.After I posted the inquiry, I did a little more research:
* The Triumphtune manual recommends upgrading
* the TR6 Competition does not (and it is vague on whether they should
be replaced with new stock, or just re-use)
* the local auto machine shop suggested replacement, but were grossed
at the price
* a fellow who has built hot TR6 engines suggested it it a question of
$: if you can afford it, do it.
Decision: I ordered the competition grade con bolts from Moss, and passed
on the comp grade head bolts. The con bolts are obviously more important in
terms of the type of failure, and in my books are much less likely to fail.
Thanks for all your help. Stephen
> ----------
> From: Bill Sanford[SMTP:tvrdude@netzero.net]
> Reply To: Bill Sanford
> Sent: Sunday, February 13, 2000 11:43 AM
> To: Hill, Stephen M EDUC:EX; tvr@autox.team.net
> Subject: Re: TR6 Conrod Bolts
>
> Stephen,
> The two things to consider on uprated bolts are: age and comp. ratio.
> As for age if the bolts have been used a few times: IE been off and on.
> This allows the bolts to stretch and weaken to in extreme cases,
> failure.
> A higher comp. ratio just speeds this detioration up. The con rods
> will see far more stress than main caps.
> The above can be applied to head bolts also.
>
> Good luck
> Bill
>
> "Hill, Stephen M EDUC:EX" wrote:
> >
> > I am gathering bits for warming up the TR6 in my 1972 TVR. My plan is
> > triple Webers, increased CR, flowed heads, lightened flywheel, lightened
> > valve gear, cam etc. I hope to go from 105hp (detoxed US engine) to
> about
> > 160 hp.
> >
> > Moss sells a competition set of head bolts and con rod bolts, costing
> about
> > $200 US on sale. Is this recommended? Essential? Optional? A waste
> of
> > cash? My instincts is the head bolts are unnecessary, and the con rods
> > bolts are more important, but how important I don't know. However, if
> one
> > is uprating conrod bolts, why not main bearing cap bolts (which don't
> seem
> > to be available. I would appreciate any feedback from the TVRheads on
> the
> > list.
> >
> > Stephen
>
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