mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
- Messages
- 5,249
I know this has been beat to death but make sure the rear cam bearing is installed correctly. Take the rear cam plug out and make sure the bearing is covering the oil feed hole.
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SignUp Now!Is this a factory or aftermarket timing cover? If aftermarket, check for cracks. If it is factory, check for cracks. So, check the timing cover for cracks.
I only radius oil passages in the timing cover, but not enlarge them. The stock timing cover will feed enough oil for a 600hp engine. I am just jealous about making things better, so I radius all the passages and then spend copious amounts of time setting the oil pump clearances. It sounds like there is a timing cover issue to me, though. You might just want to try another one to rule that out.
I don't think that a .020" bigger cam bearing would restrict oil flow to that main bearing significantly. It is only .010" farther into the oil gallery that is already HUGE.
edit: Also check the oil pressure relief valve for smooth operation. Also check the oilfilter adaptor for cracks, too.
Once upon a time I checked for internal oil leaks with a garden hose. Engine on the stand, front cover off, garden hose hooked up to the oil pressure sender port. I was taking the thing to the machine shop anyway, so I didn't feel bad about it. I did have to figure out ways to cover up a few other holes before I did this. In the end it was quite informative - I found my major leakage was between the #1 cam journal and bearing. The wear didn't look that bad to my eye, but the water flowing out from there didn't lie. You could do something similar. If there is a crack or something somewhere, it would show up with this kind of test. Gotta do the suction passage separately.
Another guy here in Houston did something similar, except he had his machinist set up the test and use a light oil instead of water. They found a major leak between the block and the #1 cam bearing. The hole in the block was apparently out of round, or distorted in some way. He lost 3 rebuilds because of it. They had to hone that hole out and use an oversized bearing, but once they did that his engine finally lasted and kept good oil pressure.
I think a similar test might help you find your problem. Maybe use a light oil, and pressure it into the engine with an air compressor, so you don't foul everything up and require a complete disassembly and cleaning. Since you have good pressure cold but poor hot, I'm guessing that it is a small leak somewhere that doesn't become bad until the oil thins out. Once the oil gets thin, then enough escapes through the leak to drop the pressure.
John
Well, if you know the issue involved the cam bearings and alinement, why didn't you get that fixed? I am assuming the rest of the build was fine. Did you just get frustrated with the whole think and not want to look at it anymore?
X2 I had a guy cut the side of my rods and it just killed any chance for correct oil pressure...What was the side clearance of the rods?