Thread: Gen V oil pressure issues

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Originally Posted by gravensg

The bearings were inspected and plasta-gauged at the time... I do not recall a # but I called the builder and the clearances were accurate with his records. He stamps the block and can look up the build sheet. The builder started the motor on a test stand and broke it in; only way he would stand behind his work. I moved, and the 90 days has long expired since the original light off.

Started at the 5W-30 and am now at the 10W-30. I did run 20W50 in it once just to see and do not remember it having a “WOW” type effect when hot. I guess I need to pull the motor again. Several K in the machine work and parts, and I am thinking I would like to keep the parts inside the block, or the bearings in place.

I am not happy with 45 when the motor is designed to pull 6K RPM. I believe the rule of thumb is 10 psi/1k in RPMs’.

that s.. bull $hit i have built many bbc you want more then 45 when at WOT you have still not said were your bearings are at ? spec is 001.5 to 003.5 like i said if loose it going to be low try a strait 40w or 50 w your still at 45 with a HV oil pump? what cam do you have ? the wrong roller lifters will bleed off psi if its still looks good then it loose bottom .i never check much with plastigage i set my mic i read the crank size off and set the bore gage off the mic size and read the housing bore with bearing in thats the only way to know for sure

With the crank in place... just changing the pump the plasta-gauge was the best option, I agree that bore gauge is the better option if you have it torn down.

If I remember correctly clearance was ~.002. How is this; I KNOW it was not out on the open end of the tolerance.

The Cam and lifters are GM parts 0.527" / 0.544" lfit, 224 / 234 degrees duration @ 0.050" lift 502/502 cam shaft.

Know anything about the bypass ports under/ by the oil filter?

Originally Posted by gravensg

Know anything about the bypass ports under/ by the oil filter?

yes i do you can take it out or leave it in if working thats not it .i just built a 489 v engine and it has 45+ idle and 65 off idle it engine makes this with the bypass in and a Mv77hv oil pump. rods at 002.6 and mains .002.8 .if your telling me that its not loose and all things i listed are fine then why is it low ? try a new oil gauge? your old gauge is a mechanical?

Tried oil pressure gauge had a mechanical autometer, put an electronic autometer on. That is why I think it is bleeding internally. I cut open a filter and no sign of termoil... It is pissing me off. I have a 454 w/ 150K+ miles on it and pulling a trailer,hotter then hell out the oil never drops below 30 psi at idle.

Originally Posted by gravensg

Tried oil pressure gauge had a mechanical autometer, put an electronic autometer on. That is why I think it is bleeding internally. I cut open a filter and no sign of termoil... It is pissing me off. I have a 454 w/ 150K+ miles on it and pulling a trailer,hotter then hell out the oil never drops below 30 psi at idle.

well were it would or could bleed off is loose rods and main s loose oil pump loose cam . other things like plugs not in block . all things i listed .but the mains and rods i would bet is what going on with this .or your getting the oil so hot its like water and pissing past the mains and rods loose mains and rods will not make it better .i told you i did not hold the 10psi for every 1000 rpms for much .i built many engines .but think about it .if you held your rule 10 psi for 1000 rpms you only need 10 psi for 1000 rpms thats past idle on some engines

engine is not that hot and it has an oil cooler on it. 220 is about as hot as it gets and that is at a stop light after a long run. I guess I will pull the POS out and start digging. I believe it is "Smokey" Henry Yunick's gives the general rule of thumb of 10 psi/1000. I have had some pretty tied engines that build more pressure than this thing, copper on the babbit showing...

If I find something I will take a picture and send it across.

I looked in my 97s' service manual and the main bearing clearance varies with the main cap location. I hope the crank is not F' bombed!