Gonna keep it simple, Im rebuilding and porting the motor should I be worried about using this front housing for my rebuild? It has slight pitting/flaking around the edge of the housing in a couple spots.



Also, I read that you can mix-match S5/S6 rotors as long as they are within 25 grams of each other? I'm forced to rebuild due to a foreign object somehow making its way into the rear housing Can you mix-match housings as well?

 

Second picture reveals that housing is trashed. I wouldnt rebuild using that one. Not even for drag racing.

 

aluminum housings are different... not just the port timing and size, but the spark plug placements are different as well.. the port can be ported to match, but there isn't anything you can do about the spark plug timing

do a search on rotor housings and you will see plenty of posts on the topic

 

Oh, sorry that second pic is not the same housing. The first pic is the front housing and the second is the rear one that bit the bullet :/ I know I'm gonna have to buy one housing already, but i want to make sure i don't need to replace the front one as well

 

Let's put it this way, you wouldn't replace one brake rotor and not the other right? Well its pretty much the same concept. Your best bet is going to be bitting the bullet and spending a little extra on two new housings. While it may not be necessary to do it, its always better to have a guaranteed new part than an iffy used one.

 

I'm wondering, though, is that first pic a useable housing? I have four housings in similar condition, but less pitting/flaking than what he has pictured.

 

Imo, i wouldnt use it. You wont ever get it to properly seal at the edges if theyre that pitted. You might be fine though. It's hard to tell not actually seeing the housings in person.

 

hit up goopy performance on that first housing, the 2nd housing though is toast.
http://goopyperformance.com/

I picked up a used housing to replace one of mine and was planing to send them both to them when i get money.

 

If you could pull back from that housing a bit with another picture it will help put the grooves into proper size...

Just from that picture I'd say they are usable. At least according to Mazda's spec. 1/8" of grooving/flaking around the outer edge is acceptable. Depends as well where the flaking is located. Very normal to be found at the bottom of the housing. It's more of a problem if it's in the compression area.

 

if the pitting is at the lower portion of the housing it won't hardly affect compression since it is on the exhaust stroke, if it is located in the upper region of the housings then it is a different story and even marginal grooving will affect compression. luckily this pitting is usually down in the exhaust side and the housing would be reusable with marginal losses. location of the wear is almost more important than the wear itself, but ideally a perfect housing will give best results all around.

S5 and S6 turbo parts are interchangable for rotors and housings, if you use an S6 housing for the rear though you will need to drill out the coolant passage to the lower intake.