How to repair stripped threads in exh. manifold? (Turbo app.)
How to repair stripped threads in exh. manifold? (Turbo app.)
(OP)
Who has direct experience (successful experience preferred) repairing stripped threads in a cast iron exhaust manifold? This is a very high-heat turbo application so please don't use the word Loctite anywhere near your recommendation. :-]
I want to hear specific experience with Keen-serts vs Helicoil inserts, stainless vs. alloy steel, that kind of input is what I am after.
Thanks in advance!
I want to hear specific experience with Keen-serts vs Helicoil inserts, stainless vs. alloy steel, that kind of input is what I am after.
Thanks in advance!





RE: How to repair stripped threads in exh. manifold? (Turbo app.)
My "post retirement" job of repairing commercial air compressors would have been nearly impossible without Heli-coil. Keep in mind that the "corner auto store" does not carry anything near the complete line of thread repair supplies available from Heli-coil. Google can be your best friend here.
Tried several of the preformed inserts and, since most required some form of locking compound, I found them lacking in stability and longevity, not to mention $$$. Not my first choice.
Rod
RE: How to repair stripped threads in exh. manifold? (Turbo app.)
I foolishly bought a sack of 1/4-28 "Helicoil-Like" inserts on ebay; about every second one broke the tang off as soon as it went into the repair- and this ain't my first rodeo, helicoil-wise. You'd think at my age I would know better.
RE: How to repair stripped threads in exh. manifold? (Turbo app.)
Only if you are a LOT smarter than me...I seem to be the master at repeating my mistakes!!!
Rod
RE: How to repair stripped threads in exh. manifold? (Turbo app.)
RE: How to repair stripped threads in exh. manifold? (Turbo app.)
In short, if you can use a through bolt it will make life easier the next time you have to take the turbo off. I wish all designs were like this.
ISZ
RE: How to repair stripped threads in exh. manifold? (Turbo app.)
Cast iron is not a good material for high temp manifolds as it goes through a phase transition at about 900C. See link below:
http://en.wikipedia.org/wiki/Iron
Use a high silicon ductile cast iron (silicon raises the temperature of the phase transition) or iron-nickel alloy like ni-resist to avoid the phase transition that plays havoc on fastener retention.
Make sure your keen-serts (I prefer keen-serts to helicoils for high temp application, but do not have solid data to back up opinion) are made of a material with a similar CTE characteristic. (Be careful - CTE not constant with temp. I have been bitten by this in a high temp fastener application.)