ok so im at work with nothing to do and my supplies not in front of me. but i just purchased a new lt1 t56 bellhousing and it needs a bolt hole helicoiled because its stripped out. does anyone know off the top of their head the size i need to get? i believe its metric but like i said i dont have the stuff in front of me and i have no experience with helicoils. for example if i used a 15mm socket to get out the bolt, im assuming its a 15mm end that is getting threaded into the bellhousing? and if it is, dont you have to purchase the next size helicoil down from 15? i need some input.

 

Bring the bolt in to the store to find out, theres coarse thread and fine thread in addition to the actual size that needs to be checked. and be sure to go some place other than the zone for your helicoil. Youl'l also be going up a size with the threads not down (and the threads youl'l cut for the helicoil will likely be standard, not metric)

 

i heard they make metric helicoils to match the size you need bc i def dont want to have a random *** standard bolt and all other metric bolts.

 

no you can get a metric or standard depending on what threads are on the bolt.

 

The helicoil has to go into threads, while itl'l provide you with a metric thread for your bolt iirc you usually provide them with standard threads to go into.

 

thanks for the help i figured it out last night, its a 3/8" diameter bolt and im checking the thread pitch tonight

 

bring it to the store if the helicoil packages are openable have one of the guys match it up for you, be carefull though its possible to force the wrong size helicoil to fit because they stretch a bit, it feels different when its being forced vs fitting properly.

 

Im not trying to be a know it all or anything, just going by the text book because im going for tool and die making/cnc programming.. but a helicoil really only holds its strength for one use, and technically is only good for one use. Not saying you cant get by for using the more then once because i think everybody has, but if you want a permanent fix you would want to use a thread insert, and it takes a special tool to do it, but they are permanent and you could probably bum the tool off of a local machine show and order the inserts through them.

 

im not worried about superior strength because im SURE this bellhousing will break along with the past 3 i have had, i just have 1 bolt hole that is stripped by the slave cylinder and need it fixed up. im not ready to dish out 475 bucks on a mcleod sfi bellhousing bc i have heard that lakewood was working on an lt1 bellhousing right now. so we will see what happens.