Not that I'm trying to tell you how to suck eggs, but the primary reasons for
using roller rockers are to decrease side thrust on the valve stems, reduce
friction in the valve train (pin bearing in the rocker and a roller) and
reduce reciprocating weight. The only way that translates into higher
horsepower is to take advantage of the opportunities these factors enable. A
lot of speed equipment is sold to people with no plan to take advantage of the
factors the equipment was invented to improve. If your cam won't benefit from
a higher rocker ratio then you won't gain anything from it. If you're not
prepared to experiment with shorter intake valve guides to improve flow then
the reduced side thrust won't give more horsepower, just better guide
wear--which none of us care about.
You can get a lot of horsepower from roller rockers, but not by bolting them
on.
-----Original Message-----
From: fot-bounces+billb=bnj.com@autox.team.net on behalf of Allen Washatko
Sent: Wed 12/26/2007 2:20 PM
To: Friends of Triumph
Subject: [Fot] Roller Rockers
FoT,
I need some input regarding the use of roller rockers on a race
prepared TR6. If you are running a cam with .500 lift and 300 degrees
duration, does the use of a higher ration roller rocker (1.65) really
add that much more power? This is assuming that the head is well ported
and you are running the largest intake/exhaust valves that fit in the
head. I was just made aware of some engine testing recently that
indicated that there was only a 2 h.p. gain by using roller rockers
with the above modifications. It also indicated that the increased
ratio caused more wear on the cam, tappets, etc. The logic as presented
seems to be that you can only draw so much flow through the head
before you get diminishing returns. Any thoughts on this?
Allen
Allen & Jody Washatko
1971 TR6 - Number 6
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