Need advice on spark plug repair kit to buy?

[Lone Wolf]

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Need specs? What tap who makes it? Also you need to assemble it with the plug in and pressure test before we can be sure.

 

[Mattyo]

Ok, so using that same exact kit you posted... yes, the tap was rubbing a bit at the tip. So I did some MINOR grinding with the dremel, and the m14 part stopped rubbing. the 17mm tap ran fine in there... if this is off center at all, its very minor.

OH!!!!!!

MY BAD MY BAD!!

If your threads are buggard in the first place the m14 can't bite....

my threads were fine.... so I can now imagine that the tap goes off center if your plug hole is all wallowed out

 

[Lone Wolf]

Ok, so using that same exact kit you posted... yes, the tap was rubbing a bit at the tip. So I did some MINOR grinding with the dremel, and the m14 part stopped rubbing. the 17mm tap ran fine in there... if this is off center at all, its very minor.

OH!!!!!!

MY BAD MY BAD!!

If your threads are buggard in the first place the m14 can't bite....

my threads were fine.... so I can now imagine that the tap goes off center if your plug hole is all wallowed out

Exact same kit? Now we need an opinion on the combustion chamber you ground. Tomorrow I will try what you did on a junker.

 

[Mattyo]

Totally agree that if you want it straight, bridgeport is the way to go, BUT... how can you mount it and be confident its perfectly perpendicular? Thats always the issue. So, with this kit, as long as you drive it close, it really seems to be ok. The inserts seem pretty stout, and I've had good luck putting these in with jb weld. ... I tried the black RTV they recommend and its crap.

But i'll bet your hole was really wallowed out. So, get out the dremel with a round end carbide, and grind out where its rubbing....just like I did. Then you can drive that tap straight.

 

[Mattyo]

I really didn't grind much...

 

[Lone Wolf]

Totally agree that if you want it straight, bridgeport is the way to go, BUT... how can you mount it and be confident its perfectly perpendicular? Thats always the issue. So, with this kit, as long as you drive it close, it really seems to be ok. The inserts seem pretty stout, and I've had good luck putting these in with jb weld. ... I tried the black RTV they recommend and its crap.

But i'll bet your hole was really wallowed out. So, get out the dremel with a round end carbide, and grind out where its rubbing....just like I did. Then you can drive that tap straight.

I want to know if it holds pressure.

 

[Mattyo]

I have a hard time believing it wouldn't. Put it in with JB weld.. then ya gotta wack it. That mandrel needs a couple good wacks.

Buy extra of those inserts on ebay. ...if you buy a bunch they aren't too bad.

 

[twinstaged]

well I could set the job up to do it. Does your machinist friend not has his own shop to do it?

 

[Mattyo]

you *could* indicate flat off of the area that surrounds the plug... the "seat" area ... that might work.....but ya also gotta figure out how to hold the cylinder exactly in that position....

 

[Lone Wolf]

well I could set the job up to do it. Does your machinist friend not has his own shop to do it?

He dont have that machine he's retired .

 

[twinstaged]

They do make heat proof thread locker that would make sure it's sealed and never coming out without total destruction

 

[Lone Wolf]

I have a hard time believing it wouldn't. Put it in with JB weld.. then ya gotta wack it. That mandrel needs a couple good wacks.

Buy extra of those inserts on ebay. ...if you buy a bunch they aren't too bad.

What did you install it with a spark plug? How much torque did you apply?

 

[Lone Wolf]

They do make heat proof thread locker that would make sure it's sealed and never coming out without total destruction

Name of it brother?

 

[Mattyo]

The threads are loose enough that you don't necessarily need a sparkplug to insert it. You can do that, but you have to take out the plug once the insert is seated, and THEN wack it with the mandrel to allow the teeth to bite in. The jb weld seals around the threads to prevent leaks.

really no torque is needed... just seat the insert slightly below flush with your finger, and then wack it.

 

[twinstaged]

Resbond 907. It's good to 2100 degree F. It's overkill and I'm sure anything permatex offers as "high heat" would work.

 

[Mattyo]

just for the record....I'm not a machinist. my grandfather was a prototype tool and die maker back in the day, and I learned a few things from him ... but i will encourage anyone reading this to not take my word as gospel lol

what I do know is that often the key to machining on the bridgeport is to mount the work to the table correctly... and cylinder heads are tricky

 

[twinstaged]

H'll even the high temp jb weld like stuff would probably be trust worthy.

 

[Mattyo]

http://www.cotronics.com/vo/cotr/rm_threadlockers.htm

 

[Lone Wolf]

http://www.cotronics.com/vo/cotr/rm_threadlockers.htm

Going to buy some Matt?

 

[Mattyo]

the jb weld I used was on a saw a year+ ago.... the guy is still using it... so i'll stick with the jb weld. ..but nice to know there are options out there