I thought that helicore was a temperary fix. Not a way to assemble a 350hp motor. I recently put a stronger set of valve springs on my ZZ4 heads. One of the rocker arm studs broke. So I'm going to send the head to a machine shop to have them fixed.

When I looked at the broken stud I could see a sleeve inside the stud hole. Is this the way they build these motors?

Anyone else have threaded sleeves inside their rocker stud holes?
Are these helicores reliable under race conditions?

Should I scap the heads and get AFR's?

Please help. Thanks.

 

A Heli-Coil is far stronger than any cast metal. I charge people extra to Heli-Coil every single hole in a casting when I build a motor, to prevent problems on down the road. It's especially a good idea in aluminum.

Be grateful that your motor is already upgraded.

 

you have to be carefull when you're taking the bolts out of helicoils though. I'd always take the helicoil out along with the bolt.

 

No, don't do that. The Heli-Coil should basically become a part of the casting. If properly installed, it won't come out accidentally with the bolt.

Just as an example of their usage, my stepfather used to work for Chrysler, a long time ago. He would bring home service manuals sometimes. Well, step 1 in the rebuilding procedure for a 727 transmission (after the teardown, cleanup and inspection procedures) was "Heli-Coil all bolt holes".

 

AFRs are helicoiled too.

 

All of the L98 aluminum heads (which is what you have) come that way.

 

I have contemplated the use of Heli-Coils before. I always thought they were a cheap way out. My bad. The great part of being a human, is that you have the ability to learn everyday!!

 

As RB83L69 mentioned, I would much rather have the helicoils.

Lonnie