Cam /valve lift?????AU - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

useless · 10-20-2004, 23:43

Hi ..Iwas just wondering if say a cam has 6.7mm lift on a 16 AU ..what would be the lift at the valve?

Perana XR8 · 10-20-2004, 23:46

i think the rocker ratio was 1.8 on the AU I6's so 12.06mm Valve lift...

I may be wrong with the ratio though...

useless · 10-21-2004, 00:33

The reason I am asking is because I have a new AU XR6hp cam and a dev4 in my shed which I am sorting out.While my ford manual quotes cam lift they do not quote valve lift.My dev 4 is quoted lift at tdc on the valve rocker.So if I find full lift and zero my dial indicator...rotate the cam then I can find the base circle which would read 12.06 mm.From here I can proceed to to tdc where the cam should read .97mm lift. or 11.09 on the dial indicator. If not the vernier will do its job.

You see Ihave bought some engineering books on cams .They are awesome.They make easy work of degreeing a cam in.

I was surprised to find that a vernier gear is really essential on a regrind cam which because of machining has its angle changed.
Alot of people say it is because of stretched timing chain.Well I dont buy that theory any more.
A billet cam which is machined correctly should fit into standard timing gears.

jonbays · 10-21-2004, 03:16

Perana XR8 is right the rocker ratio on the AU and late EL is 1.8:1.

So if your cam has 7.42mm lift the valve lift will be 13.36mm.

useless · 10-21-2004, 03:57

Hahah!!Got it.So my cam with .97mm lift at tdc should have 0.5303mm lift at the cam.!!So essentially I can degree the cam before the rocker gear even goes on right?

Soxx · 10-21-2004, 04:03

Even billet cams need clocking up.
I've built many engines over the last 18 years, and I don't recall many cams that didn't need clocking, both billet and regrind.

Rick.

useless · 10-21-2004, 04:15

Quote:

Originally Posted by Soxx

Even billet cams need clocking up.
I've built many engines over the last 18 years, and I don't recall many cams that didn't need clocking, both billet and regrind.

Rick.

So even a stock xr6 hp can benefit from dialling in?

Soxx · 10-21-2004, 04:29

It certainly wouldn't hurt.
I'll go out on a limb here, but I suspect that is one of the main contributing factors which make some cars from factory feel like they have more power than another of the exact same model.

Rick.

useless · 10-21-2004, 23:47

what is the lift at tdc for a standard cam?

grogfather · 10-27-2008, 05:37

i have a ford au 2000 straight gas 6 cyl auto, hurricane extractors, 2 and a half inch sports exhaust, i am to believe it has a ea manifold & carbi, would like to know if anyone can tell me what cam to use to hear some lump on idle with little or no modifications i have been told i had to have head shave and valve spring and computer change is there away around doing all this to get the sound i am after