Originally Posted by opeldean
rally bob:
do you still use a split profile cam when you have already improved the intake flow with bigger valves(42mm) in the stock 1.9 head.
my mechanic was thinking the duration should be around 230 at .050'' with 110 lobe separation..he wants to know about springs. I dont know how to relay the
information in a more intelligent manner to you.but this 230 duration seems so much farther from what you have in your prior posts.
thank you very much.
1-is it possible that you could suggest a cam for me? I would like a solid lifter specific - profile for solid lifters.I plan to learn how to maintain and adjust this set up.
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On the first question, yes, I still use a split profile. The intake manifold, even when ported, is still a restriction.
If you run duration nearer the 230 degree mark, then you might want to up your compression. I realize you are running flat-top '9:1' pistons, but these in fact are closer to 8.4:1 compression. For that kind of duration, a true 9.5:1 is a better starting point. That could be achieved with head milling.
110 degree lobe separation is okay, and the idle will be better than a narrower angle. But if you are striving for more torque, try 108 degrees, with 3 to 4 degrees of advance.
Regarding springs: I don't know of a combination that works with stock Opel retainers and the stock exhaust rotators, unless you use 2.2 retainers and rotators, then there are more options for springs.
Bob