I have never seen any manuals or aftermarket publications that disclose
metals specs for Triumph motors. That's really too bad--there's an amazing
book for Vincent Owners called "Know Thy Beast" that details virtually
every important part on the bike and how to either restore it to spec or
make it from better materials. All the more amazing because Vincents were
a "no expense spared" kind of machine to begin with.
That said, there's lots of discussion about proper lifter hardness on the
web, and I'm sure if any of the aftermarket folks wanted to know what
hardness a lifter should be the cam guys could easily tell them (and what
the base metal should be--I'd bet that flaking is not only a function of
too hard a surface, but also too weak a metal under the surface).
However, in all my reading and research on the web, I have never seen
anyone recommend a lifter hardness less than 50. In fact most specify more
than 52 and up to 60. Cams in general are flame-hardened cast iron and
have a hardness range of 48 to 55. Makes some kind of sense I guess. It
seems like the lifter needs to be a little harder than the cam.
I've always been told that the biggest problem with using old lifters with
a new cam is that there's a good change they won't rotate. Some of the
links below seem to confirm that.
I know we can't go to roller rockers in most vintage organizations, but
I've seen little about roller lifters. I suspect people were using them in
the early sixties--they've been in existence since well before WWII.
http://66.96.130.106/archives/2002/05/camfailure/index.shtml
http://www.mgbmga.com/tech/mgb7.htm
http://www.geneberg.com/vlvtrnpg6.htm
-----Original Message-----
From: Henry Frye [mailto:thefryes@iconn.net]
Sent: Monday, September 09, 2002 9:22 AM
To: TeriAnn Wakeman; FOT
Subject: RE: Lifter Hardness
At 09:16 AM 9/9/2002 -0700, TeriAnn Wakeman wrote:
>If anyone has any REAL factory data on hardness specs for TR lifters
>Moss
>would love to get a copy. THey want to know how hard is enough for good
>reliability and where hardness might start causing flaking under use.
Just a thought, I would say take one of the GT40 lifters from Ken, get it
tested, and have them make them to THAT spec...
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