stripped spark plug threads

[mofish75]

any ideas on how to go about fixing the threads where spark plug goes into cyl.
ms660

 

[gunnusmc03]

Helicoil will do it.

 

[smokey7]

They make chaser/taps if someone cross threaded it. It only works if there is metal still available to hold a thread.

 

[Franny K]

They should have some choices at a good auto parts store. A kit that has an insert and a ream/tap thing to get the hole ready for the insert. I suppose one kit is a genuine heli coil kit. I did a lawn mower a couple of years ago and hooked a shop vac in the blow mode to something probably the exhaust to blow out the chips as the ream tap was used. Likely the best results would be removing the cylinder and mounting it in a vice on a machine, vertical mill, jig bore or similar to do the hole clean up/ thread cutting for whatever insert is used.

What size plug does a MS660 use 10, 12, or 14mm are the sizes I come across.

 

[1Alpha1]

A little off topic, but not much.

For as long as I can remember, I've always used anti-seize compound on the threads of spark plugs, as well as cylinder head nuts and cylinder studs. I can't recall the last time I had stripped or corroded threads to deal with.

And, I never use a torque wrench when it comes to tightening spark plugs. I just use a plug wrench and my garage tested / dyno-tuned hands.

 

[pioneerguy600]

I have used Timecerts on a dozen plus cylinders now, works like a charm. Helicoils will work great if the hole is not over sized and the Helicoil job is done properly, for first timers it would be beneficial to read up on installing them first.

 

[a. palmer jr.]

I had an old Volkswagen years ago with a stripped plug hole and got a kit from NAPA to insert a threaded bushing in the hole. It worked until I got rid of the car which was a long time..

 

[Deleted member 135597]

And, I never use a torque wrench when it comes to tightening spark plugs. I just use a plug wrench and my garage tested / dyno-tuned hands.

It's called a calibrated elbow and yes I have one too

 

[AKDoug]

Helicoil Sav-A-Thread work like a charm. I highly recommend removing the cylinder to do the job.

 

[1Alpha1]

It's called a calibrated elbow and yes I have one too

Yup.....works like a charm!

BTW......I liked you in Cheers.

 

[mofish75]

yeah,bought saw from member couple months ago&failed to notice few things.ie,plug hole until spark plug popped out while getting n some wood.really didnt feel cross threaded,so put back n&kept on chopp'n on some tree.then happened again&with better attention being paid,notice there were nearly any threads at all.so here we are,30+"tree fresh on ground&mr.Miaggi MIA&only 14"saw running(which have2say,is a BadAzz14).xtra hp&10" would b nice rt bout yesterday(thats what she said,i know)

 

[Big_Wood]

A little off topic, but not much.

For as long as I can remember, I've always used anti-seize compound on the threads of spark plugs, as well as cylinder head nuts and cylinder studs. I can't recall the last time I had stripped or corroded threads to deal with.

And, I never use a torque wrench when it comes to tightening spark plugs. I just use a plug wrench and my garage tested / dyno-tuned hands.

i would call anyone who used anti seize on a saw a brain dead hooligan especially on plug threads LOL only place i ever use anti seize for plug threads is on some of the aluminum head toyota's and some marine engine head bolts but very very rare. of course, dano here has never worked on a saw so he's just talking out his ass again.

 

[Greg Perryman]

I agree on the helicoil idea. Had it done to my 441 so far it's been good now for 3yrs.

 

[drf255]

Another vote for helicoil.

Just make sure you tap squarely. And but the helicoil branded tool and inserts.

Like made at a better factory in CHINA.

 

[smokey7]

The thing i dont care for with helicoils in this app is trimming the drive tail off. I have seen them left long hanging into the combustion chamber.

 

[drf255]

The thing i dont care for with helicoils in this app is trimming the drive tail off. I have seen them left long hanging into the combustion chamber.

They make a short insert that fits perfectly. I did an 044 head with one and you can't tell at all. No cutting required.

 

[smokey7]

For sure they do make all different lengths and sizes. If its too long just gotta trim it. Just something to look out for.

 

[srcarr52]

Use the threaded insert style repairs for spark plugs, the regular wire coil removes too much of the sealing surface for the spark plug and thus the spark plug will not seal well. These inserts come by many names and one of them should be available at your local auto parts store.

Example names:
Heli-Coil Save-A-Thread
Fix-A-Thread Plug-Saver

The best insert repair available is a Time-Sert specifically for spark plug threads, but those kits run $160 without inserts.

If you can't get an insert to work I have welded, drilled and tapped a new threads many chainsaw cylinders.

 

[HusqyStihl]

***TIMESERT OR CALVAN INSERTS***!!!! Not HeliCoil!! Not against HeliCoil, just not a fan of them in compression applications... Why chance it, read below before hating me....


Go with TimeSerts as mentioned!! The problem with helicoils is that the compression cango through. TimeSert makes any size, comes with reamer, chaser, and a couple size inserts of your choice. Calvan is even better in my opinion, that insert you drill a second hole where a permanent pin slides through the insert and into the jug so the insert never rotates back out with the plug (be sure to correct the size of this pin as to not obstruct the cylinder).

You will want the next size up and go slow. Grease the specialty reamer to hold shavings unless you plan on removing the top which would be even better to avoid chips in the jug. Both the TimeSerts and Calvan insert are permanent and apply red locktie to them. These are different than helicoils because they are one piece threaded on both sides.

Ive used both as i own an 01 F250 with the dreaded modular 5.4 engine. Ive used both and they both are a hell of a lot better than the helicoil. A helicoil thats just a spring in a sense can leak compression and fluids passed the plug. More info can be google. Yes they are expensive (more) but if you want permanent and no worries, go with quality. Both can be slowly ground and most likely customer service will make you a specific length. EVERY FORD DEALERSHIP WILL HAVE THE KIT OF TOOLS OF DIFFERENT SIZES, SAVE YOUR MONEY AND RENT THE KIT FROM A FORD TECH AND JUST BUY AN INSERT OR TWO FROM TIMESERT/CALVAN (your choice). Yes a helicoil will work, but the rigidity of the others are much stronger being one solid unit.

If it was mine, i'd be on the phone with Calvan because of the permanent stabling pin. Ive had TimeSerts back out with the plug after time.

I have experience with both and can do them with my eyes closed. Ford quotes $800 per plug blowout. FFFFFF that! 20 mins a plug on my truck and even without them blowing, i plan to oversize them prior to a blowout.

If youre worried to attempt, send the jug my way and ill do it free of charge no problemo bub!

Or just drop a match in the hole on every compression stroke and plug with finger.

 

[HusqyStihl]

Use the threaded insert style repairs for spark plugs, the regular wire coil removes too much of the sealing surface for the spark plug and thus the spark plug will not seal well. These inserts come by many names and one of them should be available at your local auto parts store.

Example names:
Heli-Coil Save-A-Thread
Fix-A-Thread Plug-Saver

The best insert repair available is a Time-Sert specifically for spark plug threads, but those kits run $160 without inserts.

If you can't get an insert to work I have welded, drilled and tapped a new threads many chainsaw cylinders.

Check out Calvan, theyre comin up quick with their holding pin design...