Stripped Engine Case Hole

Hi Folks,

I am in a bit of a pickle. I have stripped an M10 engine case hole, one of the four that attach the transmission to the engine. I ordered a Timesert thread repair kit and went about installing the insert, badly as it turns out, since it does not hold under torque (35FT/LB) and has started pulling out.

What to do now? Try an oversize hole for a 12mm timesert or go with a helicoil if it goes in the existing hole which was drilled out to 13/32.

I had to remove the engine stand bracket to access the hole and found I had to remove the flywheel as well to get a drill close so the logistics of this thing are hell.

Thanks,

J P

You should be able to install an 12 X 1.50 insert, into which you install a 10 X 1.50 insert to get back to original size.

Mag is so soft it's imperative that you don't allow the bit to wander. Heli-Coil is next. After that it's onto the big, ugly head stud insert available for VW cases.

If you have an old trans case lying around use it as a pilot guide. Good luck.

A helicoil uses the same STI tap size as a standard Timesert. The nominal drill size is 10.3mm.

If there is sufficient material I would try an E-Z Lok insert which uses a coarse 9/16-12 thread and has a tap hole size of 31/64"

https://www.ezlok.com/ezlok-insert-650-10

The coarse thread of the insert will be helpful into a soft material.

Thanks for the ideas. I am going to try using the 14mmOD/10mmID case savers found on this site https://www2.cip1.com/SearchResults....rch=case+saver. They have a 2.0mm coarse outside thread to bite into the magnesium and the 25mm length should give max strength.

I will use the half moon engine bracket holding the transmission now as a guide for drilling. Only difficulty I foresee is driving the insert into the hole because the lip of the case interferes with a lock nut on a threaded bolt approach.

TIG welder, magnesium filler rod and a preheat oven. Might want to look for someone that knows what they're doing and be sure to weld in safe place if you go that route.

Big-sert https://www.threadkits.com/big-sert/...-series/50153/

If it were me I'd be inclined get some steel plate to make a fixture and get a mag-drill onto the case. I'm just and amateur and I'm sure the pros who have already chimed in just hand drill it.

andy

Update

It took a while to gather up the parts but this time it worked. I needed a 12mm drill and 14-2.0 tap size but key was getting a proper tap wrench. Gearwrench makes a nice set with a ratcheting wrench but trust them to make you buy a bigger handle for the larger tap. I used a builders square as a guide to line up the whole. The 10mm driver from the time sert kit worked well for the insert. Insert is holding 35 FT/LB without slippage. Hole under repair is on the left.

Attachment 486792Attachment 486793

Had not heard about a mag-drill before. It would have been difficult adapting a fixture in this instance.