I'm hoping to get some good ideas on how I should go about fixing one of the helicoils in my head that wont hold the correct torque when I tighten down the intake. I've though of increasing the bolt/helicoil size or maybe using some jbweld and a new helicoil? what are my options? what would you do?

 

Just put in a new one.

 

I tried that last time I had the intake off.. still wouldn't hold full torque

 

Try some locktite.

 

It sounds like the Helicoil tapped hole is oversize, or there is too much of the aluminum stripped out. You could go to the next larger standard thread size, but you might have to open up the hole in the manifold. I don't remember if the bolts ar 5/16 or 3/8. If they are 3/8 you could go to 10mm (about .015 in. larger), and put in a 10 mm Helicoil. You'd have one bastard bolt, but it wouldn't be much out of place.

Another option is a key-locking threaded insert. Try looking up this item in McMaster-Carr catalog: 93340A420

http://www.mcmaster.com/

This might be your best bet. Look back one page for the description.

Welding up the hole and remachining it is a real chore.

I'd stay away form the jbweld, etc.

 

Going to a 10 mm thread (X 1.5) from a 3/8" X 16 tpi. would probably accomplish the dilemna of the O.D. slop in the hole (the extra 64th could do wonders) but a small amount of thread shaving, on one side of the thread (cross threading), caused from going to the 16.9 tpi. from the 16 tpi., would be experienced in addition to the 'major dia.' increase, but minor, and that option very workable, nonetheless. I agree, it's a good idea. How 'bout locking in a stud, in that location, as an option?

 

Look at this part # on mcmasters web site.
90240A003
I have used these with great resluts on holes that the helicoil threads have been pulled, leaving an over size hole.

 

90240A003 looks interesting.. but damn $113 for the driver tool?! I found another key locking insert that has a 3/8-16 with a 9/16-12 external dia size.. what should I get? any way around that driver tool?