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The larger diameter is to have the fire ring outside the intake valve
pocket in the head. I run smaller diameter pistons than 91mm
too. The 88 mm gasket has the fire ring inside the valve pocket and
that's instant leak.<br><br>
Regards, Tony<br><br>
At 10:44 AM 4/4/2017, Bill Beecher wrote:<br>
<blockquote type=cite class=cite cite="">I have 86mn pistons, do I need a
91mm to outskirt the liners? Is Comtic the best head gasket for
aluminum heads?<br><br>
Straightedge show no sign of warpage, and no visible damage any where now
that it is cleaned. <br><br>
Tom, how hot and how long in the oven? Can I just sneak it in under
Momma's biskets?<br><br>
Many thanks to all,<br><br>
Bill<br><br>
<br>
Sent from my Altair 8800<br><br>
On Apr 4, 2017, at 10:34 AM, Tony Drews
<<a href="mailto:tony@tonydrews.com">tony@tonydrews.com</a>>
wrote:<br><br>
Definitely has the symptoms of blown head gasket. I've had much
better luck with compressible gaskets than solid ones. Solid ones
need liner protrusion to be PERFECT.<br><br>
The Aluminum heads have the intake valves unshrouded like you'd get if
you milled a stock head. My latest head gaskets have been Cometic
ones. On line their store lists 88 mm gaskets but if you call you
can get a 91 mm gasket. This is almost large enough diameter to
keep the fire ring completely out of the combustion chamber. Steve
Yott was having some 92 mm ones made of a similar design.<br><br>
I can't comment much on the head itself - I know one of my racing
competitors ran an aluminum head for a few years and had constant head
gasket problems so went back to iron at some point.<br><br>
Regards, Tony<br><br>
At 06:53 PM 4/3/2017, Bill Beecher wrote:<br>
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<font face="Calibri" size=2>Happy Monday List,<br>
<br>
Have had a problem with some water up in the rocker area of the TR3(TR4A
Motor) ever since I bought it last year. Just now getting to a
point where I can pull the head and see if I can see what the issue
is. Below are my observations:<br>
1. Did not know it was an aluminum head until today, re-torqued it last
year when I first saw this problem at 95lbs. Learned today it
should be 70lbs.<br>
2. Runs great, compression checks out good at 150-55 across all.
But after getting up to highway speeds then coming back to town it
quickly overheats and blows the water past the rad cap.<br>
3. Cannot see any damage to the solid copper head gasket. Is this
the right type gasket for an aluminum head?<br>
4. Cannot see any damage to the head, how do you check an aluminum
head? I would think that magnaflux would not work here.<br>
5. Drained and checked the oil last fall, no water present in the
case.<br>
<br>
Any suggestions from the collective wisdom would be greatly appreciated,
seems this motor was intended for some level of performance as it also
has Moss�s roller rockers. <br>
<br>
Many thinks to all,<br>
<br>
Bill B<br>
TS30800L<br>
<br>
<br>
<br>
<br>
</font><br>
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