K Background: I have an 85 GSL. Undergoing rebuild at the moment.

People recommended doing oil pressure mods if the bearings were being replaced which they are.

Searched. Found alot of threads saying mod the OPR but non actually saying how/what to do. I seem to recall you shim it with washers, but how many of how thick? I can't seem to find that thread anymore.

In one of the threads Wacky told someone to PM him to know about it.

As well, it was said that a GSLSE oil pump is better than the GSL. Why is it different?

If i just missed the right thread can someone point me in the direction of it?

Cheers

Jesse

 

K well supposedly the SE oil pump pumps more oil but I think thats make believe because in the Mazda parts manual they are identical part numbers, and yet in the comp parts section it says that the comp rotors are 17.5mm; bigger than stock EXCEPT SE.

WTF is going on with mazda part numbers haha.

But still about the regulators.... From various sources, RB and Mazda it says I need to shim the Front regulator 1/8". How much do I shim the rear regulator/can I do that, or do I need a different regulator or do I just shim the front?

 

Yes, the 13b pump is better than the 12a. I got it around here somewhere, hold on...

 

Oh and I have heard of tapping/chopping the top of the regulator down for the same effect as shimming it with washers.

 

I'd be more comfortable shimming if the effect is the same/clearances are all fine.

It seems for the front needs to be shimmed 1/8"

What about the rear?

 

Oil pressure mods:

Remove the screen on the pick up tube and flair out/trumpet the end of the pick up. Just make sure you don't drop a nut in the oil pan or anything

Clean up the oil galleys sharp corners, and smooth the junctions from the drilled passages and ports below the stock pump land area. Practice before trying on a good engine.

Dry sump if you have the $$$$$

Baffle plate

Tacking on a big washer on the end of the pick-up tube to get rid of the vena contracta

 

Also, using straight oil and not 10w-30, 20w-50 etc. The plastics they use to get the weight up when warm foams up so bad.

 

Hmm. Ok thanks Jeezus

 

Np. I have to do more digging on oil cooling and mods anyways

 

To obtain a high oil pressure, you have to slighty smack the tip of ROPR to stiffen the spring, and at the same time, shim the regulator on the front cover.

 

Aha, i knew you were lurking somewhere. Thanks wacky!

 

sorry, took for me to resp. I havent been on board lately.

 

I just did this research myself...here is what I found:

http://www.rebuildingrotaryengines.c..._Oil_Regulator

Rich

 

Thanks for the link Rich.

I had another question that relates. I have access to second gen 6port 13B parts. Am I able to use either regulators from those engines/is there anything to be accomplished by doing so?

 

Hmm sounds like i gotta start messing around with the oil system on the extra block i have.

 

There is nothing to be gained. Those engines had bigger oil pumps to accomplish, with stock pressure, what we are trying to do with raised pressure on our smaller oil pumps.

 

Are you saying I should not have just done this mod to the supercharged 13B 6 port in my project car? The oil pan is still off, so if I need to revert now is the time.

Thanks,
Rich

 

Check out Jeff's post:

https://www.rx7club.com/1st-generation-specific-1979-1985-18/same-year-12a-different-oil-pump-housings-should-i-use-711600/

I am pretty sure that he is right on and that the 83-85 12As have the same pump as the SE. I have seen other references that they are the same, too. I don't have a 83-85 12A pump to measure, but they show as the same part number, have the same wear limits in the FSM, and the FSM does not note a difference in size/capacity between the 2. I'm pretty sure that the SE pump being bigger/better than all 12A pumps is just a myth.

Anyway, the larger (17.5mm) pump will work in any '74-'85 12A and that is what you should run. Mazdatrix only carries the 17.5mm pump since it will work for all years.

 

Tell me exactly what you did and what your goals are. I can give you advice.

 

My goal is to make sure I have sufficient oil pressure. What I did is exactly what they do in this article:

http://www.rebuildingrotaryengines.c..._Oil_Regulator

I smashed the end of the rear oil pressure regulator to effectively stiffen the spring, then shimmed the end cap on the front oil pressure regulator.

I have no reason to think my oil pressure is insufficient...I replaced the oil pump when I rebuilt the engine about 3 years ago. I just blindly followed the advice on that website: "This modification would be for street cars, or race cars". I have a blower on my car, and I replaced the bearings when I rebuilt the motor, so just want to make sure I have enough oil pressure.

Thanks,
Rich

 

You will have plenty of oil pressure (perhaps too much lol). As for volume, did you get a 17.5mm oil pump? Or the dumb 12mm type?

 

Thanks jeff20b - I am somewhat concerned about too much oil pressure with the modded regulator. I had an oil leak problem before, so I assume it will be even more likely to leak now. I'm trying to make sure all possible sources are sealed off, but that can be difficult. I think the biggest problem is where the return line from the blower enters the front cover. I tapped it and threaded an elbow into it that the hose clamps to. I think it was leaking there (from the threads). I'm not sure what is the best way to seal that off. I think I used plumber's tape before...now I have plumber's paste (I think that's what it's called) on the threads, but don't know if that'll work.

I don't remember which oil pump I got...don't even remember for sure if I got it from MazdaTrix or BlackDragon, but can probably find out tonight.

Thanks,
Rich

 

Look at the oil pump. Take pictures. Show us. Maybe I can tell you which one it is. The high volume one has a thicker housing.

The oil return line often will not leak because A. it's under no pressure and B. it's gravity fed into the sump. The SC 510 has a slightly loose return fitting because the owner originally cut the threads too deep and the fitting bottoms out before it gets tight. I tripple wrapped it with teflon tape and it doesn't leak. Your leak is probably from your OMP dripping down on things and making a mess.

Keep an eye on your oil pressure if it tops out past 100PSI when cold, kep the revs low until the engine warms up. Or use thinner oil like 10w30 or something.

 

Thanks again jeff20b - I'll have to see if I have any pictures of the oil pump...I've already put the front cover on and would prefer not taking it off again if I don't have to. I probably have some pictures from when I rebuilt it though.

Yea, I couldn't tell for sure if the oil leak was from the OMP or the supercharger return line. I rebuilt the OMP so that should be taken car of now. I'll also do a better job of sealing the omp lines at both ends, where they connect to the OMP at one end and the "injectors" at the other end.

Rich

 

Oil pump pictures attached.

Rich