Oil pressure high!
 

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 :giggle:

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.

I just stuck the pump in as it arrived. Never had issues with a pressure relief valve befor.

Bob

I was under the impression that improved crankcase evacuation was the end-all solution to oil control at the rings. I could have swore you spent a good deal of time on this? It doesn't matter how much oil your squirters are squirting, if the pressure in the combustion chamber is greater than the pressure in the crankcase (which it should be at least 75% of the time), it makes it very difficult for oil to get into the combustion chamber.

I'm no fluids engineer though, so my hypotheses (plural for hypothesis?) are subject to being wrong.

I was not aware of the higher volume of the VVT pump, but that does make sense now that I hear it. How much flow boost is there? With oil squirters blocked off, and the extra flow, perhaps bearing clearance is a bit tight, maybe the relief valve cannot dump enough volume, and the pressure rises.

A thought comes to mind for me, how hard is it for you to remove everything between the block and the filter, run it like that to see if there is a restriction there. That should only make a difference if you are pulling pressure reading at the adapter, as I believe the boss in the block comes after the filter.

I would also consider checking pressure at one of the head oil plugs to see if it is high/low there.

Hydro or solid lifter in this engine?

My guess would have to be there is a problem with the relief valve tho.

The crankcase venting issue is not necessarily related to oil getting past the rings. You can have a finely vented crankcase and your rings can not seal well.

Hey bbundy, fae just called your engine a "piece of shit"!!! :giggle:

LOL

I meant "one can have a well vented crankcase and the rings still might not seal well". ;)

There are allot more issues with oil control at the rings than crank case evacuation.

1) forged pistons with more clearance than stock

2) Extremely short height pistons with the stroker so they can rock in the bore more.

3) The fact that all aftermarket pistons I have seen have gas vents in the oil control groove vented to the underside of the piston where pressurized oil sparay from the oil squirters is and Mazda factory pistons do not.

I will say I’m not leaving an oil smoke trail anymore when I romp on it.

Bob

It seems to have cured itself. now it idles at ~30-32 and ~80- 90 under load. I think the relief valve was sticking.

Somthing has let go in the driveline. sounds like metalic popcorn in the transmission. but I just put in a junk yard 3.636 ring and pinion with an OS-giken so I will have to figure it out tonight what is going on.

Bob

I have an Accusump with a gage on it mounted under the car back by the fuel filter It is connected into a sandwich plate under the oil filter. It reads pretty much the same pressure as the stock pressure gage. Both are after the filter.

It is a ported 99 head with oversize valves. Stock solid lifters and cams. I think the flow increase with the VVT pump is pretty small actually. I doubt it is as much as a Boundary engenering pump.

Pretty cool to see oil pressure come up before I hit the starter button.

Bob

Good to know it cured itself!

Bob before your accusump did you ever hear a clatter when you started up?

Not really. And unsprung 4 puck clutch disk clatters a little as its kiking off though.

Bob

Good news on the oil pressure situation. I had a temperature-related sticky relief valve once. Oil pressure was sky-high until oil came up to temp, and at which point, pressures would run as normal. The slight change in temperature was just enough to expand/contract the housing. Eventually though, the piston got stuck. Hopefully that won't be the case for you.

Good luck with the drivetrain, and let us know how it goes with the crankcase evacuation kit and light weight alternator in your other posts!

Interesting my rebuild job on the diff seems fine I've done like 5 of them and haven’t had a problem before but I was worried. Can’t really identify issues with the transmission. There is about 10 degrees of slop in one of the inner CV joints, don't think that is right.

Anybody else blow up CV joints? It’s got like a driveline vibration and does a lot of clicking and popping. even going straight loaded or unloaded. Lightly loaded at 3500 rpm it vibrates the whole car.

Bob

sounds like a cv probly the tranny would make alot more gruesome sounds pretty quickly.

How warm is warm? Mine does this exact thing when it's cold, are you sure you didn't just let it warm up more when you thought it cured itself? Much above idle when mine's cold and it's pegging the pressure gauge.

I drove it for a loop around the Island about 15 miles and pulled it in the garage and it still had 80 psi idling.

Bob

Yes. That is exactly what my blown CV sounded & acted like. Not common, but it happened on my stock engine 125-130hp track car.

Weird it didn’t have these severe syptoms before I took it apart and installed the OS-Giken and the rebuilt engine. I wonder if I swapped sides with the axles and that is what pissed it off when I put it back together.

I just took the CV apart, huge divots in the inner and outer races where the balls come in contact, lots of slop in one spot. Grease looks fine, looks more like serious overloading than slow wear really. I wonder if this is going to be a weak link for a car making over 300 ft-lbs of torque.

God it feels cool to romp on it when you’re going 60 mph and have the rear tires just start spinning though. My junk old Toyo T1-S tires are entertaining for this.

Bob