Dan,
If the threads are pulled there are a couple of ways to fix this. I will
assume that you want to preserve the piece (F-4B) due to it's historical
Value. If not.....pick me as I will take.
Remove Intake Method:
The best way is to remove the intake and re-weld the hole up with a tig
welder after cleaning well with engine degreaser and then dousing several
times with brake clean and blowing dry to remove as much of the fuel and oil
contaminants as possible to attempt a clean weld. Then just re-tap the hole.
Good luck with this one as the original castings were very porous and may be
too contaminated to weld nicely.
Do Not Remove Intake Method:
Another choice is to purchase a thread-saver kit like a Helicoil Kit. The
kit comes with the required drill bit, the required tap and the correct
Helicoil insert to repair the threads. If you are reasonably athletic you
will probably be able to do this in the car but be sure to tape up the
opening into the plenum to ensure that NO aluminium gets down into the
intake. The trick hear is that when you drill out the hole for the stud be
sure to have the drill perpendicular and go slow. Once the hole is enlarged
then tap it with the bottoming tap provided and then screw in the Helicoil
with red locktite using the tool provided. Once repaired the thread surface
becomes stainless steel and is very durable. In Fact, on the early aluminium
heads on some of my old GM powered racecars (sorry for the non-tiger stuff
comment) we would helicoil all of the intake and exhaust thread bosses to
ensure that they did not fail after repeated Re & Re of intakes and headers.
The kits used to be pretty pricey at about $50 Can but it came with several
Helicoils and you could then buy extra inserts. My buddies and I used to buy
different sizes so that we had the ability to share the drills and taps and
just bought the inserts in bulk.
I hope that helps,
Tim Ronak
PS: If you decide to go to the Performer RPM, I do believe it works a little
better than the F-4B and is a better casting. Let me know about the Damaged
F-4B as I might like to acquire it.
|