No Exhaust Sleeves
 

im rebuilding and everything is going fine except for the engine had no exhaust sleeves....engine was running fine before the rebuild decision other than coolant leak....what would be the bad effects, if any, would there be of running without the sleeves? yes-no-maybe?:goodrebuild:

more noise?

I have looked into this myself and didn't find any reason it will harm anything.

https://www.rx7club.com/rotary-car-p...sleeve-636053/

I have a old school set of 13B housings and i took them out for better flow because the port is small with them in.

welcome. :)

increased turbulence.

Mazdatrix 86-92 6-Port Exhaust

Racing Beat Rotary Tech Tips - Exhaust Basics

Yes ^^^ increased turbulence i wouldn't think it would be much.....That's the only down fall, but i was thinking along the lines of back pressure would not be more than a turbo.

Some people seem to be worried about temps, but hot is hot. It would be the same temp under the sleeve as inside it. I kinda think they put them there to pass emissions tests...a place for gas to settle and burn.

Compare the inlet of your manifold/header to the diameter of the stock exhaust port sleeves. Then compare the inlet of your manifold/header to the diameter of the rotor housing with the sleeve removed. Then tell me what you think.

thanks guys that's is what i thought from reading my literature i bought but hey, it never hurts to get a more knowledgeable opinion right?

I drilled out some sleeves and inserted some stainless set screws and it worked great as oppose to block dissasembly...

Sleeve mod for inserting with out block disassembly

Sorry for the blurry pics, if you really want to make sure they dont move you can grind them flush and Tig weld them in. I would only use stainless as the original pin was, due to the high temps, and you will need to tap the sleeves first for the set screw.

I had the same question a little while back. I determined that for stock use it is better to have the sleeve in. But I have also realized that there are no major concernes for a NA to run without them other than higher temps in the area of the exposed port thus more heat loss through the cooling system. This could be a problem for constant high RPM and demand of HP such as hill climbing. In Turbo configuration this problem is amplified because of the restricion by the turbo.

Use your best judgment, take a look at my thread "to sleeve or not to sleeve" there are some good arguments there. Good luck...

the old school housings have smaller diameter than most turbo and n/a manifolds so it shouldn't be a problem with sealing with a step.(the whole exhaust port is smaller including the aluminum casting)

i dislike the idea because the exhaust heat is transferred directly to the aluminum rotor housing exhaust port and will vaporize the coolant at the port more readily which may cause added electrolysis. but sometimes you just don't have an easy alternative.

the problem arises when using stock manifolds on later model engines with the sleeves removed which turns the exhaust into a stepped bowl.

just getting back to the rebuilding....took a break and did a bike, a gt mustang, and a tractor... thanks for the replies guys. my biggest problem now though, is the vaccuum lines...all of them...and the little clear oil lines....oh yeah this car is the first rotor motor iv ever seen and or taken apart....

do you have a copy of the FSM?

I didn't see anything mentioned about "old school" so I assumed we were talking about "late model" 86 and up stuff.

Of course, going from a small port to a larger pipe is not too bad. Going from a large port (a stock rotor housing exhaust with a sleeve removed) to a smaller pipe (a stock or aftermarket manifold manufactured to be the same size as the stock housing sleeve) is bad for flow.