62 Bellhousing Thread Repair - Insert?

[bhap]

I have a 60-62 hydraulic clutch bellhousing with the rear engine mounts I'm planning on using in my 62 C10 when I swap engines to an L31 crate. While cleaning it up, I noticed that the two rear mounting holes are "loose" when I thread a 1/2-13 bolt into the housing. I'm trying to decide if I should use a helicoil, EZ Lok or something else to repair the threads? My experience with helicoils has been hit and miss, and I have not used an EZ Lok. EZ Lok's have a pressure activated coating on the outside that is supposed to hold the insert from coming loose. They use standard taps on the outside so install will be a little cheaper. Any suggestions on which is going to be stronger? And "while I'm at it", has anyone threaded the two lower holes for the transmission to mount to? The two lower holes are not threaded so I'll have to use nuts inside the bellhousing. The bellhousing is cast iron.

Thanks for your help.

[mongocanfly]

We use a variety of thread repairs where I work... most common is helicoil...but not the best..
We also use key lock inserts..but they require a special tool to install
For your purpose the ezlock would be best option...
just make sure you have enough surrounding metal to keep from breaking out...

[64shortbox]

Here's what I use from McMaster-Carr

https://www.mcmaster.com/threaded-in...cking-inserts/

[bhap]

Yes, I was looking at those, just wondering if the sealant will hold them in place under the strain of the motor mount. I was also looking at Time-serts - a little pricey for their kit, but looks like a good option too.

[64shortbox]

I've used the threaded inserts with the thread locker on them many times without incident. I used one on the bellhousing for the clutch pivot ball on the company dump truck about 7 years ago and it's held up fine & that truck gets beat on. The only thing I would do is after tapping your hole for the threaded insert is to blow out the hoe with some Brake Clean and let it dry completely before installing the threaded insert.

[Jeffh]

Not sure how loose the bolts are but myself I would just red locktite them and if you can torque them to the right spec I would call it good.

If you have the correct transmission the lower mounts are threaded and you put a bolt in from the flywheel side threaded into the transmission. You can't thread the bellhousing as the holes would be too big to thread to the correct size.

[vince1]

https://www.natool.com/wp-content/up...atp113-116.pdf

Sometimes I'll go next size up metric. It might not work in this case.

I've had good luck with Heli-coil too but the tools are expensive if not already in your possession. Loctite or form a thread?

[bhap]

Thanks for the replies everybody, I think I'm going to use the Time-sert inserts. The current threads are pretty worn and the last thing I want to do is pull the engine back out to put an insert in after I try to tighten the bolts and the threads let go. The main reason I'm going to try the Time-sert is that the .65" insert is almost exactly the same depth as the old thread and the time-sert "locks" into the hole when the last few threads are expanded by the insertion tool (apparently you can also use red loctite as insurance). Since this is the rear engine mount and also serves to hold the transmission, I'm going to go with what I think is the strongest - I'll let you know how it turns out - thanks again.

Bob