All the sidescreen TR's left the factory with 4 psi radiator caps. I am on
my second or third one since 1958. The story is that at 4 psi, you won't
(or can't) separate the tubes from the fins in a radiator, over the normal
life of a rad that was made in the 1950's. But if you blow a head gasket
between the combustion chamber and the water jacket, you can get very high
pressures in the rad. Sur the cap will blow at 4 psi (or 15 psi), but there
will be some damage to the tubes in the rad. I don't care to say how high
but maybe a lot more than 4 psi or 15 psi. This will bulge the tubes in the
rad and the tubes which are normally kind of a flat oval will tend to want
to become round. If they do, the cooling fins are no longer in full intimate
contact with the flat (now a round) tube and the heat can't be transferred
from the tube to the fins, so the fins stay cool with the air rushing
between them and the water in the tubes stay hot and keeps getting hotter
and hotter.
Don+ Elliott, 1958 TR3A, Montreal, Canada
----- Original Message -----
From: <BillDentin@aol.com>
To: <cartravel@pobox.com>
Cc: <fot@autox.team.net>
Sent: Wednesday, March 05, 2003 4:12 PM
Subject: Re: Head Cooling Problems
> In a message dated 03/05/2003 2:14:08 PM Central Standard Time,
> cartravel@pobox.com writes:
>
>
> > However, it seems to
> > me you'd
> > be better off using a higher pressure cap.
> >
>
> My mechanic Kevin and I argue about this. Mike Belfer always wanted to
use a
> 7# radiator cap. None larger! Kevin (old big block chevy guy) wants to
use
> 25#. I think we've been running 15#.
>
> Thoughts?
>
> Bill Dentinger
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