The engine is a fresh rebuilt 2056 stock D-jet engine running Brad Penn 10W40. Once the oil gets warm the idiot light comes on and the oil pressure gauge (electrical VDO) goes to almost nothing.

Thinking about trying Tangerine's Oil pressure relief valve:

http://www.tangerineracing.com/oilpressurerelief.htm

Is it pretty easy to install with the engine in the car? Does it slide in easily or does it need to be pressed into the bore?

The description says it bypasses the oil cooler so is the oil always going through the oil cooler even on cold start?

One more note. I misplaced the engine's original plunger and spring assembly so I bought a used one. I have since found the original spring and plunger. Just wondering if anyone thinks putting the original part back in will fix the problem. The original engine was built as a 1.7 and I don't recall it having this problem.

you should at least try the stock spring and piston.

The tangerine solution would work also and might help.

Most likely you have worn rod bearings. I am now on my 3rd motor after showing the symptoms you described (race motor). Hope the correct parts will fix it.

The problem might be the oil weight. I think most people are running 20w50, not 10w40.

Might try increasing the idle speed a touch, oll pressure very sensitive to pump speed.

Try running 20/50 and see what happens,thats what you should be using anyway.
Your issue is a serious one so you need to get yourself a mechanical gauge so you can exactly know what pressure you have,I won't run up any new build engine without a mechanical gauge hooked up.
Did you measure the crank and replace rod bearing during the build ,reason I ask is this oil pressure issue is common but mainly on worn high mileage engines,it can be related to a worn oil pump also.
Try putting the original spring and plunger back in,just make sure the piston moves freely in the bore with a little oil on it,good luck.

Yes, new bearings all around and the crank was measured for matching bearings. The rods are new H-beam and I plasti-gauged all of them at 0.0015".

During break-in I used a mechanical gauge and after the break-in run the engine settled at 1200 rpm 40 psi (mechanical gauge) with 30W break-in oil. I used a thermocouple to measure the oil on the dipstick at 125F.

I will try the 20W-50 and reinstall the original oil relief assembly at the same time.

I'm surprised I'm not getting more encouragement to use the Tangerine product. Does anyone know if it's pretty easy to install or is it difficult to press in upside down from under the engine?

Hi, another variable to consider is oil temp. Pressure will drop and the oil gets hot. I;m running a 2056 with d-jet and Raby 9590 cam. Newly rebuilt motor, d-jet not optimally adjusted and running lean and timing not optimally set all can result in increased oil temps and decreased pressure especially at idle.

For me a combination of the below worked.

1. changing exhaust so I had a common collector and could put in wide band oxygen sensor and then adjusting the mix after replacing the diaphragm in the MPS with the excellent tangerine diaphragm (they are all bad if original).

2. Get real oil temp gauge and head temp gauge.

3. Finding timing that the engine likes, mine was around 28-29 at 3500. Some have needed less than 27. I did this trial and error, change and test drive as I do not have a dyno. Watching both oil and head temps.

4. Check and see if your engine had the pressure relief valve which I think is under cylinder #1 on the side (typing from memory) . Not all cases had them. Make sure oil is not getting past at normal pressure. Mine had a copper plug put in by PO who had been running hydraulic lifters. The seat in there can be rough and leak.

5. Putting some miles on the engine.


There are lots of threads dealing with all of the above.

I did buy and install the tangerine oil pressure relief valve which is a very cool product, but it did not help my temps and low idle pressure.

I use the tangerine valve. easy to install, just as easy as the spring and piston.

what is good is that it rides in a smooth bore with a tight fitting piston that will seal against an o-ring.

Try the stock one and oil weight first. (its cheaper).
it is a good product otherwise also.

So I thought I'd follow up in case anyone else has the same issue and to maybe solicit criticism from the experts in case I'm doing something wrong.

I tried everything above and none of them increased hot idle oil pressure. The Tangerine device increases max oil pressure, but doesn't seems to change anything at hot idle.

It appears it was more a measuring issue. I removed the PCV valve from the plenum and got approximately a 4 psi increase. So perhaps I have a defective PCV valve? I've read some race cars pull vacuum on the crankcase to increase oil flow even though it results in decreased gauge pressure.

As advised above, I stuck a mechanical gauge in parallel with the VDO. At cold oil pressure the VDO read at about 12 psi low; 60 vs 72 psi. At hot oil pressure the VDO was reading ~6psi and the mechanical was at 12psi. I used a 12" kitchen thermometer to get accurate oil temperature at 220F down the dip stick tube. I had to drive it around a bit on and off the freeway to get to that temperature.

Thought I'd add this follow-up in case anyone else has this issue. The VDO inaccuracy seems in line with what Ratwell says.

I did a rebuild on my engine and everything was in spec. still had a light come on occasionally at idle . 137K miles on the case.

Installed the Tangerine piece and all my problems went away.

It won't hurt,