Hello, I've done the required searching but have not found answers.
I am in the middle of a rebuild-89 NA-- because water started getting into the housings-(previouse owner did not change coolant + overheating) the Aluminum has deteriorated about 1/8" into the sealing area of the housing.

My questions are:

Has anyone ever tried to weld up the aluminum and then resurface the housing? The oil was changed and there is pretty much no wear otherwise on this 100k motor.

If the housings are terminal--where is the best/least expensive place to buy new housings?

 

I believe you may be talking about normal seal wear on the chromed compression surface. This usually happens on the rear side of the housing, where the apex corner piece used to ride..it digs that groove, the more mileage, the larger the groove.

Grooved housings are reuseable, but the more groove, the poorer it will run. Breakin takes longer, they flood more, develop less compression, and don't last as long the second time around. I use them all the time with no real problems.

New rotorhousings will run you right around $400-425 just about anywhere. Word has it that rotorhousings are hard to get ahold of right now, along with mazda reman blocks.

 

The Aluminum that has deteriorated on the housing is at the edge of the coolant passage--looks like the coolant never got changed and through the chemical process deteriorated the metal away-the reason the motor failed was the sealing ring gave out from the compression of the motor and the pressure of the coolant system allowed water to leak in.

 

pics

 

YEP, new rotor housings are getting rare- I just bought one from Mazdatrix (they had to wait a week for them to get to the Calif. Mazda parts distribution center), and the other from the local Mazda dealer (they had to get it shipped in- only 3 in the country at the time at Mazda dealerships according to the sales guy)...If you want to get some good mileage out of your rebuild you need to go with new housings- the only noticeable wear on my 186,000 mile engine I noticed during the rebuild were the rotor housings & apex seals, all the side housings have at least another 50,000 miles of wear on 'em before they'll hit the limits...Mine started first crank, idles great, and I can already feel the power coming with only 150 miles on the rebuild...I know it's a cool grand to get 'em new, but it'll be worth it in the long run...

 

they always run out of rebuild parts in the summer. nobody fixes these during the winter so they dont really stock much of this stuff. you'd think they would figure this out....

 

I havent figured out how to attach a pic to the reply so the best I can do is describe it.

I really would like to replace them with new housings instead of used--You cant weld the Aluminum up and then resurface it?

 

And take the chance of warping the entire housing? (although it is trashed to begin with, huh?)...Aluminum's not too fun to weld with anyway, but if you think you can pull it off...Does anybody even know the alloy content of these things? Have you thought about building the area up with some form of epoxy or fastweld?

 

That was another thought ----- somthing like JB weld--Just trying to keep from shelling out 1G for 2 new housings.

I was thinking about talking to some of the welding shops here to see what they thought about it--warping and the actual alloy of the housing are definitely a concern.

 

If you're talking about the actual o-ring ridge wall being corroded away, I don't think there's much you can do about it...I've never heard of that kind of damage being repaired, I have heard of a thin o-ring "wall" being built up to strengthen it, but there was something there to build on...

 

The spot that would have to be welded is about 1/2 the size of a pencil eraser it does not go into the sealing ring area just next to it. I am afraid that if I assemble it as is then it is only a matter of time till it fails. the other housing has more damage but not as deep but on the 2nd one it is into the sealing area

 

Maybe Kevin can help, I know he's seen plenty of used rotor housings, and could say if he'd go with it or not, or if it could be fixed...In any case, even knowing how much they are, I still recommend new rotor housings for any rebuild that's meant to last...

 

Yea after looking at them again and doing some more research. There could be more corrosion I cant see. I think new housings are the way to go--Now all I have to do is FIND some--

Someone sure could make some money if they could find a way to repair housings.

 

There is a thread in the rotary performance section about resurfaced housings, but that applies mainly to the compression surface...not sure what they do for the mating surfaces. The general consensus is that the rotorhousing composition and tooling is largely proprietary. By the time an outside company set themselves up to remanufacture housings,you'd have hundreds of thousands of dollars invested, and it would have been cheaper to just buy new ones from mazda at wholesale.

As for used housings, they normally have some pitting, say 2-3mm at a time. A good sealant (not hylomar) can be used on the mating surfaces during assembly to take care of this pitting, and I never have any problems from it. IF it is not encroaching on the water seal mating surface itself, and you run a proper antifreeze/water ratio from day one, it should never worsen.

 

i agree with kevin and you have to look at rotor housing as a wear item, expensive but true.

 

Thanks for all your help --off to Mazda I go $$$$$$$$$$$$$$$$$