falcon63

First I would like to thank various members for their help and direction in getting my 88 vert to meet CA emissions standards.
My current, and continuing problem is low oil pressure. I've owned this vert for six years with a low oil pressure problem. The car has always driven well and never acted like anything was wrong. After getting it smogged, I took it to my local Mazda dealer in Fresno, CA to install a thermal pellet replacement from Atkins Rotary hoping that this may solve the problem. Much to my dismay, their technician advised me that I had excessive oil consumption and the engine was "blown." Now, I have been replacing a quart of oil about every 1000 miles, which I didn't think was excessive, but he was convinced I was wrong.
Are there any rotary engine specialists in the central CA area????
Based on my looking at the workshop manual, could my low oil pressure be caused by a faulty spring in the oil pressure control valve or a faulty oil pressure regulator valve. To the best of my knowledge, they are the original parts on a car with 175,000 miles. I mention these components, because they are relatively easy to access after dropping the pan. If it's the oil pump itself, I don't know where to go, since I don't have the skills, time, or inclination.
At cold start, the oil pressure gauge reads just short of 60 psi and gradually drops to 30psi or slightly less as it warms up. At 3000 RPM cruising, it's at 30 psi.
Any help, advice, or condolences would be greatly appreciated.

Stanis

iTrader: (2)

It sounds about like mine. Mine has been behaving like this for 5 years so I think it's safe to say, it's okay. When cold I get 55-60 psi. As it warms up I get 30-40 psi at cruise and at idle I have 15-20 psi.

Icemark

For shops in your area, post in the west regional section of the board.

Did you replace the e-shaft thermo-pellet or not?

It sounds like a bad e-shaft thermo pellet or a major internal leak (which usually would be eating more oil than 1 qt every 1000 miles). What are you using for oil (should be Castrol GTX 20W50) and oil filter (should be OEM Mazda)?

spot_skater

Rule of thumb regarding oil pressure is 10 psi per 1k RPM.

And a quart of oil every thousand miles or so, if driven relatively hard, is normal. If it's just burning more oil it could be due to the oil control rings inside the motor being old. Do a search on the forums for that and get some reading in, mang.

And get a compression check. If you're not having any driveability issues (huge loss of power?!) or blowing white smoke (blown coolant seals) all the time, I would say your engine is in good shape.

Probably just getting old and tired.

James

falcon63

I had the e-shaft thermo pellet just replaced. I'm using Castrol 20-50 GTX in the vert as well as my 87 Carrera 3.2. No driveability problems, no blue smoke except a small puff at start and definitely no white smoke. What about the oil pressure control valve. Could the spring have lost it's elasticity and as it warms up, opens up and doesn't maintain oil pressure??

RETed

Did you get a look at the spark plugs?
Excessive oil burning will be obvious at the spark plugs.

Second, that mechanic you went to is an idiot...at least with rotary engines.
One quart per 1,000 miles is still within the normal range.

Third, are you looking at the stock oil pressure gauge?
Those senders are notorious for failing.
If it hasn't been replaced recently, it's a good idea to replace it now.
Confirm with a good, mechanical (oil) pressure gauge to confirm you really have problems - it doesn't sound like to me.
If you really had low oil pressure problems all these years, the engine would've died on you by now...


-Ted

falcon63

I agree, the technician is an idiot, and he is the RX7 expert, since he OWNS One.
That's why I'm trying to find a competent technician somewhere between LA and SF. When i originally bought the car, I was concerned and had the oil pressure checked. The mechanical gauge and the gauge in the car matched with what I thought was low pressure. The compression was about 80 psi in both rotors. I figured that I'd have to rebuild it shortly, but that was 6 years ago and nothing has changed. I replaced the plugs when I got it smogged two weeks ago, and the old ones showed no fouling, so I don't believe that I have an oil consumption problem. Any thought on the oil pressure control valve/spring???

RETed

Check list for low oil pressure problems...

1) Change the oil - oil diluted with fuel is the culprit; cheap and easy to do

2) Check sender - already covered that

3) Oil thermo pellet - I hope the mechanic did this properly

4) O-ring in front oil cover - PITA and labor intensive for a stupid o-ring

Other less common culprits:
* Oil thermo pellet in the oil cooler failed, causing oil to bypass the oil cooler core

Everything else is almost impossible to kill.
Both the oil pressure regulators in the front cover and the rear iron are practically bulletproof.
These are simple spring devices and almost impossible to destroy.

Unless the engine was opened up, you're basically limited to the above.


-Ted

falcon63

Thanks Ted,

I'll try your recomendations and go from there. Since some of these are a PITA and I don't have the skills or time, do you know of a mechanic that's competent in the central CA area?

RETed

Sorry, wish I could give you a recommendation.
Might want to try the West section?

Is that guy Rick in San Jose still around?
Rotary Reliability?
Or am I getting them all mixed up.


-Ted

InsomniacFC

iTrader: (4)

There are quite a few rotary shops up in the bay area if you're willing to make that jaunt. Rick's Rotary or PR motor sports are a good start, but i'd check this list out first....

https://www.rx7club.com/showthread.php?t=573179