TR2/3/3A TR3 Oil Pan thread repair

[newmexTR3]

Hey guys,

I have a few stripped threads in my block where the oil pan attaches. It's one of the (many) sources of small leaks, but I'd like to fix it.

How would I repair this? Helicoil?

If so, can you tell me what size helicoil I would have to purchase?

Thanks!

 

[TR3driver]

A Helicoil-type insert is what I would use. (I've been having good luck with Recoil brand; which is generally less expensive than genuine Helicoil.) Those threads are 5/16" NC and most likely the 'medium' length insert would be best.
https://www.allfasteners.com/Recoil-Thread-Repair-Kit-33050-516-18-4010pcs41-403305041_p_2358.html

When installing into a blind hole, be sure not to screw the insert all the way to the bottom. The special tap will leave a few threads not completely cut at the bottom of the hole, which can cause binding if the insert is screwed all the way in. If the insert is too long, you can trim the exposed end with a Dremel & cutoff blade.

 

[newmexTR3]

You're the man. Thanks Randall.

My real fear is that if I successfully stem all oil leaks, I'll be left with under carriage rust-proofing system!

 

[newmexTR3]

5/16" NC

Wouldn't they be BSF?

 

[martx-5]

No Gavin...5/16"-18...

 

[TR3driver]

Nope. All the threads into the engine block are SAE threads, and most if not all are coarse threads. However, some of the studs have coarse threads into the block and fine threads on the exposed end.

The SPC gives the pan bolts at P/N 100749, which TRF has cross-referenced to HU856. Then the standard hardware catalogue gives HU(0)856 as 5/16 UNC.

 

[PeterK]

Not much BSF on the TR3-4s, nearly all is SAE. One exception is the Lucas bits who liked BSF threads.