I can see the oil pressure dropping off a little from a really bad dowel pin leak, but if you have no other leaks and you aren't blowing large amounts of smoke out the exhaust, then it comes down to the the sender, gauge or the o-ring between the front cover/front iron as the usual culprits. As J9 stated, try a different oil pressure gauge and sender. If the pressure still drops, drop the oil pan, check the gasket on the oil pickup tube and replace both oil pressure regulators. Did you mod the regulators to increase working oil pressure?

 

Do they sell them at o-reilys? If so how much is it going to hurt my wallet, which is beaten to death so far lol.

Just to clarify too, Im using 20w-50 oil, 5 quarts of it in the pan since its technically a filter change, viton oil ring inserts have been replaced, all gaskets replaced (including the oil passage from the from cover), fresh rebuild (#3), starts, runs, oil pressure dies, after that, if i tap the gas to pick up some rpms, it dies as if theres no oil to complete the seal of the rotors.

 

No more ideas? Ive checked all these and nothing has worked. Ive cleaned the contacts on the sensor and wiring harness too, nothing changed

 

Compression on a running rotary is not heavily dependent upon oil pressure; it's dependent on the housing seals, which are not oilled at all, and on apex, side, and corner seals, none of which are hydraulically fed. They are oilled almost exclusively by the OMP, and on a freash rebuild the compression is not dependant upon oil.

If the engine is stalling under light pedal, something else is almost certainly the culprit.

Are you absolutely sure that you are observing a for-real oil-pressure loss, and not an ELECTRICAL loss that is stopping your guage, and then your ignition?

 

Im fairly sure. Is there any way to tell other than getting an aftermarket oil pressure gauge? I just have a hard time believing that my gauge would be completely accurate and normal and then all of the sudden die off. This also leads me away from an oil pump failure since if it was, it wouldnt have oil pressure ever.

So could this be the oil pressure regulators in the front cover and rear iron? I never took them off or touched them on my rebuilds.

 

Also, could it be the oil bypass valve in the beehive?

 

I'm not an expert on the beehive - - don't have one - - but AFAIK the only way oil pressue could cause an engine to actually STALL is if rotating parts are going unlubricated and seizing - - which is normally not a self-recovering event.

You can check your system voltage using an external voltmeter easily enough; see if system voltage drops off when the oil pressure does. Might tell you something, might not, but it's easy to do.

 

I have the feeling the stalling is unrelated. Probably just because the motor isnt broken in yet and when i was doing that, it was still cold too.

Ill call up my buddy mike with his multimeter and see what happens. Its just such a shame that I can't drive it. I keep seeing FBs on the road, makes me cry a little on the inside =P

 

that's why you need to try a different gauge! working fine cold and then failing when hot is how a bad sender will usually act.

 

Ok so I have to pick up a gauge, sender, and adapter kit from racingbeat correct?

 

You could maybe save money by using (maybe even renting?) a test-instrument-style guage, rather than something meant for permanent installation.

Something like: http://www.sjdiscounttools.com/kdt3343.html

Or you could use an adaptor and thread a panel-type guage sender into the original oil sender port temporarily for testing purposes.

 

yeah you're just testing to see where the problem is

 

But it turns out to be the gauge, wouldn't i want a permanent replacement anyways?

 

In that case I'd think you'd want to replace your stock guage with a good stock unit, but that's more a matter of choice than need.

It would bug me to have something taking up space on the dash that doesn't work, and something else somewhere else that does what it did. Not to mention having that no-longer-needed stock sender hanging off my engine.

I can't help it, I'm a purist. YMMV, of course.

 

I am too oddly enough haha. So would it be wise to get a new stock sender (assuming thats the problem) and see what happens?

 

If the sender is the problem, then replacing the sender will eliminate the problem, yes.

If the problem is elsewhere in the system (the guage itself, or electrical problem elsewhere) changing the sender out will make no difference.

Swapping parts until the problem goes away can work, but it gets expensive unless you get lucky.

 

Well I ordered the sender. That will at least eliminate that as the culprit. If that doesn't work, I'll have to throw a multimeter on it and hope for the best

 

i know this is an old thread but did you ever find the cause? pisses me off to read through a thread like this and there not be a conclusion

 

+1

 

seriously