[jwwiff]

I have a 318 and the ground bolt on the head is stripped out. Can the hole be re-drilled and tapped or will that damage the head? Are there other ways to secure the grounding bolt?

 

[jim_d]

You can ground that any place on the engine. It doesn't need to be that particular bolt.

 

[whstubb]

If you insist to use this bolt for your ground, might want to look into a Heli Coil kit from your local hardware store. However Jim is correct, can use most anyplace on the engine for your ground.

 

[Hammerdown-7]

Hello James
There is enough meat in that head boss where the negative battery ground wire attaches to drill it out to the next bolt size being a 3/8 bolt hole and tap it for threads. I would suggest that you get a number drill for that job that matches the taping size to use a 3/8 fine thread bolt in i
place of the 5/16" bolt that is stripped. Just be sure to drill the new hole straight and you won't have any issues and I would stick a smaller drill Bit in the hole all ready there and mark the bit to the depth that it is. Then Take some masking Tape and wrap around the number drill that you will use to drill out the hole to the next larger size, that way you will not go too far into the head Boss when drilling the new hole in it. I hope this helps, Kurt

 

[dr_evil]

JAMES,KURT - Fine threads into a diecast cylinder head are a really BAD idea. Fine threads into any non-ferrous metal is not recommended. Always use course threads into aluminum or diecast metal.

 

[deaddeere420]

I would have used a heli-coil and been done with it
They work so well I keep several kits in my tool box for various sizes.

 

[wmgeorge]

Frankly... I would just put a slightly longer bolt in the hole, use a washer to adjust if its too long. The new longer bolt will cut enough of the thread in the soft aluminum to work. Done a few times so I know It will work.

 

[jwwiff]

Guys - thanks for all the great advice! I'm more of a sponge on this site and have learned a lot from the more seasoned veterans.

 

[hankvc]

In that location, I'd heli-coil the hole. Reason being that it's where the lifting ring attaches, and you don't want that to come loose when you hoist the engine. Also, use the longest cap screw that won't bottom out in the hole with the stack-up of the lift ring and the ground strap.

A quick fix for a 5/16 UNC hole that is stripped out is to tap it for an M8 metric cap screw, which is about .005 inch larger. Not really a proper fix, particularly with the lifting ring to consider.

Hank