Hi

I think I would stake the side with a punch while you have it down in there and call it good!

You are talking about blow by coming through those threads when there is a gasket on the plug that seals the top off shoulder.

When comparing a few thousandths of clearance to the volume amount of the cylinder just how much could possible pass in a few milliseconds anyway.

If you want to coat it anyways and feel better that you used a few drops of that stuff.
You could try using a pair of snap rind retainer pliers and put the tips in the bore. Squeeze them tight to open to grip the bore and twist.

If it doesn't come out then it is meant to be left in there and up to the 15 ft lbs of torque to seal it off.
This plus all the lateral clearances are pulled up in one direction and the plug body crushes the sealing gasket.

If the threads were of a great concern they would put in tapered dry seal threads. Yes, the same as use on pipe threads. NPT

Of course there is another thread that the British invented called a gas sealing thread. It's design gets used on aircraft but that might be a bit of overkill for spark plugs.

Still you got to hand it to those Brits and Yanks to be separate. Visit Britain for a spell and you will hear that they still refer to us Americans as colonists.

If you thought HeliCoil was unique, you should see the fit up on those. Special taps and dies!
Check it out here.

http://www.ralstoninst.com/news/story/the-difference-between-npt-bspp-and-bspt-seals/
After you see that, think about our threads, Withworths and metric come from?

Everyone want a piece of the pie and I don't mean Apple! (:-)

Phil

Kindly and Learned Folks,

What I pulled out when checking spark plug gap a few weeks ago. The wee green 1992 240 beastie was blowing the socket 2 OBD code 2-3-2. Exhaust in no way smells rich. The airbox flap valve defeated my anti-hot air flap valve. I removed the preheat air hose and preheat flap valve assembly. Put in a new Mahle LX-59 air filter. I used Goop RV on the AMM to TB accordion accordian hose to seal it years ago. Still good. No vacuum leaks. Both the TB and air intake gasket are getting brittle, though.

I put anti-sieze on the thread of all spark splugs. The center anode electrode is getting short. Time to install (used) new spark plugs, the Bosch Super Plus.

Yet the sleeve came with the spark plug as I check gap. Two weeks ago.




The high temperature thread locker compound is for application to the exterior of the thread sleeve insert to secure it in the thread of (a) prior owner's repair to the #4 spark plug hole on this 1992 green Volvo 240 GL with horrible abused feel sorry for it M47 II and LH-3.1 and the aggravating (at times - more so in cold weather) iPd (I guess) turbo sport exhaust.

This is a NAPA product spark plug thread sleeve I mean to replace, with another, longer, NAPA thread sleeve insert. Not my choice and I don't wanna recut thread to suit a heli-coil or other threaded sleeve for spark plug thread repair product. (The next outer diameter size up kit from NAPA runs over 300$ And I'm poor in spite of three university diplomas I earned and paid for myself. (Why, in part, I'm a bastard and an SOB much of the time.)

I have nickel (or the other one, not lead Pb) high temp anti-sieze for the spark plug thread.

So, is the sleeve to long? Will it interfere with the spark plug, uh, sparking? I mean to file it down. by two thread turns. As HillBilly recommends.

Phil, I had a Heli-Coil repair kit with the drift you tap to spread the knurled outer thread at the top of the Heli-Coil sleeve. Came in a hanging package with yellow color cardboard slide out backing. For a relatives' 1979 240 DL wagon in the 1980s, though used again with replacement sleeves on others' autos. I had to do it to two of my prior 240s from prior owners distressing the thread, and it stripped on my replacement.

I want to avoid removing the cylinder head, ha-ha, which is so much fun to do without a garage. Like rear wheel bearing inspect, clean, and grease repack. Or replace the front flexi brake lines.

Now to the images. Two are new.







I pulled a set of these four Bosch Super Plus from an NA 940 a year ago. I pull spark plugs from junkyard cars many times as sometimes they are newer then the spark plug sets I have in the cars I own. So, like a Pokemon, I choose you, Pikachu, er, this used set of Bosch Super Plus spark plugs for the engine. The center electrode has crisp shoulder and is (relatively long and the ground electrode (cathode?) shows no thinning or rounding. (The numbers match, unless i screwed that up also.) Though the Volvo 940 I pulled these from was running really rich, as you can see.

Please advise. Thank you folks.

Chronic Athlete's Foot for Months Now MacDuff.
(Wanna an image of that, too? HA!)
Clotrimazole to the rescue? Bleach the shoes, again. Blames the unending fleas in this Midwestern slum hell hole apartment and flea spray with anti-flea hormone stuff. I have no pets.
--
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threadlock is the last you want to apply to a spark plug.

if you use anything dab antiseize on the threads

why don't you just get another set of Bosch plugs. Or Champion N9YC (C for copper)

Don't use that licktite on sparkplugs....if anything spray a little silicone spraylube on the threads before you hand screw them in place.

Hi Kitty

I also would be skeptical about whether the red thread locker or thread locker will hold under those temperatures as the combustion temperatures are all over that zone stated on the package.
In fact, the removal procedure for thread lockers are to heat up the item to loosen it!

The heads metal is probably cooler since there is water in the cooling passages.
We know that the temperature of the ceramic portion the plug is less than a melting point of silicone spark plug boots. Then again, the ceramic is a poor conductor of heat.

Now that I'm talking about conduction, How is that stuff for the grounding of the spark plug?
That would be a bigger concern for me, than whether, it holds the insert!

I have not seen or used that type of thread insert you have for a car.
I have repaired bolt holes by screwing in a bigger piece of threaded stock, welding it and then machining the original bolt size back. I have even stubbed shafts back to life.

I'm more familiar with the Helicoil brand thread repair systems.
In theses cases, it is a stainless steel wire that is formed in the shape of a V-sharp thread on the inside.

The outer part of the coil is formed to fit a special designed helix. Therefore, it requires its own special tap to form its threads in a hole.
The coil is placed and set into that formed thread with its own center tang.

When installing the coil it is turned into the helix until it breaks off the tang. The torque and the snap off, sets the tightness and depth of the insert.
They are commercially used is materials too soft, to tap threads into or of a material make up, not compatible with fasteners.

For cars their stainless steel alloy does not interact with the aluminum but still provides electrical conduction.
I believe you can still use an anti-seize compound if desired.
I have not seen nomenclature either way on that from Helicoil. I doubt it can hurt anything though.



If you still want to use that insert I would definitely shorten it like the other poster said.

It looks from the top that it is made to bottom out against the last turn of the thread. So you need to turn it in until it stops down tight.

Did they provide you with a stub tool to do that?
The insert should fit loose on the tool so it will release after being torqued in.

There are two ways to mechanically stop that insert from turning out.
This first one will lessen the likelihood and is easier to do than the second due to its location.
You want to ding up the outer thread of the insert to take up excessive clearances between the threads radially and clearance latterly.

You want to flatten the outside top of the threads with a light hammer while it is screwed onto a spark plug.
Work on the upper portion of the body so the bottom end that starts first will not be harmed.

I know it sounds hokey but if the clearances, are not excessive, it will add more resistance to the insert turning out, before the spark plug does.


The second method is to "stake" the top of the insert into the head.

Since the head is still on the car the best way to do this is not possible.
Normally you would be best to stake the bottom of the insert so the thread would be spread out and be harder to come up.

After threading in your insert,
You will need to take a small pointed prick punch or center punch and place pricks or dimples around the perimeter of the insert where the seams join together. This creates a key or disruption in the surfaces to rotation.

In lots of cases, two will do just fine, but some machinist and mechanics prefer to use three equally spaced dimples to keep an item or thread in this case, held more uniformly in roundness.

After doing this staking procedure you will want to used a spark plug tap or thread cleaner to clear up the first thread so it will not interfere with screwing the spark plug.


I say this because, not all "pricks" end up where they are intended to be! (:-). It's a tight place down there!
SORRY, I meant, down there where the spark plug goes! (:-)

So ok! That's enough, you get the idea!

Hope this give you more options than trusting a resin.

Phil

I would definitely shorten that Redi-Sleeve so that it is flush with the end of the spark plug.

How are the threads in the head?

I don't believe that Locktite is suitable for that application......Just my opinion...YMMV.