Turbo Leaks

[K4Eagle]

Thanks to a white smoke cold start this winter, I noticed a leak coming from the exhaust manifold, which led to why the 6v92T was a little slow off the line.  A little welding repair and I'll probably break something else with restored HP.  Wish me luck!

[beltguy]

Welding cast iron is a challenge.  There are several trains of thought as to how to make a satisfactorily/durable weld.  Some folks say that brazing is the only option.  Others have used special arc welding rod.  Yet others have used standard MIG process (mostly for non structural work).

An exhaust manifold complicates the issue even more because of the heat cycles.

Be sure to let us know how the repair was done.

Jim

[davida]

I could hear the thud, thud, thud, of thinness on my street side exhaust bank with hammer taps years ago.  I was fortunate to find a good take off from some truck yard in Brownsville TX and replaced it.  I bet they are hard to find now.  Yes, please let us know how this works out.  Take lots of pictures.  There may be some ideas on you tube that someone has found.

David

[DoubleEagle]

Unless you can find a good used one, take it to a welder that has experience with cast iron. It will need to be cleaned up, preheated, and welded with a nickel alloy rod, and then machined to a flat surface. No guarantees on how long it will last.

[K4Eagle]

Some of you wanted an update.  I think I was lucky getting 55 rod to bond to the cast iron; it was amazing how fast the cast would vaporize, and I'd have to chase the growing pit with rod before it got worse.  Next, I discovered the mounting surface was rounded convexly; probably why the end broke in the first place.  Because of this, I decided to bronze the last port instead of grinding down any of the cast.  Will sand down to spec here soon.

[beltguy]

Thanks for the follow-up. 

I assume when you say 55 rod, you are referring to the special nickel rod such as:

Link to Amazon for Weldcote Nickel Rod

Jim
 

[K4Eagle]

Yes Nickel/Iron rod.  I tried ARC at first but switched over to TIG because I felt I had more control (and it was my first time trying ARC).

[DoubleEagle]

And did you preheat the cast iron to 350 degrees or a little more?

[K4Eagle]

yep.  No pops while cooling.  it was a relatively small area, and there was a good amount of meat to work with.  By contrast, my 78 with a 8v71 had paper-thin manifolds and we ended up having to find a replacement.