Exhaust threads stripped

[Anonymous]

Hi everyone,

I need some advice please. I stripped the threads out of the hole for the exhaust flange on my 1982 850L. Number two cylinder, top hole. What is the best repair for this?

[jpaul]

You have two choices. Either drill & tap out to the next largest size, which would probably be a standard size, not metric; or use a heli-coil to maintain the same size bolt.

[Anonymous]

How is a helicoil used? Where do I buy one?

[SqDancerLynn1]

Easiest way is to ?? options
1 drill & tap to next size
2 drill & tap for helicoil of original size
3 drill & tap for a timecert -- sim to helicoil
Just make sure to drill it straight

[jpaul]

Heli-coil inserts (or other brands) can be found at machine tool supply stores. You need to have the proper size drill and tap to do the job. I just had to put heli-coil inserts in two of the exhaust flange bolt holes this past week due to two bolts which broke off when I tried to remove them. I bought a kit which included about 12-15 inserts in 3 different lengths, the proper size drill, tap, and the tool for inserting the heli-coil. I cost me about $50, which is what I paid to have two helicoils installed several years ago when I buggered up the job of torquing down the cam cover bolts on my 1100E. If you doubt your ability to drill the holes straight, it may be worth it to have someone else do the job. It turned out to be relatively easy for me, but I've always been pretty good at visualizing angles.

[ptm]

For more info about Helicoil http://www.emhart.com/products/helicoil.html

You should be able to get them at most auto parts stores or big hardware stores. The kit usually comes with the proper size drill, the special tap and several coils. It's not cheap, but it is an excellect fix.

As mentioned before, it is important to drill the hole straight. You might try making a jig. A block of aluminum or even hardwood an inch or two thick with the proper size hole drilled straight into it (using a drill press) would work. Use the flange for a template. It has to be small enough to sit flat where the exhaust bolt goes. Another way to do it by hand would be to put a long bolt where the other exhaust bolt goes. It will give you a good visual reference you can use to line up your drill in the other hole.

[Anonymous]

Thank you eveyone. I'll let you know how it comes out (goes in?).

Jerry

[Anonymous]

I busted one off when reinstalling my exhaust as well. I had to use a helicoil bought at my local auto supply store. It included the tap and 8 coils and cost me $32. It worked so well, I drilled out all of the exhaust holes and put coils in all of them. Now it's stronger than ever.

Good luck, just make sure you keep account of where the snap off tab goes after you snap it off