At 12:52 AM 4/30/96 -0400, you wrote:
>Don-
>You ask about cam specs...
>
>Factory specs say Inlet Exhaust Lift
> 35-65 65-35 .250"
>
>Since this is a factory reference I do not know at what lift they take their
>measurements, so as a comparison please note a carburated model TR6 specs,
>again from the factory.
>
> Inlet Exhaust Lift
> 18-58 58-18 .240"
>
>Please note that there is a major difference in specs. The injected cars
>could run what would be a fairly hot street cam for a carburetted car, but
>still idle quite well due to the injection.
>
>Be very careful if you specify specs for the grinder, as most all
>specs you will see are from emasculated US cars. You will probably be better
>off showing the grinder what you have and asking his opinion how to increase
>the HP. (IMHO, I would increase the lift somewhat and leave the
>opening/closing points where they are).
>
>To measure any lobe wear, simply use a caliper and check total height of each
>lobe, measuring from the heel of the cam to the lobe. (Basically, just put a
>caliper on each lobe across the highest and lowest points where the lifter
>rubs on it).They should all be the same measurement, if not, that is how much
>wear you have.
>
>If you modify your cam specs, please check the valve springs very closely in
>regards to coil bind. Also ask your grinder if he thinks you will need
>stronger springs, higher lift=faster lift rates=need for
>stronger springs.
>
>The cam kit offered by many parts houses (Vicky Brit, Moss TRF etc etc) is
>intended for a US engine, but is probably a milder cam than what you have in
>your car now. Try to contact Triumphtune in England as they will have more
>knowlege of the PI cam, and what a wilder setup for that engine would be.
>
> The Car Curmudgeon
> Nick
>
>
>
Pardon me,
if I'm intruding, but I have a copy of a "Competition Preparation
Manual" published by the Triumph Competitions Department of BLM sometime in
the mid-70's that applies to the TR6. The camshaft portion of this manual
mentions that at the time there were two camshafts available for the TR6:
the S-2 cam, Part No. V578 and the S-4 cam, Part No. V579.
The following specifications were also listed:
For the S-2 Camshaft:
Inlet: opens 31 BTDC closes 71 ABDC
Exhaust: opens 71 BBDC closes 31 ATDC
Duration 282 Lift .405"
Checking clearance at camshaft -- .013"
Operating clearance at valve hot -- .016"
For the S-4 Camshaft:
Inlet: opens 42 BTDC closes 71 ABDC
Exhaust: opens 71 BBDC closes 42 ATDC
Duration 293 Lift .410"
Checking clearance at camshaft -- .013"
Operating clearance at valve hot -- .020"
The S-2 cam was recommended for street use with the following modifications;
10.0 to 1 C.R., velocity stacks, and a valve grind.
I hope this information may be of use to you.
Cheers, JohnnyB
--
jhinman@accucomm.com
'69 TR6, 79' Scout
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