Spark Plug Thread Repair Kit Suggestions?

[Hammermechanicman]

was that you at the race track the other day?
View attachment 72329
Or was this this one yours?
View attachment 72330

I wish.

 

[rswapp]

Last Fall, I was winterising my equipment and I accidentally stripped the spark plug hole on my yard vacuum. Its a 31 year old machine and I didn't turn that hard, so its probably a failure that has been inching its way to happening for a while.

But no worries, this is a great opportunity for me to make a video about repairing stripped spark plug holes with helicoil type repairs. I used one of those to fix the brake rotor mount on my mountain bike and it worked great.

So the question is, does anyone have any specific suggestions for a specific kit (with links) that is good and that has everything you need in one kit. Including the drill bit UNLESS its a standard size bit. But I don't think it it, its probably bigger than 1/2" right? So the bit, the coil, the install tool, the thread tap etc.

I know I could also repair this by just replacing the head. But I'm making a video out of it so I really want to use a repair kit rather than a replacement head.

Helicoil is the way to go, quick and easy, make sure to use loctite on the helicoil so it doesn't back out. I use to strip the threads on an old vw all the time then I found copper anti-seize.

 

[Craiger]

Well those are hard to get started and causes a loose fitting. They are supposed to self feed but don't. I recently tried one on the Poulan with a strip plug hole. Almost never got it started and then kept wobbling around.

It is best to use a regular Heli Coil but those kits are expensive. And mainly only shops can justify the costs.

The Runnings link looks like exactly what he needs. I see two problems: Running's only has stores in 12 states. They say it only includes the tap and four inserts, no tool to install nor drill bit. I think more research is needed. From another post maybe it uses a standard ½" drill bit. More importantly, specialized install tool was needed on Helicoils I've installed in the past.

 

[tcpuccio1]

I'm in the auto repair business not small engines. I can tell you 100% if you want a long lasting repair DO NOT USE A Heli-coil! if you have had this machine for 30 years your in it for the long haul and from the sounds of it you do preventive maintenance like changing a spark plug regularly. you may get 1 or 2 chances at it before the heli-coil pulls out of head. Time sert is the only way to go! unless you want to buy a cylinder,head and be done with it altogether. When you put the insert in the head red lock tite on the outside of the cert and you will be good for another 30 years!

 

[Freddie21]

Watch Taryl's video from the 19 min point.

 

[RevB]

For what it is....18mm to 14mm plug adapter. Way cheaper.

 

[golfergordy]

I used a helicoil thread repair kit I bought from aliexpress (for about $6), on a 9HP Craftsman snowblower. During the process of installing it I thought it would never work because it was very difficult to use the rethreading tool. I pounded it with a mini sledgehammer many times because it was so difficult to cut the new threads, and I thought that the new threads were stripped as I tried to cut them, but, when I finished, I inserted the spark plug with the helicoil and didn't tighten it too much. I started the engine and it ran fine. I wanted to use Loctite but thought the heat of the engine would be too much, so I didn't use any. I still need to test the engine again and run it for a long time to have more confidence in it.

 

[sgkent]

... or maybe the guy who doesn't have the time and money to fix it right, but he is fully capable of spending the time and money to fix it two or three times... .

 

[rhkraft]

Not about spark plugs, but if hole strips, check the hole for depth and see if there are enough threads further down the hole. Then use a longer screw or bolt but use one long enough to reach the bottom. Carefully shorten the bolt until it will torque without hitting the bottom. You need to use all the thread available. I have used this in carburetor screws and starter mounting bolts. Never had problems.

 

[StarTech]

Here is something we all should be aware of. A machinist friend tells me for a threaded hole to be at full strength the threads need to be 1.5 x the diameter of the screws. Well this makes these 9.5mm length 10mm plugs holes [2/3 strength] easily stripped and the 14mm short thread [45% strength] even easier to strip if over torqued. Now the 14mm long thread are at nearly 100%.

I used a helicoil thread repair kit I bought from aliexpress (for about $6), on a 9HP Craftsman snowblower. During the process of installing it I thought it would never work because it was very difficult to use the rethreading tool. I pounded it with a mini sledgehammer many times because it was so difficult to cut the new threads, and I thought that the new threads were stripped as I tried to cut them, but, when I finished, I inserted the spark plug with the helicoil and didn't tighten it too much. I started the engine and it ran fine. I wanted to use Loctite but thought the heat of the engine would be too much, so I didn't use any. I still need to test the engine again and run it for a long time to have more confidence in it.

This is probably what you got.

Which is not a Helicoil set but is an insert kit. Very similar to Timeserts

Now this is a Helicoil set that I was looking for. Too bad the company don't a have complete kit like it for the 14mm so I get the next level and getting the 9/16 bit separately. But at least they have the full kits for the 10mm & 12mm plus the extra Helicoil to refill the kits.