Hugh,
Here are my thoughts on the head.
British Parts NW have the short pushrods if you need them. You need them
if, after milling, you don't have enough adjustment at the rocker arms.
I personally use hardened seats in the exhaust side. The intake seats
are unnecessary unless the head is badly worn at the seats.
I use the cast guides with an additional seal on the guide for oil
control. I believe it is an MGB seal.
The stock valves are adequate for street use, the ss exhaust valve sold
by BPNW is the valve I use for replacement. I would have your machine
shop mic all new valves you purchase, because I have found large
variance in stem diameter in some suppliers replacements.
I like a mild cam in the TR6 motor. Too much cam won't give enough
vacuum at idle to allow use of downdraft carbs (in my experience). I
would NOT spend money on cam bearings unless your block is worn in the
cam bores, you are running high spring pressures, or you don't care how
much you spend. Elgin cams in CA. has a nice grind for TR6, and can
harden the cam for you. I always have one around. The GP3 seems to get
high marks from those that have used it.
The mod that I WOULD recommend is to pin the skimpy thrust washers to
the block. Balancing would be my second choice, and also to clean up the
head with a light grinding to smooth the area around the plug, and any
rough casting flash. The motor will ping less with more advance, and
shut off cleaner.
As far as the bottom end... if you don't see a nice crosshatch in your
bores, yank the pistons, rent a cylinder hone, and freshen up the bores
with new rings. You'll be glad you did. at the same time, you'll change
the rod bearings and inspect the main bearings. If you see copper,
replace them too. It can be done without pulling the engine. I'd also
replace the thrust washers OIL GROOVES TOWARD THE CRANK!!! The Haynes
manual is wrong in the way it depicts this, and is responsible for many
ruined motors IMHO.
One mod I'd like to see is a roller cam follower. That would be a nice
item. Anyone know of a source??
Jim
----- Original Message -----
From: "Hugh Fader" <hfader@usa.net>
To: "6 Pack List (E-mail)" <6pack@autox.team.net>; "Triumph Mailing List
(E-mail)" <triumphs@autox.team.net>
Sent: Monday, February 04, 2002 7:22 PM
Subject: Advice on cylinder head
> Over the weekend I removed the cylinder head from my TR6. The main
reason is
> to replace leaky valve guides. The valve in the suspect cylinder was
crusted
> over with black tar so I'm guessing this is the leaker.
>
> I am looking for some advice on other things to do:
>
> I am considering shaving the head to increase the compression ratio to
> ~9.5:1. This should improve torque slightly at all rpm and give
several %
> HP. There has been some discussion about shorter pushrods or shims
under the
> rocker arm pedestals. Is this an absolute necessity? Can anybody name
a
> supplier for these? Moss only has one pushrod listed.
>
> Hardened valve seats for no-lead. Any opinions? Worth the expense? It
> doesn't look like the valves are receeded but this is just visual.
>
> Stellite exhaust valves? Is this a no-lead upgrade, for racing, or
what?
>
> I toyed with the idea of putting in a longer duration cam. Still only
for
> street use. Just thinking about recovering the HP that the EPA
regulated
> away. As I understand, installing cam bearings is a common upgrade.
Any
> other things to consider? I don't want to get into the bottom end at
this
> time.
>
> The bores feel smooth, can't feel a ridge, compression is good, if I
recall
> correctly oil pressure is about 25 psi at warm idle. Anything I should
> inspect or do while I have the head off?
>
> Can anybody quote costs for head work they have had done recently?
>
> Thanks in advance for sharing your colective wisdom.
>
> Hugh Fader
> 72 TR6
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