Stripped threads in block

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corkmodelt
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First Name: Noel
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Stripped threads in block

Post by corkmodelt » Thu Apr 04, 2019 3:53 pm

Hi

I have a problem with stripped threads in one of the bolt holes in the block & I was reading in older threads on repairing the problem.
Some mentioned Heli coils & in another discussion the was talk about a "Stevens" tool/kits.

Any advice on whats best to do

Many thanks
Noel


Humblej
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Re: Stripped threads in block

Post by Humblej » Thu Apr 04, 2019 4:15 pm

Helicoils, easy to do, inexpensive, readily available. Stevens thread repair requires a larger hole than helicoil, and are not easily obtained. I have a Stevens set but never use it and dont recomend it.


Topic author
corkmodelt
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Last Name: O'Keeffe
Location: Co Cork , Ireland

Re: Stripped threads in block

Post by corkmodelt » Thu Apr 04, 2019 5:01 pm

Thanks for reply,

Is this what I need
https://www.ebay.co.uk/itm/7-16-UNF-V-C ... XQ-KRRiRmJ


Scott_Conger
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Re: Stripped threads in block

Post by Scott_Conger » Thu Apr 04, 2019 6:28 pm

Since you're looking at 7/16, this tells me you're looking at a headbolt repair, right? If so, you want 7/16-14 UNC, not UNF. Your link is going to 7/16-20 UNF, which you definitely do NOT want.

Something like this is what you want: https://www.ebay.co.uk/itm/Helicoil-552 ... SwepZXTb9B

The head can be installed with several bolts, and the 29/64 drill used to clearance drill for the helicoil tap, just fits the head bolt clearance hole, to pilot the drill square and in the proper place...remove head to tap.

Otherwise, nearly every other bolt on the engine is a 3/8-24
Scott Conger

Full Flow Float Valves - deliver fuel like Henry intended!

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kelly mt
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Re: Stripped threads in block

Post by kelly mt » Thu Apr 04, 2019 7:39 pm

I used this thread repair on my last problem. I like them better than Helicoils. One caution, one experienced guy on here has said to be careful as some thread holes are close to the water jacket. Ez-Lok from McMaster Car.
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Dan Hatch
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Re: Stripped threads in block

Post by Dan Hatch » Thu Apr 04, 2019 7:46 pm

Here is a link to the stevens tool repro. Dan
http://www.mtfca.com/discus/messages/50 ... 1425415180

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jsaylor
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Re: Stripped threads in block

Post by jsaylor » Fri Apr 05, 2019 12:03 pm

HeliCoils work fine. Easy to do. I put several in my 21 block some 50 years ago and still holding fine today.


Topic author
corkmodelt
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Re: Stripped threads in block

Post by corkmodelt » Fri Apr 05, 2019 8:11 pm

Thanks for all the replies, must get working on it now.

Regards

Noel


Graybeard77
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Re: Stripped threads in block

Post by Graybeard77 » Tue Apr 09, 2019 8:15 pm

I just finished putting coil in one of my block head bolt holes today. I put the new Z head on and torqued the bolts . It worked just fine. Will put the motor back in tomorrow.

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