same problem with a truck I did a cam install for (new timing chain) and the symptoms are very similar.
03-05-2006, 08:19 PM
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Cool that's what I was thinking, but it's always nice to ask. I'll have him get a new ported pump while he's at it. For some reason he didn't get one. I wouldn't mind doing it for him... but I hate working on friends' cars... if the tiniest thing goes wrong you'll never get rid of 'em. Ask me how I know? 
