Oil pressure question

brianflhrci

A few years back I had one of my Mercruiser 5.0's replaced with a Jasper based upon the Mechanics recommendation about a better warranty.  When I took the boat back he mentioned that Jaspers tend to run higher oil pressure and that was why the gauge was reading close to 80psi when I took the first test drive.  Fast forward a few years the pressure reads at or above 80 when I'm at about 3/4 throttle and I don't want to push it further.  Is the mechanic full of it or do I need to get a new sending unit/gauge so it doesn't bother me?

Thanks,
Brian

GMSLITHO

Try putting a gauge on the block 

Handymans342

Nothing wrong with 80

brianflhrci

I'll try the gauge at the block, do you think it needs to be underway or just rev in the slip?  I worry since I'm getting two beeps every minute if I run it and the gauge reaches 80, if I keep it at 75 no beeps at all.

aero3113

My 5.7 is a Jasper also and reads 80 psi at cruise, when I'm at idle it reads about 40-50 psi.

brianflhrci

It's good to know that's normal for jaspers.

212rowboat

There is danger with a high pressure or volume pump if the block isnt provisioned for it, primarily the dizzy gear on the camshaft becoming starved.  Many will drill a hole in the valley atop the dizzy to provide more oil draining over that gear on its way back to the sump.  Other concerns are of keeping too much oil in circulation and out of the pan, causing it to retain heat more than it would if it was allowed to rest, and the pump actually running dry due to loss of available oil.  

It does, however, keep the valve train oiled better, and the cam, except for the back of it on that dizzy drive. 

A hole for draining tapped above that gear and a larger sump (more volume of oil) solves this riddle. 

Michael T

80 psi is getting a bit high for my liking - unless (as@212rowboat says) the engine has been prepped on its build for that pressure. 30 at idle 50 at cruise no sweat ......80 IMO a bit high.

pistole

What's the point of having oil pressure like that?

Michael T

.......blowing seals to make work for techs?