supraturbo1987

iTrader: (4)

Well, got the motor out and stripped down fully today. Popped open the front casing to reveal the front rotor and housing (the one that had 90-35-35psi pattern) Around the leading spark plug, there is a nice grooved trail about 2 inches in length from the bottom of the spark plug hole going down. Also, a nice deep groove right in the housing inner surface as well right at the exiting exhaust about 2 inches in length. I didn't notice however that any apex or corner seals were cracked...but i didn't look really hard either. SO...I need a new housing. Rotor seems to be in good shape. I don't like the idea of using a used housing either. Got to get all my parts together now and get moving.

Trev

RotaryResurrection

iTrader: (8)

IF the rotorhousing has a gouge, you have to ask yourself why it is there. Examine your apex seals, especially at the tip of the long top piece, and you'll no doubt find a fragment missing there. That is a detonation/force break of the seal at it's weakest point. Even a brand new seal can be broken at that point.

I'd go with a used replacement if your other one shows much wear at all. I dont like the idea of one new and one used housing, though it will work. You want your housings to match as closely as possible in terms of wear and flatness.

supraturbo1987

iTrader: (4)

Thanks for the tip!

Trev

supraturbo1987

iTrader: (4)

So I buy my 93 from forum member and it turned out to have a blown front rotor. Okay, I have done teardown and need a new front housing. Problem is that the motor was rebuild 25k ago and they did a mild port job....so i gotta match the porting...i guess that isn't a big deal...but do i keep my rear housing and get a new front one or just get a used front one? my front one now has 2 nice grooves in it, and it trash. rotor seems good though. Any opinions. I have heard it isn't a good idea to mix one used and one new housing, although i don't understand that rationale completely.

Trev

RotaryResurrection

iTrader: (8)

You'd obviously need to port match any replacement housing you buy. Don't try and buy one already ported or pay someone to do it, because the port must match the other one exactly...you need to first make a template from the other port, and then transfer that onto your replacement housing.

Almost all used housings have some wear. That is, light grooving and uneven surface. IF the engine was rebuilt *with new housings* 25k ago, then the rear housing might still be like-new. IF it was rebuilt *with used housings* 25k ago, then the rear probably has about 75-100k total use on it.

Older housings with wear don't seal as well, even with new apex seals sliding against them. A used housing will generally make 110-115psi compression once broken in, less to begin with. New housings are obviously perfectly flat, and will seal better both initially and after breakin. So if you had a worn rear housing and a new front one, you'd have uneven compression in the chambers...maybe 125 front and 110 rear. That makes for uneven idle and response. It will still run okay and all, but you want them to match as closely as possible for this reason.

http://www.rotaryresurrection.com/3r...ear_guide.html

supraturbo1987

iTrader: (4)

He did replace the housings 25k ago. I will check on the wear of that housing then to determine whether to go with a slightly used or just bite the bullet and go with a new one. I am tempted to drop the money and go for 2 new ones.

Trev