Phillip Babcock wrote:
>Been reading about cam recommendations.. and here is what I did in
>Feb/98 to get 150hp.
>Bored .030, 12.5 compression pistons, 125E Rods, Steel mains (might not
>have needed but might want more power later), kept stock crank (thats
>keeping from going higher), steel tappets, cams with .434 lift, 1.625 &
>1.375 valves, head cut for valves and springs, special valve gear. Head
>ported and polished. Kept 40mm Webers for now.
Having the spring pockets cut deeper, for a high lift cam, is one very
important item that I omitted from my previous camshaft comments to
Tor. This is important. You basically have no other choice but to do
this, to avoid spring bind with high lift cams, but IT MUST BE DONE
VERY CAREFULLY so as not to cut through into a water passage and trash
the head. This is an operation that should best be left to someone
with considerable experience working on twink heads!
Phillip, that seems quite a serious 1590cc engine, with "Hart small
valve" valve sizes, very high compression, and a cam with lotsa lift.
Do you remember the duration?
>On my chassis dyno, I have tuned the car for max using 104 Gas at 128hp
>@ 6200 RPM at the rear wheels. That's 150.5hp at the flywheel given the
>standard 15% loss through a manual Tranny.
Wow, that's a bag-o-torque. 127 ft-lbs at 6200RPM, which seems pretty
extraordinary, at the power peak, for a 1590cc engine. Do you have a
header that really emphasizes that particular RPM range?
What is your peak torque, and at what RPM?
>If I buy a steel crank I can then change only the cams and get much
>higher hp
Yeah, I think you're right. You're already making good horsepower
using what seem relatively low revs... cams with just a little more
duration, along with bigger carbies, would probably buy you a bunch
more hp by moving everything up in the RPM range.
What parts are you using in the way of springs, valves, keepers,
guides, etc. etc.?
Regards,
Erik Berg
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