Seem to have really high oil pressure with my newly built motor.

FM 2.0l stroker. 99 Miata head. Oil sqirters are removed and plugged, VVT style oil pump. 10W-30 Castrol GTX for break in.

Seems like it makes about 60 psi at Idle when warm. 90-100+ up in the rev range and pegs the needle.

Should I be worried about this?

Bob

 

Whoa. This has to be a result of plugging the oil squirters. Lots of people shim their oil pump pressure relief valve to get more pressure so I wouldn't worry about it.

 

what oil pump are you running, i'm curious???

 

Oil pump is a stock Higher flow version from a VVT car 2001-2005. I don't have a VVT head though.

I figured the Bypass should regulate it back near stock.

Bob

 

That is pretty high I have some Honda buddies that had oil pressure that high when they got a little carried away shimming there pumps some of them had no problems others blew oil seals out like crazy. I would say it is a combination of the different oil pump and mostly blocking the oil squirters but it still seems really high for a stock pump. If you don't find a way to get it down some you are gonna have a set of broken oil pump gears on your hands.

 

Did you try putting a manual gauge on the side of the block where the sending unit is just to see if your gauge is off by chance?

 

Same gage as I had before it is defiantly a lot higher pressure than I have had before. Although the last two times I had the motor apart there was definite rod bearing damage which is why I wanted higher flow and have added an Accusump.

Bob

 

I don't think higher oil pressure will break the oil pump. It would more likely make the oil pump more reliable by preventing impact of the parts. My concern is more about seals and the turbo dealing with high pressure.

Bob

 

I have blocked squirters and only have 25 at idle and 65+- at redline. People shim pumps to get a few psi extra, not and extra 35-45psi at idle. Something is off.

 

You could have a possible partial blockage between the block and the head. I assume nothing is making noise? Another thing it may sound weird but throw a new different brand oil filter I have had filters in the past that significantly raise oil pressure but is is really just a blockage. I am not sure where the oil pressure gauge picks up in terms of oil passages but it would be a easy test to check.

 

speaking of oil filters, make sure yours isn't balooning

definitely a combination of removing 4 significant oil outflows while increasing the oil inflow. I would have expected the oil pressure relief valve to be able to compensate for some of it, but the squirters flow a LOT of oil. Tight bearing clearances?

 

The stock 1990 gage on my dash reads pretty close to the gage on my Accusump so I tend to believe it. No real noise but the Goodwin AWR engine mounts are hugely stiffer than Mazda Comp mounts. Lots of buzzy vibration.

Bob

 

Yea blowing a seal out at the oil filter or the stuff I have sandwiched in there such as the stock oil cooler, Mocal thermostat, and Accusump sandwich adapter is a concern.

I had Clevite and King Engine bearings before now I have ACL Race all were stock clearance. I debated on going with the extra clearance ACL's but didn't do it.

Bob

 

Run thinner oil?

 

Yea I thought about that. 0W-20 would probably reduce friction and flow better.

Bob

 

Before you took your old motor apart, did you have any problems related to the rod bearing damage?

 

Re: 0W-20 does the film strength of oil go down with viscosity? That would be bad.

 

No not directly related to rod bearings. I had oil consumption issues past rings and burnt exhaust valve issues. But there were Pits and melted looking spots in the rod big end bearings. I sent the King bearings back to King and they said they were over loaded and that I should be using tri-metal bearings for such high loads. The ACL race are tri-metal. I thought the rod bearing issue could have been because of oil pressure issues under hard breaking hence the added high flow pump and Accusump. Removing the squirters I felt should be helpful for the oil control issues past the rings plus the new style pistons are not really compatible with squirters any way.

Bob

 

Do you know how well the mazda factory bearings hold up under high HP? I am curious because those are what I have in my motor.

 

Did you disassemble and de-burr the new oil pump, or did you put it in as delivered from Mazda?

It sounds like your pressure relief valve may be partially stuck.

I've experienced this in the past - it sucks.

I have a high-flow pump, blocked oil squirters, oil pan baffle, and get 25-30 psi at hot idle. ~75-80psi at redline (8500 RPMs).

FWIW, I have had problems with the pressure relief valve on my street car and my track car. For this most recent build, I sealed the stock oil pressure relief valve and am using an external in-line adjustable pressure regulator. Works very well.