On Apr 25, 7:44*pm, Wayne wrote:

It's supposed to be a pain to get the turbocharger out.
But if it was out, I could finish the hole with a
7/16 HSS end mill. That I think, would give me a more
round hole than drilling by hand under the hood.
So I would think it would seal better that way.


Wayne D.

No need to have the hole perfect. Also no great worries about tapping
hot and having the hole/threads change size when cool.

Why not? It's a tapered pipe thread. If 7/16" is the right drill
for that thread (and I don't have a chart handy), the large end of the
taper will be cut to greater than that. As to the hot vs. cool size,
just let the cast iron cool down before you install the part. It
won't thread in as deeply as it would have into a hot casting, but
that's all. If that's a problem, thread it deeper cold.

John Martin