So i'm prospecting a 94 Touring RX7 w/ ~62k mi. The car has not been modded in anyway -- we took it out for a WOT run and i checked the boost pattern with an autometer guage (10-8-10). The only problem was when at idle, something started smoking under the engine (passenger side from above). We concluded that it was his oil gasket leak, and that the oil residue was burning -- after the run, there was no more smoke (it all burnt out?). Thats the only known problem in the service history other than a knock sensor replacement and a boost sensor(?). what do you guys think?

 

ive got the same problem. I did a search on this and found out that it could possibly be the silicone coupler between the y-piep and the intercooler pipe. Thru its design the engine sends oil thru the intercooler to lubricate the apex seals and if the coulper is cracked or loose in some way then it can allow oil to build up on the y-pipe and smoke. this will come from the exact area your talking about. I suggest you take off the three top hoses comming from the airbox and this will allow you to get to the coupler which is only held on by two hose clamps. Take offf the coupler and inspect it for damage. If it's cracked replace it BEFORE you buy it to see if this fixes the problem.

 

What in the hell are you talking about?

The turbos and intercooler have NOTHING to do with lubricating the engine apex seals.

True, there is often a small amount of oil in the intake piping and IC. This is due to oil blowby on the turbo compressor wheel...not a good thing, but a little is normal on any turbo car. Puddles of oil here indicate turbos on their way out (common with stock twins with over 75k miles). This was not a "designed in" feature though, it represents wear and tear.

The engine has an oil metering pump on the front that pumps oil through small plastic hoses and directly injects via 2 small ports on top of the block to lube the apex seals. This is a feature of all rotary engines, and has nothing to do with the turbos or intercooler.

You are correct in that the Y pipe to crossover pipe connector often fails, and becomes a boost leak. That is obviously not the case here because he has proper boost according to his test.

To the original poster, if the smoke you saw was from the tailpipe, it is likely from the turbos themselves smoking internally, another common sign of worn turbos on these cars. IF it was smoke in the engine bay, oil is contacting the hot exhaust from a leak somewhere. IF the oilpan leaks severely enough, this could well be the case.

OIlpan leaks on 3rd generation engines are VERY common, and less than 10% of all the 3rd gen cars (stock or recently rebuilt) can claim NOT to leak oil. IN fact, even as a rebuilder and installer, often times my best efforts to seal oilpans are defeated because the block's pan mating surface is never 100% flat (due to the stacking nature of the engine's parts) and warped pans from prior removals and reinstalls as well as overtorqued motor mounts (which bolt through the pan). While clearly not desireable, an oil leak on a 3rd gen oilpan is almost an accepted fact of life when owning the car.

 

Thanks for the reply guys:

The owner has taken to a service shop in PHX and they said it was the oil gasket, but its not a big leak--but a leak nonetheless, which would cost around 400$ in labor ... and from what i've read about 20$ to do-yourself .. except id need to take out the sub frame of to get thru to the oil gasket? is this simple ?

 

Yes, it is straightforward but not easy. The engine must be supported while the subframe is dropped down to gain access. IT is possible to change the pan with the frame in place, but quite difficult to do it that way.

Even after the job is done, dont be surprised if it leaks a bit.

 

bah, thanks guys. as far as problems are concerned thats pretty much it. i found a rx-7 specialist in town (tucson) which i didnt know existed (found out from some other RX-7 owners) heard he's been working since the rotary came out. its a kinda cute shop name...

Rx for your 7 .... lol

again thanks guys.