Thanks to everyone who offered suggestions!
Here's the plan for repair:
First, the head will get magnafluxed to determine if it has any other cracks.
If the head passes that test, the repair to the two troubling cracks will be
done by "stitching".
My machinist has a fair amount of experience with this process which involves
drilling and tapping a series of holes along the centerline of the entire
crack. This will be done one at a time, starting with the end closest to the
combustion chamber.
The hole gets tapped using a special tap similar to a pipe thread tap and the
special (cast iron) tapered bolt gets threaded in and cut off near the head
surface, to be made even with the surface when the final machining is done.
The holes get drilled so that each successive bolt has some contact with the
preceding bolt near the head surface, and each bolt gets coated with a special
epoxy before being threaded in.
Wherever possible, the bolts will be installed so that they bottom out, and
act as "stakes" just as Kas details in his book. Additional stakes will also
be installed away from the crack in an effort to stop any further collapse of
this already thin (shaved about .150") head in this area and hopefully add
even more stability to the repair.
We'll see how it turns out.
Thanks again,
Rich Rock
________________________________
From: michael
Sent: 12/24/2014 3:39 PM
To: Doug Mitchell; Tony Drews; fot@autox.team.net
Subject: Re: [Fot] TR head cracks
Years ago, I remember taking a TR3 head to a place in Long Island City, New
York called Cool Weld. Using a process called "cold welding" they patched a
combustion chamber. This wasn't a crack, it was a hole but it worked on
cracks
as well.
That was my back-up head and it worked fine for several races and also for
the
guy who bought the car.
Mike Cook
> Date: Wed, 24 Dec 2014 13:03:52 -0500
> From: dmitchel@sbcglobal.net
> To: tony@tonydrews.com; fot@autox.team.net
> Subject: Re: [Fot] TR head cracks
>
> You might check into an old-school technique of cold stitching. Not sure if
it works on a head, but have seen it done on blocks. Not cheap and intensive
work, but it can recover a block.
>
>
> Doug
> dmitchel@sbcglobal.net
> Sent from my mobile phone
>
> -------- Original message --------
> From: Tony Drews <tony@tonydrews.com>
> Date: 12/24/2014 12:27 PM (GMT-05:00)
> To: fot@autox.team.net
> Subject: Re: [Fot] TR head cracks
>
> I received a picture of the head - the crack is to the point where if
> it grows any further there will be definite sealing issues on #2 and
> probably #3.B I like this suggestion - a hole to stop the propagation
> and silver solder to seal it back up.B I'll have to remember that one!
>
> When I went through the "cracked head" issue (mine wasn't
> repairable), someone suggested "stitching" which is a series of
> threaded plugs run through the crack.B That's the only other fix that
> comes to mind.
>
> Cheers, Tony Drews
>
> At 05:53 AM 12/24/2014, MadMarx wrote:
> >You can stop the crack with a hole at its end and solder the crack with
> >silver solder.
> >Seems to work fine with a good success rate.
> >
> >Cheers
> >Chris
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