Logo
FULL SITE MENU

Possible galled spark plug threads - any advice?

G

grey2112

Contributing Member
So I was pulling my plugs on my Honda 250 (2013 with 1000 hours) and one of them was VERY hard to remove. When I looked at the plug it appears that the first thread was a little crushed/galled. Trying to screw it (as well as other normal looking plugs) back into that particular hole was VERY tough, so I stopped trying to force it.

I am going to try and use a spark plug chaser to clean up those threads and if that doesn't work then I will try using a back tap thread repair tool.

Any advice as I have never done this before. Should I use any type of grease or anti-seize on the tools?

My research on anti-seize for spark plugs is giving me lots of different diametrically opposed options. I understand that the torque needs to be less if you use an anti-seize. I am wondering, though, given the salt water environment and dissimilar metals, if I should be using a non-copper or non-nickel based anti-seize, say something like Jet Lube for this?

Thanks!
 
I don't know enough about the options to comment, but I will say you should be using SOMETHING to act as an anti seizing agent on those threads!
 
If you're talking about using the Jet Lube Marine Grade anti sieze compound I wouldn't. It is non conductive and that's not desirable for spark plugs as they need to be grounded.

If you do end up using a tap or thread chaser I recommend making a plug from a paper towel and twisting it into the plug hole. If you top it with the grease you use to lube the tap any shavings will be captured and removed when you extract it from the hole. A decent pair of thermostats is a good tool for doing this chore.

If you need to do thread repair, use an appropriate sized Time-Sert kit and not Heli-Coil.

Good luck.
 
jgmo said:
If you're talking about using the Jet Lube Marine Grade anti sieze compound I wouldn't. It is non conductive and that's not desirable for spark plugs as they need to be grounded.

If you do end up using a tap or thread chaser I recommend making a plug from a paper towel and twisting it into the plug hole. If you top it with the grease you use to lube the tap any shavings will be captured and removed when you extract it from the hole. A decent pair of thermostats is a good tool for doing this chore.

If you need to do thread repair, use an appropriate sized Time-Sert kit and not Heli-Coil.

Good luck.
Click to expand...

Thank you - do you mean "hemostats" for picking the paper towel "plug" back out again?

I tried using a back tap thread repair tool but unfortunately it isn't long enough to operate properly - these damn Honda outboards have the spark plugs so deep in to the block I would need a tool at least twice as long to operate it properly.

https://www.amazon.com/gp/product/B0014FGVVW/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1


Wondering if anyone makes a longer one - I like the idea of cleaning and "repairing" this from the inside out, especially as it would capture shavings.
 
Ha ha, yeah! The dang ever handy spell check slipped one by me. Yes, "hemostats" for fishing out the paper towel;>)

As far as chasing the threads, I don't actually do this these days but my solution MIGHT be to braze (silver solder) a tap on to an appropriate length rod if necessary.

Lisle tools also makes several different spark plug thread repair kits that get good reviews on my IATN account.

Like this one:

https://www.nationaltoolwarehouse.c...MIpumB9LjT8AIVIB-tBh0mUQzsEAQYAyABEgLwmPD_BwE

Good luck.
 
Here's another Lisle tool you may be interested in trying.

https://www.amazon.com/Lisle-20020-...t=&hvlocphy=9031520&hvtargid=pla-561914302730

I forgot to mention that it's always a good idea to bring the cylinder that you're working on to Top Dead Center (TDC) before putting anything in the hole.

An obvious point to some, I know, but worth mentioning since we're on the subject. I never liked doing stuff like this because it can go wrong easily if you don't take your time.

Best of luck.
 
So quick update - I VERY VERY carefully deployed two different thread chasers, lots of grease, going slowly and backing off when I encountered resistance. End result? Everything seems to be good! I can now hand-thread in a spark plug just like the other 5 holes. VERY hopeful this will solve this issue and I learned a lot of valuable lessons regarding proper installation of spark plugs. Best new practice - using a piece of fuel hose to start the plugs by hand so as to get a better "feel" for them going in. Also learned Honda spark plug holes are WAY too deep.

BTW, jgmo - I bought that EXACT Lisle tool and used it and it was invaluable. VERY happy with how this turned out and hoping it keeps any issues at bay. I am a little worried about aluminum bits in the engine now due to my initial fudging up of things, but I used a lot of grease, magnets, etc. to draw out as much as I could and hopefully any remaining won't mess things up too much for the next 5-8 years I hope to run this motor.
 
Well.....

....the one good thing about aluminum...

...in this case....

...is that it's SOFT.

If you did get a chip or two in there, it will likely just spit out the exhaust when you fire her up. Hope so anyway.

GOOD SHOW!

Glad you got it!
 
Back
Top