Thread: Gen V oil pressure issues

Tweet

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?