spark plug hole

[coolhandblack 45]

Hello all,

I went to change the spark plug on my wheelhorse today (1276) 12hp. WHen I got it out, i realized that the threaded hole that the spark plug screws into had came out with the spark plug. I hope you guys know what I am talking about. Well I got the threaded part off of the spark plug and the bottom portion was cracked, I broke off the two bottom threads and screwed it back onto the spark plug then reinstall the spark plug back onto the engine. I gave the tractor a decent workout after doing this and it ran pretty good. I am just worried that I screwed up something bad. Help ease my fears or point in the right direction on how to fix the problem. Thanks for the help all!

Coolhandblack :banghead:

[rustbucket 4]

sounds like some time earlier in the engines life the plug hole striped out and someone fixed it with a thread insert it should be fine as long as the plug dosnt get a mind to fly out. J/K i have seen it done alot in the air force when fixing ground support equipment so no biggy if the us air force dose it it has to be alright.

[pond195520032003 27]

sounds like it has a heli-coil, thread repair if it keeps coming out i would go ahead a find a re placement head :USA:

[kpinnc 13,954]

Coolhandblack,

I had to replace a threaded insert on a K-321 head recently. The kit I used had inserts with tiny teeth facing outward at the top of the insert, and the included punch tool in the kit forces them out after you install it. The teeth prevent the insert from turning after they are swedged out, so the insert won't come out with the plug later.

The inserts I used in the military were different. They had a tab on them that we'd break off after installing. It forced one of the threads of the insert to swedge out, presumably for the same purpose as the teeth on the HeliCoil brand inserts.

I've only used the HeliCoil brand once, so if my description sounds silly or elementary, I apologize. The insert I pulled out of the head on my engine was nothing like the one I replaced it with, so I figured the newer one was an "improved" version. It was also much larger in diameter, so you had to use the included tap to cut new threads into the head.

I said all of that simply to say this: You may still be able to save the head by using a newer HeliCoil. I'd just take it to a good auto parts store and compare it to the newer kits...

Mine was a "Sav-a-thread" by HeliCoil. It cost me about $25, and comes with all the tools to do the work. You can buy additional inserts seperately later, if you need them. I think it came with 1 each of 3 different sizes.

Good luck!

Kevin

[illinilefttackle 399]

:USA: I don't know if this helps-but I had the same thing happen to me after I used a thread repair kit in the spark plug holes of my 1959 Johnson 35 Outboard. The hielicoil kept coming out when I changed plugs-SO-I put a little Hi -Temp Loc-Tite on the outside of the coil-them screwed it back in using the spark plug. Never had that problem again!-AL :banghead:

[WH854 44]

I just had one done by a lawnmower shop.He is a Kohler and Briggs Dealer.

He retaped the hole and then put a Heli-coil in it This fellow told me he had done hundreds of these in his 30 odd years. He also an ex Wheel Horse DealerIt workes great.

Chs From Butler Pa :banghead:

[Kelly 1,032]

Heads are cheap, around $20 or less with shipping off ebay, and it's a good idea to pull the head and clean the carbon off everything every couple of years, and install a new gasket, but that is my opinion.

[linen beige 14]

Heads are cheap, around $20 or less with shipping off ebay, and it's a good idea to pull the head and clean the carbon off everything every couple of years, and install a new gasket, but that is my opinion.

my thoughts precisely!

If the hole is stripped where did the shavings go? Are they in the engine? To be sure they are not foating around the tops of the rings, the head should be pulled and the crud cleaned out. If the head is off for this step, and a new head is about the same cost as the Helicoil "fix", why not just replace the head?

[BPjunk 184]

If the hole is stripped where did the shavings go? Are they in the engine? To be sure they are not foating around the tops of the rings, the head should be pulled and the crud cleaned out.

Always remember to have the engine on EXHAUST STROKE when rethreading a spark plug hole. Ths way after cutting new threads you can use compressed air to blow the debrie out the exhaust port.

Wild Bill in Richmond, Va.

[WH854 44]

I took the head of my engine to have it done.If you buy heads on ebay you

are taking a chance on them being warped. and they might not have enough

head left to shave of and be safe,for room for the valves. Might bang into

the head.

Beside I have never seen a new head on ebay for 20$ you also may run into

a bad thread again. Sohars http://www.rcpw.com/ has an 8hp Kohler for over

a 100$ new.

Chas from Butler Pa :banghead:

[kpinnc 13,954]

Always remember to have the engine on EXHAUST STROKE when rethreading a spark plug hole. Ths way after cutting new threads you can use compressed air to blow the debrie out the exhaust port.

That's a good point Bill!

And I apologize- I put the insert into mine while the head was off of the engine. It didn't occur to me that it was sometimes done with the head still on the engine...

Chas is right too. Though Ebay sometimes has them fairly cheap, you just never know what you're gonna get until you get it. Add shipping costs in, and you can end up right back where you started. Besides, a properly inserted HeliCoil is at least in my opinion, a better option than even a head with "decent" threads. Since the head is cast aluminum, and unless it is brand spanking new, the HeliCoil is gonna be stronger than the threads in the head. After all, you've just cut new threads into it, and since the insert is steel, you won't have to worry as much about cross-threading a softer material like the aluminum if you remove/replace the spark plug later.

Just my $.02....

Kevin

[linen beige 14]

Always remember to have the engine on EXHAUST STROKE when rethreading a spark plug hole. Ths way after cutting new threads you can use compressed air to blow the debrie out the exhaust port.

Wild Bill in Richmond, Va.

That is certainly a step in the right directon Bill, but aint it taking a pretty big chance that you just may drive a sliver down next to a ring? I mean, it is awfully hard to see what's inside a cylinder when you're peeking through a spark plug hole.

I think if you are going to use an insert to avoid buying a new head, you should at least take the head off. That would give you visibility of how the insert is really fitted, and give you a chance to clean the carbon off everything to boot.

As y'all can tell, I'm not a big fan of Helicoils, and must admit that comes from bad experiences with them in the '70s and '80s, (I can still remember watching a 7 horse Briggs spit the plug into my dad's chest when he started it up!) but there are some other brands of inserts that are actually threaded, one piece sleeves, that are a lot stronger. I've not used any, but the Timeserts look like a very good product.

[TT-(Moderator) 1,156]

If you want the easy way out, have the existing (stripped) hole opened up to fit a spark plug for a TRA-10 or 12 D Wisconsin engine. I have a tough time remembering sizes, but I believe the original Kohler spark plugs are 14 m.m. and the Wisconsin spec plugs are 18 m.m. (The NGK number would be A-6 or...... Champion is D-16J.)

Depending on the style of the tin cover over the head, the spark plug access hole may need enlarged slightly.

For those of you worrying about aluminum shavings dropping in to the cylinder if the head is left on to install the insert - don't sweat it. Pack the flutes on the drill bit and the tap with grease and the shavings won't go anywhere but there.

BTW -- there's a company that makes solid inserts with shoulders (or flanges) that will not screw past the top surface of the head. (or whatever else you use them on.)

That's always been my biggest gripe with a heli-coil - they can screw right on out the other side of the hole. (unless, of course, it's a blind hole.)

[Kelly 1,032]

I didn't say new head, and yes it's a chanch you take with ebay. I'm sure a member here could set you up also, and have a better chance at getting a good one.

I've used helicoils on many things with out a issue.

But it's still a good idea to clean the carbon every few years, remember to retorqe the head after it's been run 10-15 min let it cool for 5 min or so first, and use the right patern so you don't warp the head.

[WH854 44]

You are right Kelly you didnot say new head. I apologize for saying that.I

Am :imstupid:

Chas From Butler PA :banghead:

[Kelly 1,032]

No biggy.

[Sarge 3,464]

Heli-coil insert repairs are the cheap way to fix a plug hole , no offense intended . Timesert inserts are expensive but much more permanent and do require a larger outer diameter (Kohler heads should be fine) . Kits are available that include the needed swaging head to "set/seat" the timesert so it doesn't come back out . Makes you pretty nervous giving that kind of love tap when seating to something so expensive ...

Sarge