S cam timing on 2.7

[ginot912]

did a partial tear down, had 3 pulled head studs, 2 on intake #1 and one on intake # 2.
Any way, all that went well using time-serts.
now the timing, I have a inch dial indicator, I was reading 4.37 revolutions on # 1.
edit- here's a picture of one just like it in next post

Spec for the cams is 5 to 5.4 mm
I checked #4 and that is reading 4.42 edit- which was set many moons ago.
car was pulling strong before the pulled studs. should I try to get to the Ideal 5.2?

I did repeat the process many times and always came to similar #'s.
except the few time the crank binded, which I promply stopped and started over.

I've read many timing threads, so I kind of get it.
and I will be re checking in the am..

yes I'm a newby with the engine internals

thanks

Gino

[ginot912]

[Flat6pac]

The higher you go on the spec window the more low end power is available and you have to realize as the chain stretches the numbers will drop back, as you ve seen on the other cam setting.
Bruce

[ginot912]

thanks Bruce
re-checked this am
with fully torqued left side (did not have fully torqued before) the # came up to 4.40
so now left and right are real close.

going to install
DE this Fri.

Gino

[camgrinder]

Originally Posted by ginot912

thanks Bruce
re-checked this am
with fully torqued left side (did not have fully torqued before) the # came up to 4.40
so now left and right are real close.

going to install
DE this Fri.

Gino

4.40 mm puts the factory S profile in 4 degrees retarded. 102 degree intake centerline. I would move them back to 5.0mm (98 degree) if it was mine.

I understand the idea of increasing top end performance, but the 911 S has a very short exhaust duration lobe. By retarding the cam you delay the exhaust valve opening point. This reduces valve lift at BDC on the exhaust stroke. Can lead to a pumping loss and counteract your goal for more top end power.

[ginot912]

thanks for the info, John