Remote Oil filter & Cooler Plumbing

TomR · 05-12-2002, 08:48 PM

I seem to have high oil pressure on my GenVI 502. It is about 60lbs at idle warm and goes over 80lbs when motor runs over 3000 rpm. The only thing that changed from last year was a cam swap to a CompCam roller cam & lifters replacing the stock roller lifters that were run with a GM 502/502 cam last year.
When I first installed this motor last year I utilized the remote filter & cooler that was on the GenIV 454 replacing the remote filter bypass thet Merc used, to a universal oil filter bypass.
The oil pressure last year was a little high, but not like this.
I did notice that the oil lines going from the motor to the filter & cooler seemed to be crossed so I changed them.
I ran the lines so as the ports were duplicating where they would flo into the filter if the filter were directly on the block.
Have I run them incorrectly???
I was thinking of utilizing the two oil cooler ports that on are GenV / VI block in front of the oil filter pad for the cooler??
I am thinking of doing away with the remote filter, I have enough room to access the filter for filter changes.
Any thoughts on this?

CheckmateF1 · 05-12-2002, 10:22 PM

Tom, the two cooler ports on your block in front of the filter pad are 3/8" pipe thread and they are too small for marine oil cooler lines. You should use all 1/2" (or -10AN) hose and fittings for the oil system.

Looking at the filter pad on the block(if you can see it) the center port, where the filter would screw on, is the return port. i.e. oil is going back into the motor. The outer perimeter is oil coming out of the block. The same flow applies to any remote oil filter housings you may have.

Eddie Marine has a nice peice that will screw directly to the filter pad on the block. It has two 1/2" ports for the oil cooler and also allows you to screw the filter onto it. If you have the room then it would work great.

hope this helps, Eric

MACDAD260 · 05-12-2002, 10:41 PM

It sounds like you are OK with the cooler and filter plumbing. I agree that you should not use the cooler ports in the block. They will not flow enough oil for marine use. Regardless of how your filter and cooler are plumbed, I don't think it will affect oil pressure. Oil pressure is usually read on the return side after the filter/cooler. Even if the filter/cooler was plugged and not flowing any oil at all you will still have pressure and flow due to the bypass valve in the filter pad on the Gen V/VI blocks. Maybe your gauge is off. Try checking the oil pressure with a mechanical gauge. If it is still high then maybe the pressure regulator valve in the oil pump is not working. Good luck.

TomR · 05-12-2002, 10:58 PM

Thanks for the input.
I'm certain I have it plumbed correctly, after posting early this eve I found a diagram in the Merc parts at BAM. I have the hoses correct. I don't think I had them right last year though!!
Motor ran good and changed oil often, no noises, maybe it's just the new cam and lifters are tight. I have only ran it in the yard since the changes. I will take it for a short blast on the water to really check things out this week.
Installing a mechanicle gauge at the filter housing should give me an accurate reading. The boat, gauge & sender are over 14 years old.
Maybe having the hoses wrong last year clogged up the bypass and with any luck a short run with evertything correct will solve the problem.
The motor only has about 40 hrs on it total .