Can you fix this

[Big_Wood]

Oh, there's plenty of meat there. I saved an 066 jug once that had two failed spark plug thread repair attempts. I drilled it out and tapped 18mm threads and used a small block Chevy spark plug in it.

how did you make the taper J.J? that's an awesome redneck repair . if i were WDO i would just chase the threads then thread the correct length heli-coil in there now with a bit of loctite. guy who originally did the repair probably didn't use loctite so the heli-coil backed out when he removed the plug.

 

[Big_Wood]

i used a heli-coil in my very first 3120 back in 2007 and the thing is still holding like new. i have since swapped that top end onto my regular use mill saw.

 

[Little Al]

I, ll try to get a better pic. It looks like it's a repair. The helical is very short
Not even the same length as the plug. It really needs an solid insert....not a helicoil. I go ogled and found big-sert. Not sure is something like that is needed or if a reg. Insert will work.

If you can source a Timesert kit i think you could fix it. IIRC the timesert is larger OD than helicoils & is a solid sleeve with a lip on the outer end. For a really bad one I have tapped out to 18mm(old spark plug size) & used an 18 to 14mm reducer

 

[NathanA]

how did you make the taper J.J? that's an awesome redneck repair . if i were WDO i would just chase the threads then thread the correct length heli-coil in there now with a bit of loctite. guy who originally did the repair probably didn't use loctite so the heli-coil backed out when he removed the plug

Definitely worth a try just don't the put the spark plug in until the Loctite has set might stick the plug to the heli coil

 

[whitedogone]

If you can source a Timesert kit i think you could fix it. IIRC the timesert is larger OD than helicoils & is a solid sleeve with a lip on the outer end. For a really bad one I have tapped out to 18mm(old spark plug size) & used an 18 to 14mm reducer

It looks like the timeset kit would be over run about $300. It looks like a great way to repair it. But not at that cost.
http://www.timesert.com/html/bigsert_sparkplug.html







.

 

[whitedogone]

I need M14-1.25, right?

 

[NewToStihl]

Helicoils were common from the factory on older cylinders.
I bet that's an OEM helicoil and someone cross threaded a plug into it.
Can you blow the pic up a little more, I'm having trouble seeing it.....

No kidding? That's really interesting. I've seen a couple of older Stihl saws with helicoil type repairs that were done so well it took a second look just to realize it was repaired. Makes me wonder if they came from the factory like that...

 

[Jacob J.]

No kidding? That's really interesting. I've seen a couple of older Stihl saws with helicoil type repairs that were done so well it took a second look just to realize it was repaired. Makes me wonder if they came from the factory like that...

Many came from the factory with Heli-coils already installed. Scarr pointed out that a properly done Helicoil is actually stronger than base threads cut into the same material. One example is the exhaust mounts on early 385 cylinders- they came from the factory with Helicoils.

Of course there's a population of people who've already convinced themselves that all Helicoils are bad...

 

[67L36Driver]

I have several old mag. saws with helicoils factory installed. In particular, Remington exhaust port bolt holes.

 

[brian.b]

the one i did was a 460 magnum ,,,i was afraid it would hit the side of the jug but it had plenty of room.

 

[whitedogone]

Well, local auto stores have them kits for like 30$. I've been on the road this week and go right by the main head quarters for jc whitney. They have a retail counter there so I thought I'd check there. They had the save a coil kit for like 26$ and a no name kit for 17$. They had one no name kit all taped up without packaging they sold me for 9$. OK, I'M a tight a$$. The inserts with this have a shoulder that gives the plug washer something to seat on. I'm thinking of using red locktite on it. What do you think?

 

[mweba]

You don't want an insert that seats again the washer.

 

[edisto]

Of course there's a population of people who've already convinced themselves that all Helicoils are bad...

They must not be as ham-fisted as the rest of us.