Stripped threads

[DedZed]

So I’m a novice gear head...I replaced the oil sump pan gasket and the previous owner(s) stripped several of the bolts holding the pan to the block. The bolts are M6-1. What method would you recommend to repair? I think coil inserts would work and I could keep the original M6 bolts and torque specs. Tang or no tang? Thank you.

240Z 1970 early series.

[grannyknot]

A Helicoil insert will do the job quick and easy, the torque spec I think is  about 6lbs so not a lot, using a Time-sert is a better more permanent fix but will cost a little more.  Using either of those methods means removing the oil pan to do the drilling or drilling through the pan lip and using a larger washer then stock.

[twofouroh]

Only a few of the pan bolt holes in L series blocks are blind, so a helicoil isnt going to work in most of them.  Better just to drill and tap those to 8 or TIG and redrill. . .

[Racer X]

On 1/3/2021 at 10:11 PM, DedZed said:

So I’m a novice gear head...I replaced the oil sump pan gasket and the previous owner(s) stripped several of the bolts holding the pan to the block. The bolts are M6-1. What method would you recommend to repair? I think coil inserts would work and I could keep the original M6 bolts and torque specs. Tang or no tang? Thank you.

240Z 1970 early series.

Helicoils are an excellent method for repairing stripped threads. Be sure and evenly torque the bolts using a torque wrench on reassembly.

What do you mean by tang?

 

On 1/4/2021 at 5:27 AM, grannyknot said:

A Helicoil insert will do the job quick and easy, the torque spec I think is  about 6lbs so not a lot, using a Time-sert is a better more permanent fix but will cost a little more.  Using either of those methods means removing the oil pan to do the drilling or drilling through the pan lip and using a larger washer then stock.

What is a Time-sert? Never heard of it.

45 minutes ago, twofouroh said:

Only a few of the pan bolt holes in L series blocks are blind, so a helicoil isnt going to work in most of them.  Better just to drill and tap those to 8 or TIG and redrill. . .

Why wouldn't a helicoil work in a through hole? I've used them in through holes many times. Loctite red thread locker will keep them in place. 

Edited January 8, 2021 by Racer X

[grannyknot]

33 minutes ago, Racer X said:

What is a Time-sert? Never heard of it.

http://www.timesert.com/

It is a permanent fix, you are actually replacing the threads. It also has a self locking expansion lip at the bottom, very well engineered.  I'm sure there must be some youtube videos of them.  A Helicoil is better than nothing but it's a temporary fix because they are so easy to dislodge.

[Derek]

+1 for Timesert. I use both coil inserts and timeserts. They both have their place. Lots of aluminum parts require coil inserts especially in aircraft work. 

[CanTechZ]

I just came across this video with what seems to be an unbiased comparison of helicoils, timeserts and key locking type inserts. It's very long but shows some interesting results. I won't spoil it for you. Lol

Cheers, Mike

 

Edited December 2, 2021 by CanTechZ