Peter---Your quest for "a more powerful camshaft" can't be answered
accurately, as stated. One would have to know what your goals are for
this particular engine. If it is now "stock" and producing about 105 HP,
what is the horsepower figure you are looking to achieve?
I'm not trying to be difficult here. One of the best sources for
improving the power for the TR6 is still the "Competition Preparation
Manual" as written by Kas Kastner. (You can get a copy from any of the
Big Three parts suppliers.) This short, but informative booklet shows
power curves and charts comparing several different changes to the
engine. I suggest this as a good starting place for looking for a cam,
or other modifications that can improve both the power AND handling of
the six.
To answer you question of identifying the cam that is now in your
engine...You can get close to finding these specs without compete
disassembly, but it's not easy. It would mean one would have to measure
the "lift" of the valve, using a dial indicator at the pushrod lifter.
For duration, it would be necessary to connect a degree wheel on the
crank pulley to see how long the valve is in the open phase. More of the
same with overlap. I think by now you see that it might be easier to
take off the front cover and just pull the cam out to do (measure) it
right. There's a little more to it than this, but figure on two days to
remove and re-install the cam of your choice. Follow a good manual here,
for proceedure.
This is not a particularly difficult job to do, so far as the changing
out of a cam. It can get more complicated when trying to readjust the
rest of the engine to compliment the cam change. I do not recommend such
a change if you still have to get this car to comply with any "Smog"
tests, unless you are willing to do some under-the-table shenanigans.
The payback for installing a performance cam will change the character
of the engine. Usually, one will lose some low end power (below 2500
rpms) for a giant boost from mid-range to red line. The loss at low end
can be partially retrieved with increases in compression ratio, and the
lightening of revolving parts.
For a larger selection of camshafts, you can look at what TriumphTune
has to offer. They have some that improve power without giving an "idle"
that's difficult to live with.
Dick Taylor
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