Heli-coiled MS 460

[GoRving]

I recently got a decent-looking 460 at a good price due to low compression issues. It ran ok, but I later discovered a poorly-done heli-coil job. A Stihl mechanic says that he has some aircraft-grade coils that work well most of the time. OEM cylinders and pistons are so expensive, but I want to get it fixed "right". Open for suggestions on good after-market parts, or ideas about a good heli-coil job. Thanks!

 

[lone wolf]

I recently got a decent-looking 460 at a good price due to low compression issues. It ran ok, but I later discovered a poorly-done heli-coil job. A Stihl mechanic says that he has some aircraft-grade coils that work well most of the time. OEM cylinders and pistons are so expensive, but I want to get it fixed "right". Open for suggestions on good after-market parts, or ideas about a good heli-coil job. Thanks!

What the Cyl mounting bolt holes are stripped or what?

 

[Big_Wood]

low compression so i'm gonna assume it's the plug threads. all you really need is a standard heli coil and do it right. i loctite the heli coil in and they do not come out after that. i never had a problem after a repair.

 

[GoRving]

What the Cyl mounting bolt holes are stripped or what?

spark plug.

 

[GoRving]

low compression so i'm gonna assume it's the plug threads. all you really need is a standard heli coil and do it right. i loctite the heli coil in and they do not come out after that. i never had a problem after a repair.

10-4 on that...Thanks! I'll let the Stihl guy try that first.

 

[GoRving]

The heli-coil that's in it is loose. If I could remove it, I would loc-tite it and put it back, but I'm not sure how easy it would be to remove the old one. It has some "shake" to it. How is the best way to remove?

 

[Big_Wood]

to remove it you grab one end and pull. you will need a new one to reinstall. let loctite cure overnight before you thread a plug in it.

 

[GoRving]

to remove it you grab one end and pull. you will need a new one to reinstall. let loctite cure overnight before you thread a plug in it.

Thanks!!

 

[lone wolf]

Let some one do it that has done lots of them before you go screwing with it.

 

[Big_Wood]

Let some one do it that has done lots of them before you go screwing with it.

if the hole is already tapped it's gonna be real hard for him to make it any worse

 

[paccity]

had a 200t that had a loose save a thread in it and i sweated in some silver solder and restaked it . still works with lots of hr's on it.

 

[GoRving]

Thanks for the replies! As I mentioned, I am going to let the local Stihl guy fix it. He's had good luck doing them. If all else fails, he will put a new p/c on it. Too nice of a saw not to fix.

 

[heyduke]

though i've never used one for a spark plug, i've found time-serts to be superior to helicoil. also if your helicoil is loose, you're not likely to succeed with locktite. check madsen's for time-serts.

 

[Mo. Jim]

though i've never used one for a spark plug, i've found time-serts to be superior to helicoil. also if your helicoil is loose, you're not likely to succeed with locktite. check madsen's for time-serts.

I have the time-sert spark plug kit and they make a permament repair and don't come loose like a helicoil can. Kit is pricey, but the kit will pay for itself if you use it a few times.

 

[banditt007]

DONT GRAB ONE END AND PULL thats a way that you have a huge chance of messing up the threads, especially b/c they are aluminum. What you need to do is take a look at this

this is the official tool to uninstall them, make one yourself, you place it squarely in, and lightly tap the top, while keeping downward pressure you simply unscrew the helicoil. make sure you are 90 degrees away from where the top of the helicoil is. While pulling it out may work, the risk of screwing up the threads is definitely there. Also if the hole is too messed up for a helicoil, you can look into the keen-serts or time-serts. These are basically steel threaded bushings, where the OD is threaded, and the ID is threaded to your spark plug size. you need to remove more material than a helicoil, or you can actually double up helicoils. good luck let us know how it turns out, o yeah, if at all possible make yourself a drill/tap guide to go in squarely and do it on a machine. even if you only have a drill press you can clamp the cylinder up and put the tap in the chuck, and grab the chuck by hand back n fourth to tap it. this allows you the feel but keeps you square. don't forget lots of cutting lube

 

[Big_Wood]

heli coils pull out real easy. i never has threads bugger up even in magnesium. i don't try pull them out after loctite though. there permanant after that. that nifty tool won't even get them out.

 

[paccity]

save a thread is heli coil same as time serts. not the coils like norm heli coils. just make sure you stake them in good so they don't come loose.

 

[GoRving]

Thanks for the replies!

 

[MS460WOODCHUCK]

If you are going to have your dealer do it then just let him do it would be my best suggestion.

 

[fastLeo151]

save a thread is heli coil same as time serts. not the coils like norm heli coils. just make sure you stake them in good so they don't come loose.

Save a thread is the only option in my opinion. I have not had one fail yet