TheChadster

My oil pressure is 10psi at idle and less than 40psi at 3k rpm when warm.

I have taken the following steps thus far

1) Replace sending unit

2) Install aftermarket gauge when the stock sending unit threads on

3) install atkins solid thermal pellet.

None of these appear to have made any difference.

Anybody have any ideas on the next step.

Thanks in advance,

Chad

gsl-se addict

iTrader: (3)

I assume the aftermarket gauge read the same values? What oil are you running? Is the engine stock? If the engine has been open, someone may have installed larger oil jets, which would decrease pressure.

TheChadster

The engine has been rebuilt, don't know if the jets were replaced. What does the oil pressure behave like in an engine with the jets replaced.

Mine does the following:

At startup the pressure goes beyond 100 psi (100 is the max my gauge will display).

As the temp rises, the pressure drops until it seems to settle around 1 psi per 100 rpm.

Does that seem to be in line with an engine with the jets installed?

I have not driven my car since I put this engine in 10 years ago and I would like to get it going again.

TheChadster

Today I tried a 2nd aftermarket gauge

Replaced the oil with fresh 20w50

MazdaSpeedDan

iTrader: (4)

That is very high

TheChadster

High??? 35psi at 3k rpm and 50 psi at 6K

TheChadster

7-8 psi at idle

Sgtblue

iTrader: (16)

IIRC, the FSM specifies 50 psi at 3k minimum. If your gauge is accurate it's low...especially with fresh 20w50 in relatively cool weather. You've tried everyhing else I would have suggested. If your confident none of those things are still suspect, the only other thing that comes to mind is that the oil pump is worn and should have been replaced with the rebuild.

TheChadster

I have tried 2 oem sending units and 2 different mechanical aftermarket pressure gauges all show the same readings.

My question is this, If a car has the oil jets on the e-shaft replaced, will the car still hold 50lbs pressure at 3K rpm?

gsl-se addict

iTrader: (3)

See what it says under "eccentric shaft oil jet":

http://www.mazdatrix.com/boil3.htm

I haven't used these jets myself, nor do I own an FD, but it could be the problem. However, the low pressure at the higher RPMs makes me think it is something else (oil pressure regulator, worn oil pump, etc.)

TheChadster

According to Mazdatrix... " This oil jet replaces the factory checkball and spring.
These should be used in full race engines only, because the idle oil pressure is noticeably lower".

I still have my 81k origonal engine with everything attached. It had good oil pressure when it went. Looks like I need to pull my engine back out and play matchmaker.

Sgtblue

iTrader: (16)

One other thing came to mind over night that might contribute........an obstructed screen/pick-up tube in the oil pan. During rebuilds it's not unheard of that too much sealant is used on the pan/block interface. Some of it get's squished out and ends up in the screen.
Just thinking out loud here. It's not a particularly easy job, but you can drop the crossmember and remove the pan to check without removing the engine.

TheChadster

So I decided to road test her last night to see what else I may want to look at while I have the engine out. I kept my eye on the pressure gauge and it never dropped below 60 at 3K. And I was driving for over 45 minutes!!! Does it matter when taking these readings if the car is moving or not???? In the driveway, I won't let it run for more than 10 minutes because I get scared when I see the pressure dropping near the 35psi mark at 3K.

ladywoodrx7

i have a similar problem with my 92 efini rx7 rhd. the gauge is in metric since the car was imported here and at idle the car surges and the rpm revs up and down, also it reads around 2 kg-cm2 and at cruising speed goes up to 4 which is in the middle of the gauge roughly.I'm curious to know if that is low or what. the car is completely stock, minus a cheap cold air intake and exhaust. i just got the car not too long ago and im not sure what the previous owner has done to this car. it has 103,000 km on it (64,000 miles)

Sgtblue

iTrader: (16)

The surging idle might just be (likely is) a vacuum leak. Fix that and see what you get.

As mentioned above, the FSM specifies a minimum of 50 psi at 3k rpm. Use any conversion table to see how your's compares.