Re: Heli-coil How-to

["content22207" <brobertson@xxxx>]

Helicoils are the heat, especially in aluminum, especially around
cooling systems. Coil will weld itself to manifold etc, then fastener
will be steel on steel (like it should have been to begin with). Is
truly a one time fix.

Go slow and gentle tapping hole for helicoil. Aluminum is SOFT. You'll
be amazed how little effort is needed. 

Most parts houses stock English sizes only. McMaster Carr sells every
coil made (with FedEx standard shipping): www.mcmaster.com. Their
*ENTIRE* 3,000 page paper catalog is online BTW. While you're there
check out the selection of pipe fittings INCLUDING BRITISH THREAD.
Fastener selection ain't bad either. Only thing they they can't get is
7mm stainless steel (see Fastenal for those).

Oh, you wanted "how-to": 
1) Drill out broken fastener. Isn't end of the world if bit wanders a
LITTLE because helicoil about 1/16" bigger than fastener. 
2) Tap hole for helicoil. English coils are next bolt size up (5/16"
helicoil uses 3/8" thread). Don't know if metrics are same.
3) Screw in helicoil. Is a special tool for this, but I just catch
internal tab with a skinny flat screwdriver. Don't forget to snap tab
off after coil seated (is scored already -- just hit it with
screwdriver). If hole is deeper than your insert simply bottom out one
then follow with another. Can cut coils for 100% fit. 
4) Reattach whatever.

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "cruznmd" <racuti1@xxxx> wrote:
> Ok. I worked on my other valve head until 11:30 last night. I have 
> the timing cover cleaned up, new crank seal installed. Valve cover 
> cleaned up.
> 
> The head went badly. As with the other head, someone long ago, 
> snapped off one exhaust stud. I had to dremel off one bolt. The 
> others snapped off. I did manage to extract all the studs but the old 
> broken off one. One stud welded itself to the exhaust manifold badly. 
> When I pried the manifold off the head, I thought the stud was 
> staying fixed in the block and the manifold was slipping off of it, 
> but what really happened, was the stud remained in the manifold and I 
> ripped the threads out of the head.
> 
> Now I don't care about the manifold. It's toast and I have a like-new 
> set. I want to install a heli-coil in the head because I don't think 
> there's enough metal left to tap it out.
> 
> Anyone know how to do this?
> 
> Rich