Well, it's happened once again... a major internal engine problem ...

My oil pressure guage is showing no more than 30 psi at 3000+rpm, and falls to like 5-10 at idle. When the engine is started completely cold, the gauge will read up to maybe 50, but for less than one minute, then it falls down again. I swapped out the pressure sender with another one that I have lying around, but I get the same results!

Any ideas on what could be wrong? I need to fix this ASAP to get the thing to pass smog too

any help would be greatly appreciated!

Thanks,
Manolis

 

^^bump!^^

 

look up the thermowax pellet in the excentric shaft...

When that thing fails it causes similar results.

My guage has been peaked @ anything over 1K rpm ever since my rebuild, then falls to nothing at idle. (750rpm) Swapped out senders with another one off a parts motor (unverified) and it shows nearly no pressure @ any rpm now, yet the motor sounds good stays cool, and pulls hard. Gonna grab a working sender (verified) tomorrow and see what it does then go from there.

 

thanks for the tip Jimmy! I believe that atkins rotary sells a little plug that replaces the pellet -- what do people think of those in general (bad for engine, ok??)

edit: Your problem sounds like it may be a bad guage. My guage, however, never moves beyond 30 or so psi except the first minute or so after a <very> cold start.

 

It could be a number of things like:
oil press. control valve or regulator valve, or even oil cooler by-pass valve.
In my case it was the oil pump, whenever the engine would get warm the oil press. would drop to around 3kg
at 3000 rpm and almost to nothing at idle.

 

what was actually wrong with the oil pump? i'd imagine that that would be a pretty gradual change (pressure slowly dropping)? Either way, mine's below even 3kg/cm^2 at 3k rpm (that's 42 psi, and mine's <30 when warm)

 

sounds like the front o ring... is your engine a rebuild? very common on rebuilds.

 

I actually made my own spacer rather than buying the atkins piece. (either will work)

My gauge worked fine prior to my rebuild and my pressure seems to be fine also. (siliconed the o-ring in place, sans gasket and washer for the front cover)

I'm guessing the solvents in the hylomar probably ruined the sender. (had it installed on the endplate durring rebuild)

 

isn't correct pressure 70 psi @ 2k

 

60 at 3k....

idle will be 15-30

 

Haynes says 70, I trust you but just lettin you know

 

ok, just checked FSM. says 64-78psi at 3k (while warm)

 

scott -- what front o-ring are you talking about exactly? the one on the e-shaft bolt? if so, how could that thing fail?!

 

I'm not too sure... there is an o-ring on the front cover that seems to fail. causing around 30psi at 3k...

 

ahha... I'll go looking through the FSM for that one. Anybody know which one it is exactly?

i'll figure this out sooner or later...
Manolis

 

dammit, looks like you were right scott. Mazdatrix's description of this http://www.mazdatrix.com/faq/oring.htm matches my symptoms perfectly

 

I may sound dumb here but, how old is your oil? It gets thiner over time.

 

changed it like once ever 10 miles the last two times (10W-30 change in a panic, then swapped to 20w50 when that didn't help)... i thought that was it too, but it wasn't

 

I'm going to revive this thread... did you ever figure out your problem? I just started getting the same symptoms.

 

I did as a matter of fact! It was that damned little o-ring in the front cover ! a $1.90 part, oh well...

Check out this page: http://www.mazdatrix.com/faq/oring.htm

The interesting thing is that the teflon support ring is not in the mazda parts catalogue (the parts dept. couldn't find it, and the guy there was really lknowledgeable). As far as mazda is concerned, that part doesn't exist i guess Anyway, no big deal 'cause i stole my friends old one

Anyway, oil pressure is back up between 30 and 60 psi at all times (yeahoo!)

Thanks,
Manolis

 

Where did you get the O-ring, and did you replace it?

 

yes, i replaced the o-ring. I bought it from the local mazda dealership. I'd imagine that mazdatrix has one too.

 

Okay, I have to ask - how hard is it to do this procedure by yourself? I seem to have the exact same symptoms as you describe, i.e. low oil pressure at idle (probably between 10-15) and only about 30-35 at 3000 RPM. Forgive me for being "uniformed" about the rotary engine - just give me some insight as to exactly what is involved at replacing this "o" ring and exactly where is this "front cover" referred to located? Thanks in advance! Also - besides this fix, are there any other things that cause this low pressure oil reading. The engine has been running great, short of the "common" no start problem, once.

 

It's not that hard to do, just a pain in the ***. You have to remove (for a turbo car):

Radiator
Intake manifolds
smog pump
water pump
PS bracket (unless you're lazy like me and didn't put the bolt in that attaches it to the front cover )

First thing i'd do is change the oil

Second thing i'd do is swap out your pressure sensor, just in case

Third thing i'd do if it's neither of those things is tear the front cover off and inspect everything there. If that o-ring is still there, then take the oil pump apart and make sure it's within spec.

Good luck!,
Manolis

 

Why do you have to take off the intake manifolds?