Spark Plug Thread Repair Kit Suggestions?

l008com

Well-Known Member
Joined
May 25, 2015
Threads
47
Messages
268
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.
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
63
Messages
15,771
Here are two suggestions I have in my toolbox. Depending on how bad the thread are botched, will dictate which tool you need. If you purchase a kit, make sure it contains the proper length insert.


You can google search “spark plug thread repair kit” to find a kit which best meets your needs. Drill size I use is .500”.
 

Auto Doc's

Lawn Addict
Joined
Sep 7, 2024
Threads
19
Messages
1,814
What are the numbers on the engine.

I recommend removing the cylinder head.

You need to make sure you install the appropriate length insert to match the plug used in the engine.

Here is a good video:

 

Tiger Small Engine

Lawn Addict
Joined
Dec 7, 2022
Threads
3
Messages
1,626
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.
Many times when removing spark plugs from customer engines, I find the plugs to be too loose. I think they are afraid of stripping it. Anyway, I have two engines with stripped spark plug threads and one engine with stripped carburetor bolt threads I will work on this winter. Occasionally people call about spark plug thread repair, but I don’t offer this option. Helicoil is a popular brand and holds up.
 

l008com

Well-Known Member
Joined
May 25, 2015
Threads
47
Messages
268
I've only used a helicoil once on an MTB brake caliper and it works really good. The only issue was that it was really hard to keep the tap perpendicular to the hole I was trying to thread. But I did get it eventually, thankfully. These carbon fiber frames are not cheap! But the way spark plug taps work, it should be even easier to do it right.

Now necessary is the thread sealer though? Wouldn't the kits come with it if it was really necessary?
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
63
Messages
15,771
I always use Lotite blue on any threadsert I install,
 

l008com

Well-Known Member
Joined
May 25, 2015
Threads
47
Messages
268
Isn't loctite just going to burn off after a few minutes of running the motor?
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
63
Messages
15,771
I’ve never had an insert come loose in my 50 years of experience.
 

StarTech

Lawn Royalty
Top Poster Of Month
Joined
Feb 19, 2020
Threads
119
Messages
12,734
spark plug helicoil repair kit

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.
 
Top