Long story short, I have a RX-8 stat gear in my 2nd gen engine and it keeps leaking oil.

I recently rebuilt my engine (HBP w/ haltech E6X) and decided to put in the RX-8 stat gears with window bearings. From what I have read, you have to put RTV of some sort where the o-ring would normally go since the RX-8 places the o-ring in the housing instead.

I was driving the car for a day or two until I noticed the clutch slipping when boost hit, plus some smoke coming from the engine bay. I ended up discovering that oil was coming from the rear gear. Since it has a brand-new rear main seal, I assumed I hadn't done the RTV correctly. I ended up pulling the engine, pulling the stat gear, and putting a large bead of Right Stuff gasket maker in the location where the o-ring would go. I put it back in and after a few days, clutch slipping again and signs of oil leaking. What am I doing wrong? When I pull it again, I'm going to take it to a machine shop and have them machine in an o-ring groove like the stock gear, but I want to make sure I'm not over-looking something because I really don't want to pull the motor again.

 

Also, not sure if it matters but I'm running about 85-90 PSI oil pressure.

 

Ideally you will want to have the rear housing machined rather than putting RTV in it so it seats like how it would in a Renesis.

 

I was just going over everything in my head, and I think the problem may have been that I got oil on the mating surface. I didn't think about it at the time, but there was oil leaking out of the gear when I was putting it on. I'm guessing that engine oil being present would mess up the seal.

 

If you tried fixing it once and that didn't take,why not just go with an Rx7 gear?

 

I thought the RTV went on the flange to the inside of the bolt holes like on an oil pan for example not the O-ring groove around the gear. You could put a three window bearing in an Rx7 stat gear and call it done.

 

Thought define auto was selling machined RX-8 stats so that O-rings could be used. You might want to check with them if you want to keep using the RX-8 gear.

 

are you using an rx-8 e-shaft?

I thought the bearing on the rx-8 rear stat gear was tapered to match the rx-8 e-shaft... I wouldn't think you would want to run in with a normal e-shaft.

I used RTV and mine doesn't leak that I'm aware of... but you should just have the stat gear machined... I would have it I wasn't pressed for time.

 

That is a good assumption. Provided that all surfaces are clean of any oil residue and dry, a thin bead of "right stuff" where the o-ring would normally be should be just fine. Obviously you'll also want to give your sealant time to cure before adding oil back to the car and/or pressurizing the system.

 

The 8 e-shaft doesn't taper where it would contact the bearing. You can swap out bearings on the stat gears w/o issues. The two main issues with using an 8 rear stat on a 13B are that A) the o-ring locations are different, and B) the oil passage on the 13B rear iron is slightly off from where it is located on the 8 stat gear.

A* can be fixed with a little RTV (if properly applied) and B* can be fixed with a little bit of careful dremel work.

If you're going to run an 8 e-shaft than, at the minimum, you should also press 8 bearings into the front and rear stat gears.

 

I was in a rush because I only had that one day to pull the engine and replace it before the holiday insanity started. I dremeled out the passage to match and ran oil through it to flush out any shavings that weren't blown out by compressed air. I wasn't thinking and didn't let the oil drain properly, and when I turned the gear around some leaked onto the mating surface.

I have a history of rushing projects and screwing stuff up. I was super careful on this one on the initial build, but I rushed too much on the fix. It wouldn't be complete without some sort of screw-up, and this one is much better than chipping an apex seal like my last motor. I've got to take my intercooler, TB adapter, and TID to the machine shop to get modified, so I'm just going take in the stat gear at the same time.

As for putting a 3-window in the FC stat gear, isn't there some extra modification required to put in that bearing? Plus, I got both bearings for 80 bucks on e-bay, so there's also that.

 

That I'm actually not sure of, I'm afraid I may have spoken out of turn on that one... All my experiene is with the FD motor (though I've got S4 N/A rotors in mine.. does that count?? ) running an RX-8 E-shaft and gears.

 

Yes. There is not a 360° oil galley in the FC stat gear. Without it, a multi-window bearing is useless.

The RX-8 should not leak with Right Stuff if everything was cleaned and properly prepped before install.