[AT] Stripped threads in alum head

[charles bridges]

Thanks for the replies!!!  Now, at least I know it is called an alignment 
pin.
I'll get back on it in the morning and see what happens.

Thanks
Charles


----- Original Message ----- 
From: "Steve W." <falcon at telenet.net>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Monday, November 30, 2009 6:40 PM
Subject: Re: [AT] Stripped threads in alum head


> charles bridges wrote:
>>   I am working on an overhead cam engine and one of the bolts that holds 
>> the
>> cam shaft cap on is stripped.  It is an alum head, and I am trying to fix 
>> it
>> without pulling the head.  We are looking at 150 bucks worth of gaskets 
>> and
>> a lot of work to pull the heads.
>>
>> The are two steel sleeves imbedded in the top of the head where the cam
>> shaft cap bolts go.  Looks like they are about a 1/4" down in the head 
>> and
>> protude about a 1/4" above, which lets them go about that far up in the
>> camshaft cap.  The drill bit or tap for the helicoil will not go through 
>> the
>> steel sleeve.  How do you get them out to drill and tap the hole out.
>>
>> The camshaft caps take 8mm bolts and of course a 8mm tap will go through 
>> the
>> sleeve.  I need to drill the hole bigger in order to tap it for a 
>> helicoil.
>>
>>
>>
>> Any suggestions will be appreciated.
>>
>> Charles
>>
>> _______________________________________________
>> AT mailing list
>> http://www.antique-tractor.com/mailman/listinfo/at
>>
>>
>
> Well you could pull the alignment dowel out BUT since those are usually
> installed and then the bore is finished you could move it enough to mess
> up the alignment.
>
> As such I would probably run a GOOD 8mm bottoming tap into the hole.
> Make sure you get good threads to the bottom of the current hole. Then
> clean it out VERY VERY well. Now go find an 8MM hardened stud that will
> thread all the way into the hole and leave enough for a nut and hardened
> washer on top.
>
> Coat the stud with Loctite Form-A-Thread.
> Since you are installing the stud to stay you don't need to use the
> release agent. The material will form a thread AND lock the stud in
> place. This stuff can take 45 ft/pounds of torque on an 8mm size bolt.
> That is assuming NO original threads.
>
> I have used this stuff a few times to repair threads in various items
> and other than one failure on my part when I didn't coat the bolt with
> enough release agent and had to redo the repair, It has held up great.
>
> Kit runs about 15 bucks.
>
>
> -- 
> Steve W.
>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at