Thanks Micheal. I thought it was something along those lines.
Michael D. Porter wrote:
> Roger Helman wrote:
> >
> > Since we are talking about valve lash. I just installed a new cam from
> > TRF about 1 month ago in my TR-6. TRF said the intake lash is .018 and the
> > exhaust is .020 for the cam. Does anyone know the purpose of increasing the
> > valve lash from .010? Does it effect performance? Inquiring minds want to
> > know.
> >
> > BTW the cam is supposed to be the equivalent of the S2 grind.
>
> Roger--the lash settings are generally increased on performance cams for
> a couple of reasons. First, it's presumed that the engine is going to be
> run at higher speeds and greater power output, so there would be some
> expected increase in temperature over normal, and the valves and
> pushrods would naturally grow a bit more. But the principal reason is
> the grind itself. The profile of the lobes is different, and the ramp on
> the lobe gets steeper as the duration increases. If the lash were left
> unchanged, this steeper ramp might cause greater accelerations of the
> valve gear than would be advisable, resulting in increased wear and
> possible valve gear breakage.
>
> Cheers.
>
> --
> My other Triumph runs, but....
--
Roger Helman 71 TR6 CC67866L
Digimation Inc. http://deepthought.digimation.com/rogerh/
New Orleans La.
www.digimation.com
Voice. 504.468.7898
Fax. 504.468.5494
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