T3 turbo has cracked exhaust housing - still useable?

[Feenix]

Mate of mine got a T3 high flowed turbo for quite cheap, however the exhaust housing around the wastegate exit port has 2 hairline cracks. I personally didn't think this was a good thing but the guy who sold it said it was quite common and okay since it wasn't too bad.

My personal thinking is that it'd be ok perhaps for fairly mild applications, but once you start upping the boost it could cause problems.

Any thoughts?

'nix

[OVL087]

as long as they are as u say "hairline" then its still quite useable , if they are any bigger then id suggest getting them fixed ,

[Feenix]

Given you cant weld cast iron how do you fix it? brazing?

[spook]

have seen quite a few cracked housings over the years as long as the cracks are hairline and not opened up its still quite service able but if this bothers you its still worth buying a new ex housing dont bother even trying to repair the cracks as this usually ends in disaster!
hope this was some help......

[Laser]

You can weld cast iron, with cast iron rods.

Brazing might not hold up to the 800+ degrees heat, that turbo engines produce.

[spook]

have you ever welded cast iron before ? in that enviroment i think it would not last very long

[Feenix]

Reasons why you can't (easily) weld cast iron

HERE (http://www.locknstitch.com/ExpansionContraction.htm)

[type_rz]

From my own personal experience, welding cast iron can be done if your careful and the guy knows what he's doing. I had an external wastegate welded to an exhaust manifold a few years ago, and it never showed signs of fatigue or cracking. If you don't believe this, I had to go to the "top" and ask personally CORKY BELL what he though:

In a message dated 98-12-16 04:40:42 EST, you write:<<
1) How would you recomend welding an external wastegate to an exhaust housing without it cracking? (Making a custom manifold is not feasable)
I am told that welding stainless steel to cast iron will cause severe cracking. In reading the book, I see a few systems welded to the housing. Can you help me?


>>Hi Vic,
Thanks for the comments.
Welding iron is subject to the quality of the iron, the material mated to it, the rod used, and the preheat. Exhaust housings are a weldable iron alloy. Mild steel welds nicely to iron. Don't use stainless because the thermal expansion coefficient is twice a great, thus forcing a crack. Use a special rod for welding iron, usually high nickel content. Ask the welding shop what
to use. Preheat the parts to a heavy fuming, or very lightglow. Let them cool as slow as possible.

Corky

This is from my own personal experience, but in your case it could be different (disclaimer!?:p) Hope this helps anyway.
Vic