[DeTomaso] Magnaflux cracks - now what?

Jeff Cobb jeffcobb1 at me.com
Wed Nov 9 19:02:56 EST 2016


Larry,
Those crack of course most likely where caused by exhaust system overheating not high coolant temps.
I see these cracks on BMWs and block is still fine—JUST cure your overheating issues!
Block is good as long as cracks are drilled and pinned to stop crack migration, inner water flow hole chamfering will relieve stress edges which helped cause the cracks, that the heat did not change/damage cam/crank line bores/saddles
and that all the head bolt holes are drilled for deep Threadsert insertion.”””NOT HELICOIL”””.

Cryogenic block de-stressing should be an option if you desire to keep this block.
You don’t need crack migration and weak head bolt thread bores.

Take care, 
Jeff Cobb

On Nov 8, 2016, at 2:28 PM, Larry Finch via DeTomaso <detomaso at server.detomasolist.com> wrote:

> All,
> 
> Magnaflux testing of my original block has shown a total of five cracks (LH/RH) out of six possible, as shown in the photo below. Cracks are within the marked white lines. 
> 
> Cracks are from the water jacket to the head bolt threads. No cracks running into cylinders.
> 
> I had taken note that some of the head bolts showed traces of coolant on them when removed, but no signs of any rust on any of them.
> 
> Planned engine build is 383 or 408 hydraulic roller stroker using Scott Cook heads and intake with carburetor.
> 
> Do those cracks mean the original block is now history?
> 
> In 15 years of ownership I have never heard of Cleveland's exhibiting cracks in this manner.
> 
> Seeking the Family's wisdom and advice.
> 
> Thanks,
> 
> Larry
> 
> <image1.JPG>
> 
> Sent from me using a magic, handheld electronic gizmo. _______________________________________________
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