I did a search on this and found nothing so here goes... I have a 13B engine that I took apart, everything is pretty much within spec except for one apex seal and spring. The rotor housings are in good shape (no chrome flaking) and also within spec, except that one of them has a small rust hole that ate between one of the coolant passages and the inner rubber seal, right in the spark plug area. I was wondering if it can be welded? Anyone try this before? Or am I better off buying two new rotor housings (I know they're expensive, but how much are they really)?

 

well it can't be rust since the rotor housings are aluminum. some pics would be helpful but shouldn't be a problem if it's only in the coolant passage.

 

You could try grinding out any remaining corrosion, having someone TIG in some material, then grinding it flush again... but we're talking iffy here.

Is it worth the risk of possibly having to re-tear down the engine and replace the housing anyway, if it doesn't work? That is something you'll have to figure out.

I'd probably go for it, but I am rather cheap like that, and I have access to a TIG and someone who knows how to use it.

 

Make sure the area is REALLY REALLY REALLY clean, any contamination of the weld area and you are asking for trouble. No oil, gas, gunk or anything, just clean virgin metal. If done right there should be no problem.

 

Thanks for the info, I'll probably try this right after I find out how much those housings cost brand new. Yea I'm cheap, and I also think that if it's done right it should last quite a while. I tried taking pics, but the area that's eaten is so small, and the metal so shiny that you can't see it in the pics. Wife is acting up once again and says the 7 costs too much to fix so I've got to try this. I'll try taking some other pics and post them.

 

You didn't say which 13B you had, but Mazdatrix's current prices (USD) are:

'84-85: $405.92 (will work in all '74-85 13B)
'86-88 except below: $496.34
'86-88 Turbo rear housing: $458.46
'89-91 except below: $492.11
'89-91 Turbo front housing: $496.34
FD front: $580.49
FD rear: $575.52

RX-8 (for what it's worth): $491.09

I strongly recommend the RX-8 rotor housings. Combined with '74-85 side housings, you will have no exhaust ports at all. Zero emissions vehicle! The trees and glowy glistening-eyed bunnies will love you.

 

If you compete in any motorsports with the RX-7, you qualify for www.mazdamotorsports.com discounts. A 13B rotorhousing through them is $307, a substantial savings.

 

It's from an 84 SE. Peejay, I'm guessing those prices are in US $, which makes those housings pretty expensive! I'll probably try the welding, even if I totally ruin the engine, I still have a spare one to rebuild (the one that's in the car now burning a small amount of coolant). I might try those RX8 housings one day...