The spark plug came out of the hole. Now it needs a helicoil and a tap to re-thread the hole. Where can I find both the helicoil and tap?

Time Sert? Question edited to what I think you meant to say!

You go to an engineering firm and get a Helicoil Threaded insert put in. The make the hole a fraction bigger and put the Helicoil in. The centre is the same as what was there before, but made of steel instead of aluminium.

Or you can do it yourself.

https://www.google.com/search?q=spark+plug+helicoil+insert

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Your local part store should carry a spark plug hole repair kit. Just make sure you keep the metal chips that get made from cutting the new threads out of the engine. Get some axle grease and coat the tap so that the chips will stick to it instead of falling down into the engine.

Take it back off, Buy a helicoil set. Basically.. Drill the hole out, tap it out to a bigger size. insert the heicoil(which reduces it to the size of the bolt.. A good heicoil set will have the drill bit, helicoils, tap, and the tool to insert the helicoil. Put down rags to catch the metal shavings while drilling and tapping. Then clean the tapped hole(Brake clean and blow it out with air) and use thread lock on the helicoil. Make sure the helicoil sets down below the surface..

The best way is to measure a bolt of the same size and pitch as was fitted in that threaded hole. The specs are the same for both eg M10 x 1.5 or whatever. Then you can take this info, or better, the bolt itself, along and buy a helicoil kit to suit.

If it is for a spark plug hole, they will know immediately on seeing one of your spark plugs (there are 2 main sizes). It is probably also on the back of the kit packet.


The other way is to drill and tap out the hole for a larger size screw or bolt than you had to begin with. Generally you would use a tap drill for the next larger standard size thread.

THere are really only 2 ways to fix this, and you must be mechnically inclined to do it. You have stripped the thread in the head so you either have to 1) replace the whole head assembly or 2) get the spark plug hole tapped and rethreadded.

some dealers have special tools to do this in the car. Call a few and ask them. Did plugs break off in head? Or were threads damaged when plugs were removed

Try to put duck tape around it.

The Spark Plug hole can be repaired. The professional way is to remove the cylinder head, and use a repair such as a Helicoil.

The spark plug hole is tapped out to a larger thread size, with a special Helicoil tap. Loctite or some other form of thread locker is applied, and the Helicoil is inserted.

Helicoil's are made of Stainless Steel, and are much better than the original material used in the cylinder head. (Be it cast iron or aluminum)
Drag racers use Helicoil's in their engines.

Tapping out the spark plug hole for a Helicoil, or using a special thread chaser, is NOT a good idea, while the cylinder head is still installed on the engine.
The tap creates chips of metal which fall down into the cylinder.
Using a vacuum to try to alleviate the chips, falls short of a good repair job.

Quick Tip. Take one old spark plug and saw an X across the threads on the bottom with your hacksaw. Clean away the filings. Oil it and thread it into the spark plug hole. This is called re tapping. Then try the new plug again. Has worked many times for me.

Carefully inspect the threads it sounds as if you have a crossthreaded hole that isn't allowing the plug to full seat. You'll need to get the proper size threading die and very carefully recut the threads. Best done in a shop as if anything falls into the cylinder your looking at very expensive repairs. It happens quite frequently with aluminium blocks and needs to be fixed as a spark plug popping out lets hot fuel dump into the engine compartment. Here is a description of such a tool at toolmonger.

It can happen to the best of us: one moment of inattention results in a cross-threaded spark plug hole. You can either install a helicoil and hope for the best, or send it out to have the whole shebang re-tapped. Now you have another option. The Back-Tap can fix that cross-threaded hole from the inside — without pulling the head.
The Back-Tap is a tap with expandable threads and a mandrel to catch errant metal shards. Apply a dab of grease to the mandrel, then place the device in the hole past the damaged threads. As you back it out, the cutters expand out to engage the undamaged threads, then gently reshape the damaged ones. The greased mandrel keeps metal filings from ending up in the cylinder.
The result: a task that could potentially take days and cost hundreds of dollars is done in minutes for less than a hundred bucks.
MAC offers a three-piece kit that includes a 10mm, 12mm, and 14mm Back-Tap for $90. You can buy Individual taps from various sources for about $50 each.