Ok, so my new motor has an oil pressure problem.

Even after the oil has warmed up, the pressure is still at almost 60 psi at idle. That is not good.

The motor has about 500 miles on it, the oil pump is a Melling 'high volume' unit, and the motor has two (2) breathers on it.

I don't really know what to do about this problem/ how to fix it.

To the best of my knowledge you want about 30psi at idle and a gradual increase as rpm increases. I also know that the high volume oil pump should not change the psi of the oil.

Any sugesstions?

 

My engine has the same oil pump as you (me55, I think), and also have pretty high oil pressure. 2 things - if your bearing clearances are tight, then the pressure will be higher. For example, my rod bearing have something like .0015 clearance (measured with plastigage, so take it with a grain of salt). Second, those oil pumps come with a spring that changes the way it works. My machinist decided it was best to keep it the way it came from the manufacturer.

Anyway, my oil pressure runs around 60psi at idle when cold, and drops to around 40 or maybe 50 after warm up. I don't sweat it too much. One thing you could consider, maybe, is changing your oil to synthetic and run the 5w-30 stuff. I may do the same thing. With those tight clearances, it'll drop the pressure some, but that oil is really good so I wouldn't worry about it.

lastly, you could give the motor some more breakin time, I suppose, to see if things change.

 

i don't think you have a problem. are you using a mechanical gauge?

 

I am using the stock sending unit and gauge.

Are you sure I don't have a prob? I hear that too much oil causes the oil to be pushed out of the engine which can cause leaks.

 

with the stock gauge you don't have a good idea of what's really going on inside your engine

 

Can you elaborate?

 

Factory gauges are notoriousy innacurate, at best. Aftermarket electrical are better, more reliable. Mechanical gauges are the most reliable.

 

A high volume pump CAN increase low RPM pressure if the engine clearances are tight enough not to let the oil bleed off faster that is being pumped, it can be as high as the pressure relief is set at.

 

Well, is this going to be a problem?

Do you guys think that it'll get better as the engine breaks in and the clearances smooth a bit?

 

There is nothing wrong with 60 psi. My car has 130,000 on totally original engine and it runs 60 psi at anything over 30mpy, and 30-40psi at idle. Oil pressure is a GOOD thing.

 

I would check the actual pressure with a mechanical gauge, if it's still high you could try switching to a 0-30w oil. Why did you run a high volume pump in the first place? A stock pump is plenty for almost any engine unless it's set up with loose clearance. The high pressure may not hurt anything but it's going to cost a little HP.

 

I run the same pump, the MellingHV55, I get about 35PSI idle fully warmed up, as soon as my engine is at 1000RPM my oil gauge is pegged to 60psi.

 

I ran this pump because the engine builder TOLD me to.

I guess it is no biggie. Thanks for the help guys.

 

On both the 305 I had along with the 400, which has slightly looser clearances, when cold I run 65 PSI, when warm 45-50 (At idle). Forget the stock gauge. Mine only goes up to 60, so it stayed buried half the time.

Gave me an excuse to get a A pillar pod!