What is the normal oil pressure for an 87 TII at idle? My oil pressure gauge reads about half way to the 30 psi mark, so I guess its about 12-15 psi, which seems low to me. I have to hold the revs at about 1600 to get it to come up to 30 psi. At higher rpm's It holds about 45 or 50 psi. What determines the oil pressure on a rotary engine? Is it just an oil pump issue or do the bearings come into play as well? My engine does have about 140,000 miles on it , and I know its not what it used to be, but it still runs strong and I'm not rebuilding it until I get several other more pressing things done to the car first, or I guess if it completely blows up I'll do it! Is there anything outside of a rebuild I can do to increase my oil pressure? Thanks guys!! :1party:

 

Front cover O ring seepage or failure...

More common on the series 4 motors...

Mazdatrix has a great write up on it...
http://www.mazdatrix.com/faq/oring.htm

 

I can verify the results of installing the front cover o ring wrong, and it is similar to what you describe. Before going that route you should check the oil pressure with a mechanical gauge. They can be had for 20 bucks or less.

 

Believe it or not, 12-15psi is the low end of "in spec" oil pressure at idle.

As long as it has decent pressure over 3k or so, I wouldn't start fixing what ain't broke. I personally wouldn't worry about it....

 

PEEJAY has a good point there. I'd bet if you put a mechanical gauge on the car you'll find you have considerably more than the 45 to 50 psi. If you find that to be the case, it is possible to take the sending unit apart and adjust the *cam* so it will read closer to real pressure. Or you can check it with a mechanical gauge, confirming the pressure is better than that shown by the factory unit, and take that into consideration when you look at the factory gauge in the future. EDIT: Whoops, forgot to mention the factory gauge and sending unit suck. There is a place in the manual that insinuates if you put a 142 ohm resistor on the wire to the sending unit, and put the other end to ground, the gauge should read 60psi.

 

My idle pressure holds at 20psi for a little bit then drops to 10-12psi and if you let it idle for a few more minutes, it will crawl up to 20 again. The sending units suck big time. In my 85 SE, the pressure would start to drop at higher rpms to about 45-50psi. It did that for a year and now it started to show the right readings again. Don't worry about it too much. Also, if you use 10W-30 oil, it will give you lower readings.

 

There's another problem that's possible that most people overlook...

http://fc3s-pro.com/TECH/HOWTO/OTB/otb.html




-Ted