Been wantin an rx7 for awhile now....but havent had the money. I came across a decent looking 87 fc for $300 but it didn't run and was told it would never run again. I fooled them, after some quick diag and a fuel pump runs like a champ. So heres my question.

On a push rod motor oil pressure varies depending on RPM. I dont have a lot of experience with the wankel motor but im learning. Is the OMP (Oil Management Pump) pressure vary at idle?

Also.....What are some common problems associated with a slight choppy idle?

 

The RX7 has a normal oil pump just like a Ford or VW. The OMP or Oil Metering Pump is not the same thing. It supplys a tiny amount of oil to four oil injectors located on the intake manifold and the rotor housings to............................I'll stop here and just install two jpg out of the training manual and let you read Mazdas words on the Metering Oil Pump.

It is a real pump and does output pressure and its output does increase with engine speed. Delivered amount of oil is miniscule compared with a engines oil pump.

Series four metering oil pump shown in the jpgs attached.

 

$300, gotta love steals like that.

 

$300 is a steal for a fixer upper. Hopefully the body was in OK shape.

 

thanks HAILERS2 for the info it was really helpful, also....does the oil press. gauge on the dash supposed to fluctuate as well, even at idle?

And as far as the shape of the car. It was previously owned by an older woman. No rust and paint and are very straight. I gave the car a good bath and buff and it looks as good as new.

Thanks again fellars.

 

the oil pressure will go up or down,, for cold and hot oils at idle,, it should be fairly steady ,, and rise with rpm

if the needle is erratic,, the cause is usually that the dampening circuit is not earthed
if you go to the loom near the clutch fork on top of the box,, you may find a small black 2x1cm square block attached to a single wire
this is a condensor/cap and its for the oil pressure circuit
it SHOULD be bolted to top of the box ( in NA manual ) or to the firewall in other models

 

So from what I understand is that a rotary has 2 oil pumps....one like a conventional motor to pump oil to the motor and a stand alone OMP which feeds injectors that oil the apex seals and rotor faces in the comb. chamber which would explain why a rotary burns oil......

what would be an avg. oil press at an idle?

 

20-30 psi at idle with a fully warmed up engine.

I've never seen a stk gauge fluctuate. They are slow responding gauges compared to a mechanical oil guage.

If I had questions about whether the gauge is woking right..............I'd install a mechanical one even if only temp. SunPro's can be had cheap at the autostore. About twenty bucks or less. But you'd need an adapter to connect it to the *block*. Threads in the block are ??? 1/8 BSPT?? I forget right now.

 

mazda 1/8 BSPF is 28 threads, 1/8 NPT is 27 threads per inch and is the standard on aftermarket gauges