The last word in thread repair

Somewhat surprising results.

Nice one!  Thanks for posting.

Where I work, in the aerospace industry, almost all threads in aluminum or similar, require a threaded insert, and 90% of the time, a helicoil is used.  Not helicoil brand, but a stainless spring insert.  I've heard reports of guys using helicoils for spark plug repair, only to have the insert spin out at some point later.  For thread repair like that, a solid insert may be better.  I've heard that they don't transfer heat to the spark plug the same as raw aluminum, though.  Not sure how important this is.

Seems like a couple of guys here replaced failed helicoil spark plug repairs with timeserts.

Nessism wrote:

Nice one!  Thanks for posting.

Where I work, in the aerospace industry, almost all threads in aluminum or similar, require a threaded insert, and 90% of the time, a helicoil is used.  Not helicoil brand, but a stainless spring insert.  I've heard reports of guys using helicoils for spark plug repair, only to have the insert spin out at some point later.  For thread repair like that, a solid insert may be better.  I've heard that they don't transfer heat to the spark plug the same as raw aluminum, though.  Not sure how important this is.

Not sure about "heat transfer" however a stainless insert could "potentially" cause a weak spark as stainless is a poor conductor and current is very low in a HT circuit

TexasKZ wrote:

Seems like a couple of guys here replaced failed helicoil spark plug repairs with timeserts.

Personally I've never had a problem with helicoils but I guess like anything else, the quality of the repair and the parts used are a factor

By repairing a sparkplug thread, i prefer only solid inserts, ( like timesert or like that´s) ,and no helicoil sprins inserts, about negative experiences with the helicoils on that special place...The basic problem with steel inserts in aluminum is that the thermal expansion coefficient for aluminum is twice as high as for steel or stainless steel. As a result, there is always the risk that the inserted threaded bushing will become loose when the spark plug is (repeatedly) unscrewed

The best solution in this case is to secure the threaded insert in some way! Such as using high-temperature loctite, or caulking, clamping, expanding the inside of the socket... just to secure it against twisting/loosening!
 

TexasKZ wrote:

Seems like a couple of guys here replaced failed helicoil spark plug repairs with timeserts.

Timsert is the right way to do it. 

Warren3200gt wrote:

TexasKZ wrote:

Seems like a couple of guys here replaced failed helicoil spark plug repairs with timeserts.

Timsert is the right way to do it. 

Spark plug repairs with Würth timeserts....



 

I don't disagree that "timesert" is the "gold standard" in a professional workshop/machine shop but man for a "once in a while" tool they are seriously expensive

Sure, Wook, i agree full about the price, "Würth" is an realy expensive choice,..BUT:This video actually explains it best! It is also important that the socket has a collar at the top

That doesn`t meant, that it is the only one, i have a plug-threat renew-kit from an nameless manufaturer, and it works same way, with same style inserts and installations tools..!

Here you can see the tool-set, i do my work withit...(( and as Wookie58 mentioned before: For rare and  "sometimes" repairs  in a hobby it´s good enough and the inserts are still sittin`as they should,...but if i had to do it as an professional day by day, i would buy the "Würth"-setup! - Just my opinion

If you already have a collection of taps you can make your own timesert kits for the cost of the inserts and a spare bolt.

Step one, buy and measure your Time-serts. Typically the OD of the insert is 2 sizes up from the screw size, with the same pitch. For example a M10 x 1.25 bolt will use an insert with an OD of M12 x 1.25

Step two, drill the hole for the correct tap size

step three. counter bore the hole approximately 1 mm, you will want the counter bore to be as close to the diameter of the lip on the insert as possible, this will mean using a counter bore with a pilot smaller than your hole. wrap some masking tape around the pilot on the counter bore to help the bit self center in the hole, oil the outside of the tape after. You are removing very little material here so the tape should last long enough for one or two holes. If you don't have a counterbore set, you will need to buy one. They can be had for as cheap as $37 on ebay and can be used for your other projects as well. Otherwise you can do it with a drill bit but be carefull because they will want to catch and dig in.

step 4 tap the hole.

step 5 file four sides of a bolt thread flat, it is the same size of the insert ID. Take just enough off to take the thread down to the minor diameter of the threads. this is your insert driver.

step 6. make sure the tapped hole is clean and dry, thread the insert into the hole. Oil the driver and thread it into the insert all the way through the opening, thus expanding the insert and making it permanent.

It works great, i just did this on a bandit 1200. The valve cover uses M7-1.00 threads and I didn't want to pay $80 for a kit that i will never use again. Enter M9-1.00 Chinese tap on ebay for $5....

   

Now that's the kind of solution that excites a "cheap Wookie"