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After 19 seasons, The threads in the spark plug hole are stripped. Other than getting another head, any suggestions?
Thanks

A Heli-coil insert repair kit is what you want. The local hardware store should have them in stock. If you don’t mind spending a little extra money a machine shop can do it all for you.

Heli coils are goos anywhere the hole does not need to be pressure tight as the wire insert is a poor fit in the thread.
For spark plugs a similar device called a Time scert is a much better way to go.
Similar idea except the insert is both solid and the correct shape for the plug.
No matter which way you go from now on it will be important to put a little nickel ( silver colour ) anti sieze on the plug to prevent the insert winding out when you remove the plug, particularly if the engine is hot.

Thanks Much

bertsmobile1 said:

Heli coils are goos anywhere the hole does not need to be pressure tight as the wire insert is a poor fit in the thread.
For spark plugs a similar device called a Time scert is a much better way to go.
Similar idea except the insert is both solid and the correct shape for the plug.
No matter which way you go from now on it will be important to put a little nickel ( silver colour ) anti sieze on the plug to prevent the insert winding out when you remove the plug, particularly if the engine is hot.

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Thanks, What is a "Time scert", cannot find when I google it.

these things http://www.timesert.com/
Usually you get them from an ENGINEERING supply shop & not an auto parts store.
Most engine reconditioners will have them.
We have a mobile bloke who comes around & does them .
Down here he charges $ 50 call out + $ 15 for each plug.
The gear is a lot more expensive then helicols cause they are better.

Just like Helicoil, there are a lot of generic brands out there a lot cheaper.

Heli-coil is a brand name, they are the biggest in the industry and they make spark plug inserts as well as any other insert you can imagine.

bertsmobile1 said:

g.
No matter which way you go from now on it will be important to put a little nickel ( silver colour ) anti sieze on the plug to prevent the insert winding out when you remove the plug, particularly if the engine is hot.

Click to expand...

Very bad idea anti sieze, don't cross thread the new plug and use a torque wrench if you have one when you install. You should be able to install the new plug with just your fingers and then just tighten to specs. There is a reason the new plug striped out the head. I would price out a used or new head before buying a Heli coil set it might just be cheaper. You will need a complete kit for just one plug, not worth the cost.

Hello,

A new cylinder head is 36.96.

Check Craigslist for a used one.

Regards

Jeff

reynoldston said:

Very bad idea anti sieze, don't cross thread the new plug and use a torque wrench if you have one when you install. You should be able to install the new plug with just your fingers and then just tighten to specs. There is a reason the new plug striped out the head. I would price out a used or new head before buying a Heli coil set it might just be cheaper. You will need a complete kit for just one plug, not worth the cost.

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Thanks for your advice. seems a new/used head is about the same price as a Heli-coil set

https://www.ebay.com/itm/LAWN-BOY-S...617428016?epid=1701701878&hash=item25dcc10830
There are others available there.

blowerhead said:

After 19 seasons, The threads in the spark plug hole are stripped. Other than getting another head, any suggestions?
Thanks

Click to expand...

I cross threaded one and I got a special tap for spark plug holes...different size each end.
I rethreaded with the tap and put my plug back in.

I don't know if you could put something like a serviceable locktite on the threads to help seal it if that would affect grounding of the spark plug.

shiftsuper175607 said:

I cross threaded one and I got a special tap for spark plug holes...different size each end.
I rethreaded with the tap and put my plug back in.

I don't know if you could put something like a serviceable locktite on the threads to help seal it if that would affect grounding of the spark plug.

Click to expand...

Loctite should never ever be used on a spark plug.
At running temperatures it will be soft and when cold it will be at full strength making replacing the plug very difficult.
you would then have to clean out the threads and reapply.
There is a product available that will do the job but it is very expensive and not easy to get, for very good reasons.

bertsmobile1 said:

Loctite should never ever be used on a spark plug.
At running temperatures it will be soft and when cold it will be at full strength making replacing the plug very difficult.
you would then have to clean out the threads and reapply.
There is a product available that will do the job but it is very expensive and not easy to get, for very good reasons.

Click to expand...

I said serviceable Loctite...which can allow removal
The point is...the head is bad and this might allow a temporary fix for continued use.
spark plugs are not removed very often on a good running machine.

reynoldston said:

Very bad idea anti sieze, don't cross thread the new plug and use a torque wrench if you have one when you install. You should be able to install the new plug with just your fingers and then just tighten to specs. There is a reason the new plug striped out the head. I would price out a used or new head before buying a Heli coil set it might just be cheaper. You will need a complete kit for just one plug, not worth the cost.

Click to expand...

Totally wrong.
You should not use anti sieze on plugs going into a normal plug hole
However Helicoils are stainless and time serts are high nickel .
Both of these alloys will gall & sieze when used against a high nickel spark plug.
The makers of the inserts recommend using the high temp anti sieze (not the low temp copper one ).
As do car makers on alloy headed engines with inserts fitted from new, you know people with no idea about engineering like Rolls Royce, Ferrari, Jensen, Healey.
Contry to popular belief a spark plug can ground perfectly well using the base & washer ( where fitted ) against the head, it does not need the thread to make a ground contact

Just my two cents, have installed more spark plug HeliCoils as well as bolt HeliCoils than I care to count, never had one return to bite me. One thing I do is use sleeve lock on each one and it must sit for 12 hours before a plug or bolt is put in them.

Thanks for your replies.
What size Helicoil insert is needed for my model 10323 spark plug hole?

Good used heads on Ebay for 12 - 14 dollars shipped free. Might take a look into that.

tom3 said:

Good used heads on Ebay for 12 - 14 dollars shipped free. Might take a look into that.

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Thanks