Need help on problem.. Oil pump or cam bearing

[5-oh stang]

This is not on a roller block 302, it is a standard flat tappet motor. The problem is that i pulled a running 302 out of a car, unknown oil pressure at the time due to no guage, pulled the front off the motor and slid in a 351W cam. Got is all back together and run the cam in (breakin) and took the car for a test drive after we put in a fox body mustang. Never looked at the guage when we pulled it out the shop, but on the way back from the 3 mile test drive i noticed very good oil pressure. Some 40-50 psi of oil pressure. pulled back into the garage and put it in park and the oil pressure went to 0. bring the motor back up to 1200 rpms or better and you have 40 pounds.

So whats the problem here. Who's voting for the oil pump and who says its the cam bearings? I really don't want to pull this motor completely apart if i don't have to because it runs just to good. A oil pump would be a easy fix IF thats the problem. What do you think? Thanks in advance.......

 

[5.0Droptop]

I have never heard of cam bearings effecting oil press,

 

[5-oh stang]

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please any input????????????????????????????

 

[Black1987Stang]

I would say oil pump not the bearing...but i think its a faulty gauge or sending unit instead

 

[5-oh stang]

we first thought the sending unit/guage also, but a new out the box mechanical guage reflected the same situation.....

so we got 1 vote for the oil pump

anyone else wanna take a stab at this?

 

[vristang]

Perhaps a bad seal on the pick up tube.

 

[5-oh stang]

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[NKau]

Bad cam bearings will manifest themselves in more of a constant lower oil pressure reading.........i.e. oil pressure stays around 25 psi whether at 1,000 rpm or 5,000 rpm. Pressure just won't build up at higher rpms like it should. This occurs seldomly with just a cam swap (leaving old cam bearings in), but can happen if the cam bearings are somehow galled up on install, or I'd think if the valvesprings on a set of heads were binding with too big a cam, cam bearing wear could occur.
I agree with the guy who mentioned the oil pump pick-up tube however; makes sense that it would seal up and build pressure as more oil moves through it if the seal is bad between the pick-up and pump.

 

[5-oh stang]

First off.... Thanks to all the replies!! I finally got time this evening to pull the oil pan off and take a look. Everything looked good so i pulled the pump and pickup together as a whole unit. The gasket on the oil pump was fine, so i pulled the pick up tube off and that gasket was also fine. I then pulled the oil pump apart and everything looked great. The screen on the oil pump looked clean also, but here is where it get interesting....... i figuted i had nothing to lose so i busted the bottom metal cap off the pickup tube to find the tub running almost all the way to the bottom cap and lots of debris in there! You could not see this stuff just looking at it. It would have fooled the best mechanic just looking at it. Do you think a partially clogged pickup screen would cause this problem?? Thanks again

 

[vristang]

Can you post a pic of where you found the debris? I can't quite follow.

This could be the problem. It makes sense to me.

 

[retro50]

The pump is fine. If you hit the gas and the pressure increases the pump is working. I'd say pull the main caps down and look at the bearings. Bet you'll find them down to the copper.