Hi Jerry, I'm about to use Moss Motors supplied 89mm liners. For years we've
used standard liners, milled the head for 10:1 and higher street use. Carefully
removing the lip on the head around the intake valve and notching and indexing
each liner to match material removed from the cylinder head shrouding. Using
89mm liners (bigger bore) you will remove less material from the head to raise
compression. If liner projection is correct we've used the steel shim head
gasket BPNW have the correct gasket, be conservative in removing material. The
heagasket also needs to be trimmed to compensate for material removed from the
liner/intake port shroudind on the head. In modifying the head gasket you do
not want it to "hang into" the combustion chamber or you will get detionation
and gasket damage. Finally carefully use contact cement and glue a single
strand of .012" Copper wire into the groove that is around the circumference of
each cylinder of the gasket. I think I have pictures or can take some this
weekend. We've done this for many years on lots of TR and Morgan race engines
and have had great success and no failures.?
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Jerry Van Vlack via Fot <fot at
autox.team.net> Date: 9/20/17 1:15 PM (GMT-08:00) To: asg123 at
centurylink.net, triumphs at autox.team.net Cc: 'Friends of Triumph' <fot at
autox.team.net> Subject: Re: [Fot] [TR] TR4A head gasket, 87? mm cylinders
I?m interested in the responses too as I recently suffered a head gasket
failure around the intake shroud of #4 using a 91 mm Cometic (very similar to
the Lucas new improved one) In my case the head is milled .090 using 87 mm
liners. The old Payen style lasted 30 or more years until I did a valve job 4
years ago. The Cometic lasted 4 years until it failed. I?ve discovered some
extenuating circumstances which may have caused my failure but I am interested
in the responses, especially from those who have moved up to the 89 mm liners.
How have you sealed the 89?s and or is it too early to report results? Also
please indicate if you?ve milled the head and by how much.
?
I?ve discussed this with some very reputable Triumph performance folks in
the last week and gotten some good input but would like to broaden the
discussion.? Once we see some responses I?ll be pleased to share what I?ve
discovered. Those who I?ve already discussed this with can chime in or not, I
will include your advice but not who you are unless I have your permission. But
I?d like to hear some input from others before I do that.
?
Regards,
?
Jerry Van Vlack aka JVV
66 TR4A
?
?
?
From: asg123 at centurylink.net
Sent: Wednesday, September 20, 2017 1:51 PM
To: triumphs at autox.team.net
Subject: [TR] TR4A head gasket, 87 mm cylinders
?
I have asked a similar question before but my mechanic and I are still
undecided which rabbit hole to enter
Does anyone have experience with which head gaskets hold up best against
blowing out around the combustion chambers?? I see the stainless steel
composite gaskets which claim to be the best.? But, some people, including
the tech support at BPNW, say that the OE copper gasket by Payen withstands
high
compression the best.? How does the German made Payen copper gasket hold up
compared to the Lucas OE type copper gasket??? We had an OE copper
head gasket blow out between cylinders #1 and #2 after only a few thousand
miles. It was using 93 octane gas with the timing retarded a couple degrees to
keep down spark knock, but it still dieseled on when we tried to shut it
off.?? A solid copper head gasket from Gasket Works custom milled to
drop the compression to 130psi fixed the spark knock and dieseling, but we had
chronic problems with the oil and water weeping into each other no matter what
sealants we tried. As always thanks for your responses.? Arnold
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