My experience reflects what Randall says. I had a machine shop
magnaflux 3 TR3 heads from a local collector before buying one from him.
3 for 3 with cracks all had the standard crack in the water jacket web
between #2 & 3, one had a number of cracks the terminal one running
from the exhaust seat along the the exhaust port too far to be repaired
with new seats. The other 2 heads had cracks between exhaust and intake
seats in #3. Both were repairable with new seats. All the cracks found
with magna fluxing were undetectable with the naked eye.
Doug Hamilton
1960 Triumph TR3A
1963 Fiat Cabriolet
1967 Chev C/10
>Date: Wed, 28 Apr 2004 16:38:27 -0700
>From: "Randall Young" <ryoung@navcomtech.com>
>Subject: RE: piston & liner (update)
>
>
>
>>> It was...a cracked head!! ARRRRGGGGHHHH...magnaflux showed
>>> deep crack between intake and exhaust valve on cylinder #4, extended
>>> from bottom of head up through the exhaust valve seat...
>>
>>
>
>Bill, the part that puzzles me is that, if the crack was big enough to leak
>that much, it should have been clearly visible without magnafluxing.
>Certainly if it were leaking at the exhaust valve, you would see a gouge at
>the seat like a cutting torch had been used on it. And unless it was
>leaking combustion gases out of the combustion chamber (which do bear a
>strong resemblance to a cutting torch) ... it could not affect the
>compression.
>
>I believe cracks are actually fairly common in TRactor motor heads, it's
>just that the majority of them go undetected. ISTR someone reported a few
>years back that they had bought 6 heads "removed from running engines" and
>found cracks in 5 of them ...
>
>Anyway, good luck with your new one.
>
>Randall
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