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How do I?

hb2u's Avatar

Join Date: Dec 2000
Posts: 117

03-21-03, 12:51 PM   #1  
How do I?

I have a couple of small engines with stripped screws/bolts. (cursed hand me down equipment) How do I fix these?

One in particular is a head bolt on a 7.5 hp tecumseh engine with an L shaped setup (valves offset from the piston).

I replaced the head gasket cause I thought it was bad and causing an oil leak, but when I put all the bolts back in I coudn't torque one down properly, so it's stripped. The problem is that the HOLE is stripped, not the bolt. How do I repair the threads - do I need to buy a larger diameter bolt once I repair the threads - where the heck do I get a larger diameter bolt?

I have seen tapping sets before but never got any hands on actual experience.

Please help. (and describe as much as possible including what the tap sizes mean, where to get the equipment and the parts I'll need afterward etc.)

Thanks a bunch.

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slumlordfrank's Avatar

Join Date: Mar 2003
Posts: 702

03-21-03, 01:23 PM   #2  
stripped threads

You could try a Heli-Coil repair, auto parts store should have it. Essentially you drill the hole slightly larger, then insert the "coil". The coil is the new threads in the engine.
I'm not sure what you mean by the sizes on the taps, but from simplest to most complex they are; Diameter and thread pitch, such as 3/8-16 is 3/8" diameter and 16 threads per inch. 12 X 1.5 means 12 mm diameter and 1.5 mm from thread crest to thread crest. The other numbers refer to "class of fit, ie; how tight the fit is between the bolt and nut, or in your case between the bolt and casting.
I'm sure some of the guys still in the trade will add to this.
Let us know how it comes out.

Tcumcman's Avatar
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03-21-03, 07:49 PM   #3  
Thread Repair

Heli-Coils work GREAT....as long as they are
installed correctly. FOLLOW INSTRUCTIONS and
you should be OK with that as a repair.


cheese's Avatar
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Join Date: Jul 2001
Posts: 16,569

03-22-03, 12:49 AM   #4  
I agree...Heli-coils will do the job when installed properly. I have seen them at autozone. Make sure you get the proper size....take your bolt to match it to the set.

"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

hb2u's Avatar

Join Date: Dec 2000
Posts: 117

03-24-03, 04:56 AM   #5  

Thanks for the info. I'll get to the auto parts store this week and see how it goes.

I'll post my results in a week or so.

Thanks again.

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