I have TF aluminum heads and need to repair 3 holes. Whats the best way.? If heli coil is the right way, how does that work. Never did one. Thanks

 

A "kit" is available for the size of bolt you want to screw into the repaired hole. It will include a special tap that has the right pitch threads (normal taps won't have the right pitch for the size), the helicoils themselves, and the tool for inserting the coil.

The hole is drilled to the proper size, tapped, and the coil screwed in with the tool. The tool is removed, and you've got new, stronger threads.

The kit will cost you about what a shop would charge to fix 3 holes (depending upon accessibility to the holes).

 

Should I have them fix it or do it myself? Its the 2 center ones on the driver side head and the 2nd on ont the driver side head as well.

 

The chances of getting them right is greatly increased if an experienced shop does them.

Heads on or off right now?

 

they will be off

 

matt:

to add to what tim said.. the helicoil kits should be in stock at any major auto parts store... i carry a couple different sizes in stock at work, and can order other sizes if need be. this is presuming you decide to do that yourself once we get the motor pulled.

with the heads off, shouldn't be very expensive to have those holes repaired.

 

Not hard at all to install heli-coils, just remember to use a good sharp bit (a reem would be better but harder to get) . Get the bit straight and centered in the hole (ues a 1/2" drill) and go slowly, let the bit do the work, you shouldn't have to push the drill much at all. Then follow the directions on the kit, using lots of oil on the tap and backing it out often to clean the chips off.
Be sure to clean the head throughly, you don't want those chips down in your engine.

BTW, you want the 3/8-16 kit, it usually comes with enough heli-coils to do all of the manifold holes on a pair of heads.

If you are going to have a shop do it, have them do all of the bolt holes, you'll be happy for the extra insurance. Or do them all yourself if the first few go good and you're feeling confident.

 

there are many, well several, kinds of thread inserts. helicoil is about the last one i'd use. only good thing about helicoil is they seem to require less space than most others, but require "special tools". there are some inserts that just use a bigger size tap and lock in place. look in the yellow pages for a store that specializes in fasteners and see what they have. i'd do all the holes if i'm doing one, sooner or later you'll need it.

 

The only "special tools" you need are provided in the kit, the tap and install tool. Also, they are the only thread repair method approved by the FAA. I wouldn't use anything else.

 

I used Re-Coil, an australian company (similar to Heli-Coil). This company has dealer in USA too (I think). The good deal with Re-Coil is that my local dealer RENT the tools for 3 days (too cheap). I bought the coil, installed it with good tools, and ready. No more money for this repair.


Denis V.