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How to Helicoil / Ezlok when threads recessed 2" ?

Hello,

New to this group, sorry if this is off topic. Was working on a Honda aluminum motor. The head bolts are hardened steel 12mmx1.5.

Some metal pulled out of one of the bolt holes when the head was removed. Uh oh. I guess 200K seized them a little bit. Upon reassembly, that bolt pulled out at final torque. Doh!

Big problem: the threads start about 2 inches below the deck surface. Can't reach the threads with my tap or with the helicoil tools.

Timesert makes a kit (the Honda Odyssey kit) that would work, except it costs $400 and is for pro rebuilders. I am a do it yourself hack.

Can anyone recommend what to do in this situation when a helicoil or EZ lok is necessary and the threads are so far down inside?

The motor works fine and would be a shame to have to junk it over such an annoying issue. That's throwaway engineering I guess.

Thanks.

Ryan Underwood

Reply to
Ryan Underwood
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Over the years I've made many an extended or "pulley" tap by taking length of O1, grinding a square on one end, setting it and a tap up in a fixture of vee blocks, and silver soldering the rod and tap together.

I always used a piece of stock that was just larger than the diameter of the tap's shank. I'd drill it so that the tap's shank just started into it, and then silver solder it in place.

Do the same with the insert holder and you should have a clean walk in the park.

Best,

Weyland

Reply to
Weyland

I have made extended taps by taking a piece of stock and drilled and bored it a few thousands under the tap shank size then heat stock cherry red and press the tap shank into the bore and let it cool. You might be able to get it hot enough on a stove. If you don't have a welding kit. Jim

Reply to
Jim Sehr

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I'll second that one. A few years ago, I needed some 24" long #3 robertson bits to drive some 5" wood screws. I silver brazed some

1/4" hex sided bits to some 1/4" crs and it worked very well for > 500 screws driven into wood with a cordless drill.

Clutch

Reply to
clutch

Drill the hole oversize and tap the block for a larger bolt. Assuming there is adequate material it should be OK for that one position. Get it all buttoned up and running and sell the car.

Reply to
daniel peterman

daniel peterman wrote in article ...

Now there's a craftsman-like repair that anybody should be proud of..........

Why shouldn't he just weld the thing together?

Reply to
*

It's actually a motorbike engine; posting was originally to rec.motorcycles.tech, and he wants to keep the bike.

Leon

Reply to
Leon

Well if he needs to drill oversize to put the helicoil or timesert in and the parent material was strong enough to hold a bolt in the first place, then why would a slightly larger hole with a correspondingly larger bolt with a few percent larger total threaded area be a signifigant compromise in strength. If you are worried about the ethics of selling the car soon after, you should notice that I didn't say a thing about not disclosing the repair to the buyer. At some point he is going to sell the car anyway with whatever repair he chooses so what is the difference? Real craftsman use their real names,

Reply to
daniel peterman

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