I agree completely with Greg.
I never had a problem with the Kas cams, including the one that he ground
for me on the last known blank from the Triumph parts system.
I had two cam grinders brush off the information about the two diameters,
and lost three cams over the years.
The most frustrating one broke in front of the gear in T3 at the old
Laguna; if only the rotor had stopped pointing to the #1 plug, the crank
trigger
might have made it to the top of the hill on the last lap of the last
season race, as the front two lobes still worked; it cost the divisional title.
The worst was one that broke in two places, and allowed the front part of
the cam to fall down into the crank.
I installed and closely watched the cam bearings, and polished the radii on
both sides of the gear, and magged the cam at least once a year.
Hardy
In a message dated 10/4/2009 9:06:04 A.M. Pacific Daylight Time,
fot-request@autox.team.net writes:
From: "Greg Solow" <gregmogdoc@surfnetusa.com>
Subject: Re: [Fot] Survey: TR3-4 camshaft breakage
To: "ofbracing" <ofbracing@nefcom.net>, "'Bob Adams'"
I have never experienced any camshaft breakage, but in a reprint of an
article from the English magazine Autocar from April 8, 1955 excessive
camshaft bending in the area of the oil pump drive gear is mentioned. And
this was with early light springs but continuous use over 5,000 rpm. to
cure
the problems the front part only of the camshaft was increased in diameter
by 1/8". Remember, the span of support in the front of the engine is twice
as large as in the rear half. The drive gear has replaced the bearing that
would be expected in this location.
I believe that the shaft diameter should not be reduced below its
original as cast diameter for this reason. If a cam grind has so much lift
or duration that the shaft diameter has to be reduced to accommodate a
small
base circle, then the lobes need to be welded up or a new cam blank with
large enough lobes should be used. The new cam blank should be checked to
make sure the front part of the shaft is 1/8" larger than the rear part.
it
should also be the same minimum size as the original shaft.......
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