Well, I did go with the 87mm upgrade when I rebuilt my 4a engine last year,
but not sure it was worth the extra $$$. It is a bit self defeating - the
larger the piston, the more mass; the more mass, the less revs. And we all
know revs = fun! Ever see the inside of a Ferrari engine? The pistons are
about 50mm, but they get some serious revs and HP out of those things.
'course there's lots of other stuff that helps too.
Anyway, I'd say if I were to do it over again I'd spend the money else
where... like maybe overdrive! :-)
I'm sure Randall will have some good words of wisdom on this subject...
Brian
'67 TR4a
Just won 1st place in my class at the Portland All British Field Meet! Time
to sell???
------------------------------
Message: 5
Date: Sat, 6 Sep 2008 15:31:43 -0700 (PDT)
From: Pat Caffrey <pcaffrey@deltacollege.edu>
Subject: [TR] TR4A Piston Upgrade
To: triumphs@autox.team.net
Message-ID:
<28406311.480721220740303817.JavaMail.root@hermes.deltacollege.edu>
Content-Type: text/plain; charset="us-ascii"
Hello,
I'm having an engine rebuild on my 1967 TR4A and am considering upgrading
the pistons to either 87mm or 89mm. The car is strictly for street driving.
I'd like to get more power out of the engine but fear 89mm may be too much.
Still, 89mm is only 3mm bigger than the stock 86mm pistons. Any thoughts on
which direction I should go? 87mm or 89mm?
Thank you,
Pat
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