A friend of mine has a 2008 Street Glide he bumped up to a 103 using Dave Mackey parts including the heads. He stripped the threads in the rear cylinder head yesterday and is looking at the Heli-coil option to fix it. Anybody have anything good or bad about that option.


Some have also recommended the Time-sert inserts.

 

I've done them plenty on fords that would launch plugs out of the head, get some sort of vacuum even if you grease the tap and flutes of the drill metal still gets in the cylinder, if you can trust your judgement enough it helps to keep the piston at top dead center, metal filings just go on the top of the piston. I only suggest that if you KNOW you aren't going to drill into the piston. I've done literally hundreds of 4.6 5.4 and 6.8 2 valve spark plug helicoil/time serts. Even on a few 3.0 V6s. The only way to ensure they work properly is to make sure the threads are very clean, apply a good coating of red thread lock to the helicoil going into the head. forgot the number but I've used it for 6.0-7.3 fuel injector cups as well. It's a high temp rated, cherry like odor. On the collar very top of the coil will be a flat spot (at least the ones I've used do) I bottomed the time serts/helicoils then took a tine punch with a point and gave a good whack in 4 spots around that collar. 1 every 90 degrees.

 

Heli-Coil brand thread repair kits, installed correctly, (key words here) are a great way to attend to a buggered spark plug hole.
Certainly best done off the bike to avoid any aluminum debris from going inside the engine.
We actually have several thousands of dollars invested in the proper tooling, and Heli-Coil inserts for the repair of both SAE, and Metric threads, to include Full-Torque Permanent Thread Repair kits as well, primarily used for pulled engine cases studs.
Scott

 

NAPA has a complete repair kit. It includes the tap, the insert and the tool to seat the insert. I've stuffed a wad of cotton down into the cylinder. That way anything slips off the greased tap will get caught up in the cotton and pulled back out of the hole. Never had an issue.

 

I wouldn't use a heli coil for spark plug hole repair,use a 1 piece insert.dont repair it on the bike either

 

the kit. From NAPA works great. A friend just did a 1981 evo and it was easy.

 

When I was in High School the auto shop had a 72 Chevy Nova That had a 500 HP small block. In my haste to chang spark plugs I stripped one of the holes in the head. The instructor and I used a helicoil to repair it and it was fine. So in my own opinion a heli coil would be fine for the job!

Go Philomath High! At the time I ws there we were the fastest high school car in the state of Oregon.

 

When performing contract machine work for McDonnell-Douglas Aircraft, when living near the St. Louis metro area many years ago, the drawings would call out and state Mil-Spec part # so and so, Heli-Coil brand thread insert to be installed at the point of the initial manufacturing of the aluminum part(s).
Used them prior to that, and have been using them ever since.
Scott

 

Heli-Coil are an excellent repair option ... Here is an alternative which might be easier for the novice ... http://www.timesert.com/

 

Quite the kit, if it works on an `81 Evo...

(I know it was a typo but I had to have some fun...)

I would prefer to remove the head, but if done on the engine, consider directing compressed air into the combustion chamber via the exhaust port, that may keep any debris from entering the combustion chamber.