Thread: Gen V oil pressure issues

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Ihave a Gen V 454 +.030 freshly professionally built. It has crappy oil pressure when hot. ~10 psi at idle and 35/40 running down the road. I pulled the motor and replaced the pump w/ a Milodon 18760 pump. I checked the bearings and everyone looked happy using plasta-gauge.

I plugged the cooler lines that did not help. Somewhere it is bleeding internally. Does anyone have any ideals on what might be missing inside the motor? Of course the builder is saying it is fine… It is not his money of course it fine.

is one of the 3 valley plugs out ? there 1/8 plug and come off the cam bearings if one is off your going to drop psi here a photo of the plugs . front plugs under the timing cover could be out you will have very low oil but no upper oil to rockers and if valley plugs is out main bearing would not look to hot ? 10psi hot is ok and45 long as oil psi builds and not drops .the rear main caps have a poor machine finsh .on the block it is choppy they are cut for a O ring to seal cap better to the poor finsh as oil pass thru the main cap cuts down on oil leaking .i do not know if any of this will help you did not say how big you oil clearance is if big it is going to be low . you did not say were your at with the new pump for PSI but on big size oil clearance past 003.+ loose rods side clearance .cam under size on journals ?your going to be low on oil PSI with new pump and you 25 idle and 65 that is just big clearance and that will not hurt any thing .what oil Wt are you running ? had a customer had some thing going on like on a short block he built. this but was abit lower psi and would not build much psi he had studs on the mains and all six point nuts held the pump off the base of the main cap just a wee bit . letting oil to pass a 12 point nut fixed it

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’.

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!

Originally Posted by gravensg

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!

yep i know who said it as for cap location the rear main comes in a abit bigger they are all the same size on main housing bores.i built many hi hp bbc 450and past 900 hp how i fit the bearings will change abit .i go by the book on crank and housing bore size on stock or on race stuff and thats the small number on housing bore size. if crank needs to be ground we grind it to the size of real bore size with real size bearings TQ in and cut the crank for the size we want or fit the bearings to the size you want to run its not hard to be to big if you do 1/2 ass machine work there is allmost 001 on main housing bore same with rods housing bore size is 0005 by the book spec s now how much will you live by from size to size when you rebuilding a housing bore ? mains or rods? i keep less then 0002 with tapper and no more down from were i want it for size .if your work by the small and big numbers in the book for a housing bore .now add a crank low end of spec with a under size bearing i have seen with my own eyes many time them as much as 0005 from mich .to king to ACl. all this adds up.as a bbc engine builder and a owner of a engine machine shop i do know what works for me and were i will machine housing bores and grind the crank to so i know were i will be about were i want the bottom end to be at

I know the guy knows what he, builder, is doing. He builds circle track motors, engines that have been out on the salt flats, and 1/4 mile stuff and wins or goes damn fast trying.

Just not sure, and disappointed that I tried to spend the cash and just have a tough BB.

do you have bearing preferance? king, Clevite, Child & Albert...

Originally Posted by gravensg

I know the guy knows what he, builder, is doing. He builds circle track motors, engines that have been out on the salt flats, and 1/4 mile stuff and wins or goes damn fast trying.

Just not sure, and disappointed that I tried to spend the cash and just have a tough BB.

do you have bearing preferance? king, Clevite, Child & Albert...

for what stock or race i use .kings.acl. clevite. speedpro s and feds ,some for stockers to mild builds and other hi hp street to race