Scott's response to Craig:
Craig Bentley wrote:
[...]
> head, oversized pistons, etc.) and I came across a "crowler" brand regrind. I
> was wondering if any one knows what the cam specs for a stock cam are. The
> crowler lists as .405" lift with 266 duration.
Craig,
Here's the stock cam specs for a TR6, note that the lift is advertised
at the cam, so multiply by the rocker ratio (1.5 for U.S. market car) for
total valve lift.
IO IC EO EC DUR DUR LIFT RPM RANGE COMMENTS
10 50 50 10 240 240 .220 Early TR6, also GT6
18 58 58 18 256 256 .240 2000-5000 Late TR6, '72-'73 and on
22 63 63 22 265 265 .280 ? This is the cam in my car, 9.5 CR
31 71 71 31 282 282 .285 3500-5500 S2 Cam, used in PI models in Europe
29 69 69 29 278 278 .281 2500-6000 Isky Z19, what I would use on
the street
It looks like the cam you have is very close to the cam I'm using. Of
course I haven't started my car yet, so I can't give you any
particulars on it! Since you mention that the duration of your cam is
266, it sounds very very close to the cam I have. I'll let you know
how it goes once I've started it up. The S2 cam which is a common
street cam for TR6's is nice, but I really don't like the high RPM
range that is advertised, which is why I like the Isky Z19 for an all
out street cam.
Note that the performance mod book for TR6's states that for a street
car, it's better to go for lift rather than duration if you're faced
with that choice. The cam I have in my car was inexpensive, so I
understand your choice as well.
You CR increase will make a significant difference, and port matching
the head will improve things as well. Without a HP exhaust, and other
mods, I personally don't like the higher duration cams, as I keep my
RPM range below 5000 rpms. The longer duration cams really make HP as
the higher RPMs, not where I like to drive my car on the street.
In short, I think you'll be happy with the cam you have, and it will
take advantage of the other mods you mentioned.
Cheers,
-Scott Paisley
'75 TR6
Scott/Craig,
I'm running a 266 duration +.4 lift cam in my '72 TR6. I've put about 2000
miles on it since the rebuild and it runs great. There's good power from
2000 rpm up to 4000 rpm. Lots of torque at about 3000 rpm which is good
for passing on the highway. The idle is smooth. The motor has a .060"
overbore and the head was skimmed 0.060". I'm running the stock duel pipe
exhaust and modified Strombergs. The car passes the California smog check
without any problems. I was told that once the duration is greater than
280, passing the smog check here may be difficult. Once you get your
engines running I think you'll be happy with your cam selection.
Pat Starr
El Dorado, Calif.
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