Bad treads in an FP30 cast stainless housing

[DAO 1950]

I always wanted and recently purchased an FP3052 turbo. I was told low milage and have no reason to doubt that yet since I haven't run the car. Working on the install I discovered that the threads in the housing to bolt to the exhaust manifold are not the best. I cleaned 2 of the holes up easily with a tap and the other 2 will hold but the threads don't give me a good feeling. Where would I find drill bits and taps with enough strength to put helicoils in that cast stainless housing?

 

[bastarddsm]

Something like that you might be best off taking it to a machine shop. Stainless is tough. Also I/m not sure how a helicoil will hold up on a TH.. Any chance you can just get a nut on the bolt underneath it?

 

[TSiAWD666]

I can tell you it is do-able as I had two bolts seize and snap on me and had a local fabricator repair them with helicoils. They told me it was a pain in the ass though and broke a few drill bits on the process.

edit - realized you don't have broken bolts (per BogusSVO paying attention below) so the broken drill bits concern probably isn't relevant!

 

[BogusSVO]

A decent cobalt drill bit, 135* split point perfered, and either Heli-coil or Recoil kit (Brand Names)
Will do the job.

The kit will be in the $45-$60 price range, the drill bit will be about $12

Since you do not have broken bolts in the holes, and just damaged threads, it will be an easy fix (somewhat)

If taken to a machine shop, I would figure $15-$25 per hole to fix it.

 

[DAO 1950]

I know how difficult that stainless will be to cut, I was afraid of breaking a tap just chasing the threads. Do you think that the tap with the Helicoil kit will survive? Last thing I want is a broken tap in the hole.

 

[BogusSVO]

Those are 2 of the better kits on the market.\

The tap should last a few holes, just inspect it each time, look for the edges flatting. also dip it in oil before you start. It will cut a bit better and you will have smoother threads.

 

[DAO 1950]

Thanks for all the help. Bastarddsm, I don't think there is enough room on the bottom of those holes for a nut, but I will check that when I get home. I did buy some high temp nickel anti-sieze so once I get this issue fiixed it shouldn't come back.