PDA

View Full Version : Lift exceeding flow. please advise



LowBuckX
12-12-2006, 11:59 PM
I purchaced a 406 some time ago and have tore it down and Im changing cams and some other stuff. The original owner claimed it had1.6 rockers but the 1.6 rockers morphed into 1.65s (original owner insits Im wrong but ive measured a number of times)

I have no geometry issues or binding. Piston to valve clearance is at .120 with out gaskets. Measured with a solid lifter (roller) Cam button clearance is .004-.005
My springs will bind @ 650 lift so Im clear there.

As is Ive got .580 on intake .593 exhaust

Here comes the question

By all the info Ive found my heads (TFS 23*) will putter out at .560 intake and .570 exhaust.

So that makes about .020 lift past where the heads stop flowing.

Is this going to be Good, Bad or indifferant.


__________________________________________________ ______________-

I remember an Engine masters Small block contestant claiming .858 of lift but I cant remember his reasoning though.

Found it http://www.popularhotrodding.com/enginemasters/0302_leftcoast/ Tom Nelsons

andrewb70
12-13-2006, 06:12 AM
I am a dummy when it comes to things like this, but I will relay some information that I was told one time regarding this subject. You want the valve to go past the point of max lift a little bit. This will keep the valve open at the max flow lift a little longer. Sort of like shifting a few hundred RPM past your peak power. Made sense to me. I am sure someone has a moce scientific explanation.

Andrew

Lowend
12-13-2006, 12:22 PM
I would say its indifferent

Going past peak flow lift point does serve to increase dwell at peak flow point slightly. If you go too far it can hurt things, but with this small of a number I doubt its having a measurable effect