Hi Jim!
I sent a post about this topic on April 25, asking for comments about
influence of these clearances on ignition timing, distributor gear life and
valve train lash.
Bearing clearance is not mentioned in the Manual (at least in the TR2/3
Manual) and I understand it can be quite important for a proper cam and
ignition timing, and these figures are nowhere given or explained.
There are different clearances for the front bearing (the one bolted in) and
the ones inside the blocked (pressed in, make sure you do not file the slot
in the bearings to make ingress easier, they are quite a tight difficult
press fit but make the right clearance).
Clearance bearing #1= 0.00275'' to 0.0047'', Clearance bearings #2-3-4=
.002'' to .0035''
End float min .003'' up to .0075''
I found these figures in David Vizard, Tuning Triumphs over 1300cc,
published 1973, page 32 (NLA of course, found it on Amazon marketplace for a
price).
Vizard recommends to go for the absolute minimum clearance and end float, in
order to affect ignition timing as little as possible.
Apparently end float clearance has quite an impact on ignition timing.
Larry, what about impact on cam timing?
Any comment of Mr Kastner about the comp dept practices at the time?
Cheers !
Alex Camoletti
TR3A 1959
-----Message d'origine-----
De : fot-bounces@autox.team.net [mailto:fot-bounces@autox.team.net] De la
part de Larry Young
Envoyi : mercredi 1 juin 2011 17:52
@ : fot@autox.team.net
Objet : Re: [Fot] TR4 camshaft bearings & clearances
Jim,
Triumph listed cam bearing clearances as 0.0028 to 0.0047 with a wear limit
of 0.0059. You probably want to be toward the lose side for racing, but you
don't want to bleed off too much oil pressure and starve the rockers.
Larry
On 5/30/2011 1:03 PM, Jim Gray wrote:
> FoT,
>
> I can't seem to locate much information on TR-4 cam bearings. I'm sure
> many would appreciate
>
> any input on the following topics. I'm seeing some wear on my cam and
> bearings that needs to be addressed
>
> now.
>
> Questions are as follows;
>
> What are racing clearances for front bearing.
>
> What are racing clearances for the other three bearings.
>
> Does anyone use friction reducing coatings on their cam bearings.
>
> Cam thrust..any info.
>
> Cam bearing type& manufacture.
>
> Any hot tips for cam bearings and overall longevity.
>
>
>
> Thanks for the input as always,
>
>
>
> jim g
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