Spark Plug Stripped, Repair Stripped

[Ando81]

Hi all , I’m wondering if someone can help me with a Stihl 029 which has a stripped spark plug thread. It has had a dodgy repair done with a threaded sleeve put into the head and on the weekend I managed to strip the insert out of the head. My question is, am I able to put a bigger insert properly into the head and a helicoil inside of it to get me back to 14mm spark plug thread. It’ll basically have 2 thread repairs together, not ideal but basically my only option to get this old girl going again. I’d greatly appreciate any help. Thanks in advance, Justin

 

[buxfan1911]

A top end rebuild kit is only $50. Probably cheaper if you only buy a new cylinder.

 

[Derf]

The easiest solution would be to replace the cylinder.

The proper “fix” would be to find a machine shop that also does welding, have them weld the hole up and re-machine it.

The jury-rigged attempt is what you’re considering.

 

[Van462]

Google keensert and see if that fits your need.

 

[HarleyT]

Put up pics of what you have left. There are some repair inserts that are bigger than the others.

 

[Ando81]

Thanks for the input, I’ve used keysert inserts into aluminium for stripped rocker cover bolts with great success. I understand that changing the cylinder would be best but I was thinking that a genuine Stihl cylinder would be better quality than aftermarket. The machine shop idea sounds good, I’ll get some pics soon to decide it’s fate.

 

[lone wolf]

Thanks for the input, I’ve used keysert inserts into aluminium for stripped rocker cover bolts with great success. I understand that changing the cylinder would be best but I was thinking that a genuine Stihl cylinder would be better quality than aftermarket. The machine shop idea sounds good, I’ll get some pics soon to decide it’s fate.

It may come down to price check the Machine shop price Versus new Cyl.

 

[mike-s]

Was someone using a breaker bar to install plugs?

 

[lone wolf]

Was someone using a breaker bar to install plugs?

1/2 impact gun.

 

[Huskybill]

Oh no impact gun. I seen 18” 1/2” dr wratchet used on tranny drain plugs, the wrong direction, righty tightly, lefty loosely. I welded up the stripped hole and redrilled it for the kid.

 

[lone wolf]

Oh no impact gun. I seen 18” 1/2” dr wratchet used on tranny drain plugs, the wrong direction, righty tightly, lefty loosely. I welded up the stripped hole and redrilled it for the kid.

Cross threading is also a possibility.

 

[Ando81]

I’ve only pinched it up firm with a Stihl spark plug tool. When I looked closely at the spark plug I noticed that it looked crooked in the cylinder. Maybe the insert had been installed and cross threaded from the beginning.

 

[L34]

Last 2 I done was keen serts.
All good so far.

 

[Ando81]

I’ve taken a couple of photos of the damaged thread. I’m assuming that it’s been drilled too big and tapped to 16x1.25 and the insert may not have gripped on much thread. I’m hoping a keysert insert will have more precise threads that can grab onto the alloy cylinder. I also found that it’s a Ms310 cylinder, Genuine Stihl.

 

[L34]

I think the keen Serts I used was approx 18mm od thread.

 

[Yukon Stihl]

I saw a repair done by rocketnorton...
He took a bigger plug cut it off and tapped it for the small plug.Tapped the cylinder for the big plug and locktited it in.
Seeing it's a 029 that is what i would try if the hole is to big for any repair kits

 

[HarleyT]

I’ve taken a couple of photos of the damaged thread. I’m assuming that it’s been drilled too big and tapped to 16x1.25 and the insert may not have gripped on much thread. I’m hoping a keysert insert will have more precise threads that can grab onto the alloy cylinder. I also found that it’s a Ms310 cylinder, Genuine Stihl.

Wow! Get another cylinder!! Turn it into a ms390!!

 

[rupedoggy]

I seen 18” 1/2” dr wratchet

This must be a tool from Elmer Fudd's tool box

 

[Ando81]

Wow! Get another cylinder!! Turn it into a ms390!!

I was wondering this, if I’m going to the trouble of getting this cylinder off should I put a bigger piston and cylinder on it. Would it fit up to the bottom end the same?

 

[Okie]

I seen 18” 1/2” dr wratchet

This must be a tool from Elmer Fudd's tool box

The 18 inch breaker bar is what Wal-mart Bubbas use to install the oil filters and drain plugs in your vec after they have changed the oil and put in the WRONG OIL after a 3 hour wait for them to get er dun.
I've noticed these guys usually have 1/2 of their head shaved, lots of tatoos, and big ear and nose rings. Must be part of the job qualifications.

I'm now back to doing my own oil changes after having to repair stripped oil pan drain plugs and having to chisel off the oil filter ring.
Can you imagine having them Bubbas to these repairs that they screwed up in the first place????