Hi Randy,
I think you might find the F cam a bit much for a street car, even a
relatively hot one. It has 300 degrees duration, which will position it's
performance curve pretty high. Combine that with oversize valves and the light
flywheel
and you might find yourself cursing every stoplight and stop & go traffic,
even more than usual. Expect a rough idle and a lot of clutch slipping needed
off the line.
The Kastner "D" cam is 284 degrees is more often recommended for hot
street setup. Even so, keep in mind that cam technology has come a long way
since
Kas tuned 4-cylinder TRs in the early and mid-1960s. Also, tuning for
production class race cars as he was, meant Kas had to work within some
limitations of
the original cam.
There are other factors including lift, symetry, etc., but as a rule of
thumb with a normally aspirated and carbureted 4-cylinder engine you can expect
*approximately* the following "power band" from a cam:
270 degrees... 1500 to 5500 rpm
280 degrees... 2000 to 6000 rpm
290 degrees... 2500 to 6500 rpm
300 degrees... 3000 to 7000 rpm
310 degrees... 3500 to 7500 rpm
TRs came stock with a 244 degree cam, providing good torque and low end
"grunt" for decent street manners.
Many of the "street performance" cams currently offered by various
vendors are around 260 to 270 degrees, so the "D" might still be considered
somewhat radical by comparison.
I'm using a #149 grind from British Frame & Engine in my TR4 with specs
otherwise similar to your car. I'm not going to use oversize valves. The cam I
chose gives 282 degrees duration and .287 lift (at the cam). The car is not yet
back on the road, so I can't give you a running report. But, I've gotten a
number of recommendations and good feedback about this particular cam. Ken
Gillanders at BF&E is also very knowledgeable about the 4-cyl. TR motor, he's
been
building and racing them since the mid-1950s.
I notice some of the vendors in England are now offering asymetrical cams.
I am not entirely clear on the advantages of these, but am guessing they need
to be ground on new blanks, so are likely more expensive. Revington TR, for
example, offers a Fast Road cam with 270 degrees duration; Sprint with 280
degrees; Rally with 290; and Race with 290.
Watch valve lift with any of these cams, too, so that there is no
possibility of valve spring binding. Also expect to have to run looser gaps on
all
these preformance cams, with a lot more tappet noise as a result. Recommended
for the #149 cam is .016 intake/.018 exhaust.
Some more info on my TR4 project can be found at
http://www.triumphowners.com/640 if you wish.
Cheers!
Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
*************************
Hello list ,currently in position of a Mr.
Kastners F grind tr3 cam in your opinion is this cam to radical for souped-up
tr3 street car ,87mm pistons,oversize valves,lightened steel flywheel? what
does the f stand for? looks by measurement about .010 thous. increasre in
lift and radical increase in duration ,does that profile increase usually mean
a high end (higher RPM power band?Thanks in advance Randy 1960 tr3A
*************************8
|