Yeah, yeah, I know. It's not likely the oil pump but humor me.

The red aka turbo car is showing low oil pressure. It has a front mounted oil cooler and some sort of big bore engine. Oil level is full cold and when hot.

When cold my oil pressure is good, when hot it isn't.

I'm under 10 PSI per 1000 RPM hot.

I don't have a history on the engine.

I am running 20w50, Mahle filter.

I have not put a mechanical gauge on it but it is already running a retrofitted VDO oil pressure gauge.

Goal is to get another summer out of driving it if I can.

I supposed it wouldn't hurt to try a mechanical gauge and heavier weight oil, but is there a chance it is the oil pump rather than bearings?

no, its the bearings. blew up my motor with the same symptoms.

I agree would be the bearings, probably rod bearings first, but cannot hurt to make sure that the engine is running at 190-205 F with straight 40 Weight oil

Darn it - enough with the good information! Tell me I need blinker fluid or something simple...

pull the sump screen and run your finger around in the case , hope you done get a sliver

If it is the bearings, which probably is the case, that’s a full engine rebuild at that point, correct?

Afraid so. Gotta pull it all apart to replace bearings.

Thanks - it is what it is. Might be time to dust off that 3.2l engine. The remaining bits that I need to buy to do that conversion will probably be close to the cost I’m having this thing rebuilt.

Test, don't guess.

Test the pressure with a gauge you know to be accurate.
Then if it does really have low oil pressure look at possible causes before you condemn the engine outright.

A stuck oil pressure relief valve that does not seat well could create the symptoms you are seeing. Chris at Tangerine Racing makes a replacement oil pressure relief valve that addresses the poor seating problem these cases and relief valves have.

Jim

Well that seems like good advice - let me get a gauge on it.

How do you confirm if the oil pressyre relief valve is an issue?

It is a bit subjective but if the pressure is low I would pull the pressure reilif valve and inspect ir and the bore and seating surface in the case. There is a machines step in the bore in the case that is not always in good shape. You may be able clean the bore of the oil and and see wear marks where the valve seats and evaluate if it is seating well or not. You may need ot use some bluing or dye to see the seating surfaces and evaluate the seal. Also the bore waers and the relief valve can stick in the bore so it does not move as intended.

Jim

[quote name='jcd914' date='Apr 19 2019, 12:24 PM' post='2706582']
[quote name='Tdskip' post='2706574' date='Apr 18 2019, 05:11 PM']
[quote name='jcd914' post='2706569' date='Apr 18 2019, 07:06 PM']
Test, don't guess.

Test the pressure with a gauge you know to be accurate.
Then if it does really have low oil pressure look at possible causes before you condemn the engine outright.

A stuck oil pressure relief valve that does not seat well could create the symptoms you are seeing. Chris at Tangerine Racing makes a replacement oil pressure relief valve that addresses the poor seating problem these cases and relief valves have.

Jim
[/quote]


Well that seems like good advice - let me get a gauge on it.

How do you confirm if the oil pressyre relief valve is an issue?
[/quote

No point in condemning this motor to quickly.OP needs to fit a gauge straight off the engine as mentioned.
The following should be looked @ ;
Is the engine clean,
is the timing spot on,
is the motor in tune ? values done recently,
is the thermostat for the cooler working correctly,
is the cooling system working as it should,
The above listed have a lot to with oil temp with ends up being oil pressure !!!.

Thanks gentlemen, I’ll slow down and do a better check. My hunch is that it is toast but maybe not!

So I picked up a replacement oil pressure relief spring, from what I’ve learned from you all it’s probably not a bad thing to have on hand anyway.

I believe the cover for this is located next to the oil filter on the bottom of the engine, correct?

Will this cover and screw readily with just a long screwdriver or do I need to remove the oil filter to get better access?

Not my car but I believe this is what the cover looks like, correct?

Thanks!
Click to view attachment

yes and the other one through 74 is in the relief on the left drivers side of the block

Thanks George.

To install a mechanical oil gauge to test the oil pressure I simply remove the oil pressure sender in the taco plate?

Thanks!

It will be tight,find the widest blade screwdriver you can to fit the slot.
In my collection of "make do" custom tools I have an old 19mm wood chisel ground to fit the slot for T1,T4 and 911 motors,never failed me,remember to hit upwards on the plug it will free some tension ,good luck.

No. The sender in the taco plate is oil temp, not oil pressure. WOuldn't do any good to measure pressure there, it would always be zero. (The oil is just sitting there in the sump; you need to measure it in one of the oil passages that has been pressurized by the pump.)

The usual way to hook up an oil pressure gauge is to replace the oil pressure "idiot light" sender that lives near the distributor on top of the crankcase.

--DD

Oops! Thanks for putting me straight on that Dave.

I popped the relief plug loose with a gentle tap on an impact driver

Thanks Dylan.

Are the thread on this all standard - meaning an over the counter gauge from O'Reilly will be correct?

EDIT - never mind - buying a kit with multiple adapters since I have several engines I could use this for and one of them should be OK for the 914.

OK - got the mechanical gauge on (nod to @Chi-town for confirming despite having 1,374 lines coming off it my oil pressure sensor was intact in the right place).

Cold at 850 rpm

Click to view attachment

Hot at ~850 RPM with cylinder head at 200 and oil at 180

Click to view attachment

Not looking so awesome...

I have NOT replaced the oil pressure relief spring yet.

Best to do it with engine hot as that is what really matters,what pressure did you get @ say 3k rpm with the oil cold.

Edit didn't see your next reply....that isn't good oil pressure

Yeah / seems like rebuild time.

What were the relief valves like ? and were there wear marks on the pistons and did they more freely on the case galleries ?.
Reason to ask is you have good pressure when cold which would indicate the pump is ok.

Hi - thanks for the follow up.

I haven’t taken the engine apart so don’t know. Wondering if it is even worth messing around with the oil pressure relief spring or if I should just pull it and tear it down.

My recommendation would be tear it down.

If you have low pressure, bearings are likely already torn up.

Even if you successfully boost pressure either with a new oil pump with more capacity or via relief valve. The damage is done and it will only continue to eat itself the more it's run.

Go take a look at my thread and you'll see an engine teardown that still had enough pressure to keep the idiot light off but has damage to both bearings and the crank. Rods to be torn down today.

That is good counsel, will go that path.

wondering if it has been run low on oil @ some stage,rod bearing have excess clearance and pressure loss there with warm oil,the bottom ends in these motors are pretty strong normally,regardless its a tear done to find the issues,hope it works out.

Thanks mate.

This (1/2" drive) tool is your ticket. The snap-on number can probably be cross referenced.

Click to view attachment

Click to view attachment

Ohhhh - new tool!

That would make short work if it.

Thanks.

The engines with the second relief valve at the back of the engine are famous for having hot oil pressure issues. I took the spring out of the one in Betty's engine and replaced it with a steel rod so it never will open. I figure it wasn't needed because the factory eliminated it in 75. Fixed the problem with low oil pressure when hot.

I would love to see someone with machine shop skills make up a plug that was one piece all the way from the piston to the plug. Then gun drill it and tap the outside hole for a pressure sensor. Put the oil pressure switch there, and the gauge by the distributor.

Hi Clay - I assume that includes all the 2.0l case engines?

Thanks!

IIRC... yes.

you mentioned that you don't know what was done to rebuild the engine . If it has a RABY cam kit installed it usually comes with cam followers that are drilled with a very small hole designed to spray oil on the cam lobe . That set up should be used with a HD oil pump because at high temps and at idle the stock pump can't keep up. I have two engines I built with the before mentioned Raby kit. One is a 1911 and the other is a 2056 and both exhibit the same low oil pressure at Idle when hot. I have oil pressure gauges and oil temp gauges in both cars but they both pump the proper oil pressure when running at speed , +/- 200 F I always get at least 10 PSI / 1000 rpm IE +30 psi at 3000 RPM. Both engines pimp about 80PSI when cold . I'm in Atlanta and use 20/50 "Driven Oil" By the Way both of these cars ( 914 and 912E) have been running this way for about 15 years with NO problems . Al

Thanks Al, helpful.

I don’t know the engine components on this one so planning on taking it apart and inspecting for damage AFTER I do a Hail Mary on the oil pressure relief spring.

I understand that if the pressure comes up some damage may have already been done but it seems like a useful data point to have before pulling it.