I had a huge oil leak coming between the rear iron and the bellhousing on a transmission. I had a shop change out the rear main seal and the o-ring, but it is leaking again. I think the fix lasted a day at the most if that..

Can you guys help me troubleshoot this problem? My oil pressure is high reading beyond 150 psi at high RPM which has always been the case. My eccentric shaft is an aftermarket unit from Xtreme rotaries if that would be relevant.. the shop said the o-ring was badly damaged when they took the original one out so they thought they got the main culprit. It's possible that I have another source because the leak has not slowed down even a little bit, or the O-ring has blown again. Thanks in advance.

 

When you say the o-ring, are you talking about the o-ring on the rear stationary gear?

in pics of the old seal or new leak?

How long did the original rear seal last?
In what way was the o-ring damaged that they removed?

I will assume your shaft hasn't worn (new build), so a possible cause for you leak - incorrect instillation of the new seal.

 

Thanks for the reply. Yes I meant the stationary gear o-rng. I don't really know how long the original one lasted, because my oil pan has always had a leak that probably obscured any leak coming from the rear iron. The pan was fixed recently, and that's when I started noticing leak coming from between the transmission and the rear of the engine.

I don't have the original unit because the shop tossed it. I guess it is possible that shop didn't install it correctly.. they don't specialize in rx7. The leak is definitely coming from the rear of the engine because after I will pressure washed everything, I see oil coming from every orifice of the bellhousing including the starter holes, access window, and other misc subcentimeter holes on the bellhousing.

The motor has less than 2000 miles total at the most. Is there any other potential sources? This time, I probably should be there when the transmission comes off and have the engine turning so we can correctly identify where the leak is coming from. If there's any suggestions or tips, please let me know. Thanks

 

Possibility the instal wasn;t right. If I was you i'd pull the tranny and get in there with a big flashlight to check it out. Might be a crack somewhere.

 

Is there any chance too high of oil pressure could blow the seal and o- ring? Just brainstorming before I make trip back to shop. Thank you.

 

In addition to o-ring at the stationary gear, should I use silicon sealant for the mating surface?

 

https://www.rx7club.com/3rd-gen-gene...-leak-1097498/

 

One more thing to take into account if you are buying seals from anywhere that isn't mazda. just check to make sure the helix on the seal is correct. if it is in the revers direction the seal will effectively pump out the oil.

 

You mean the part number? I thought mazdatrix and Atkins only sold genuine Mazda parts.. as for the seal Direction, all i have to make sure is that the flat part of the main seal faces towards me / flywheel right?

 

I don't know what seals they use but what I was talking about you can see in this pic. the lines on a helix need to be pointing in the correct direction in relation to shaft rotation.

[img=http://s32.postimg.org/6g51dmg0h/710689.jpg]

If they aren't, rather than preventing oil from leaking past the seal the helix will effectively pump oil out past the seal.

 

boost going to the crank case can blow seals. food for though if you are boosted you should check the vacuum at the oil fill with cap off at idle, constant suction is bad. with an rx7 it would have to improperly modded to be this way though.

 

Can you provide more details on your engine?

were the rotors modified in any way? IE lightened, cut for thicker apex seals etc.

 

Thanks for all the replies guys. I can not check for vacuum in the crankcase now because I tore down everything. But here are the pictures of what I have. The engine is a triple rotor with FD rotor housings and rotors. The eccentric shaft is from Xtreme rotaries I think. By the way, does the stock eccentric shaft have a plug at the flywheel side? I want to change out the plug while everything is torn down, and I cannot figure out what the thread of the plug is.

 

Stock 20b shafts don't have a removable plug in the end of the e-shaft. If yours is a remanufactured shaft that has a removable plug installed, I would recommend ensuring it is sealed. as it will see full system oil pressure it is a potential source for your leak - if it was expect to see trace elements in and around your spigot bearing.

 

That is the RX8 rear main seal. Install the orange RX7 part.

 

What a bastard that little thing is proving to be, causing lots of issues for people.

Attention to detail will make or break you when cleaning, clearancing, porting, and building a rotary engine..... many think it's easy to do, but there's something to be said for a professionally-built high output turbo rotary

 

I talked with atkinsrotoaries about this.. they are the ones selling rx8 seals as compatible with rx7 rear main seal. the guy at atkins said they built over 10,000 rx7 engines with rx8 real main seals with no leaks. they say rx8 seals are made of better material which I don't disagree because rx8 rear main seal came out in one piece as opposed to rx7 seal which came out ripped to shred with all the pulling and pounding maybe he's exaggerating about the # of engines built, but I don't doubt they build these engines regularly... I'll try the rx7 seal from mazdatrix. will report back.