OMP - only working on one side? (port?) 12a
 

1985 RX-7, 12a, Stock. The OMP appears to only be pumping oil out of one channel. What might cause this? My lines are fairly new (less than two years). I can see the oil traveling up the one line, but not the other. Connections appear to be good. Thoughts?

I guess I should ask, is this even possible? I wouldn't think so, but for seeing oil only in one line...

have you rebuilt the omp?

It's possible - most likely cause would be a clog inside the pump body on the one side that's not delivering.

MOP rebuilds are not hard; mainly consists of disassembly, cleaning, and replacing some o-rings and soft parts. Kits are available.

Do the actual MOP test in the FSM first, though, rather than trusting that you are seeing the oil move in the lines. Could save you a lot of work for nothing.

Thanks. I have not rebuilt it. I'll look into a kit.

pineappleracing.com has a rebuild kit with a how2 DVD for all of $25-ish.
Your lines will be a bit frail so care on removing. At least one of them is NLA…


Stu Aull
80GS
Alaska

Any pointers on replacing the gaskets in the 12a OMP? Thanks!

Like I said above….

:D

Stu Aull
80GS
Alaska

Thanks, Stu - The pineapple video looks like it's for the GSL-SE OMP only. I suppose there isn't much difference, but the body of the omp surely looks a lot different. I was looking for any pictures of disassembly. I'm a visual learner. :)

While you're troubleshooting, take a close look at the intake plenum lines on the oil injectors to be sure they're hooked up to intake vacuum. The SE has a 1-to-4 splitter which takes a single intake vacuum line and splits out to 4 oil injector lines. These lines are needed to pull the intake 'pulse' from the ports opening and closing rapidly to supply an oscillating vacuum on the oil injectors - which creates a mild 'spray' effect at the nozzle of the oil as it's pushed up by the OMP. This spray goes into the intake air more easily instead of just running down the inside of the manifold.

The SE is has the 2 additional oil injectors on the rotor housings at the top to spray oil onto the passing apex seal, which was designed to help with apex seal lubrication and increase durability and engine life.

I've rebuilt 2 OMP's over the years, and only because the main 'O'ring which seals the OMP to the front housing had hardened up over time and allowed oil to leak past, making a mess of the engine bay. I think there are only a few small 'O'rings and the larger sealing ring to a rebuild. It's a very simple system and not much else to be done.

As others have stated, be VERY careful with those lines - they're brittle, fragile, and getting to be unavailable!