R16 Pushrod Length (Ford Lifters) - Check?

[Daryl Smith]

Stock Pushrod shows 7.83" length
Isky D-013 Pushrod shows 7.687" length
Racing Prep Manual says cut .250" from stock pushrod (with cut head) or 7.58"

So.....I have a slightly shaved head, and am using Ford Y-block lifters, which are taller than stock, and roller rockers....
I was expecting a pushrod length close to the Isky D-013, measuring it with an adjustable pushrod (Comp 7709-1) I am getting 7.493" (7.5").
Geometry looks good on both the ball and roller ends of the lifters....

Anyone else come up with this length, or close?

Thanks,
Daryl

[Daryl Smith]

Looking closer at my rockers while measuring for the pushrod, I've noticed 4 rockers are off center of the valve. Pictured is the worst of the 4, but, not by a lot.
Anyone have a source for some spacers? Stock rockers don't have the 'shims' like the aluminum rollers....

Have also confirmed 7.5" for the pushrods with 5/16" ball and cup for this setup. Aftermarket pushrod will be both stiffer and lighter (better valve control).
Would recommend a measurement on your pushrod and check your valvetrain geometry when modifying this engine.

[zippy67roadster]

I run Isky shortened ones that go with the Ford lifters in my #13 FP 1600 racecar.

[fj20spl311]

I wounder if the rocker is designed to run off center just a little. I remember something about that causing the valve to spin that keeps it clean.

[23yrRebuild]

I wounder if the rocker is designed to run off center just a little. I remember something about that causing the valve to spin that keeps it clean.

I believe it's the lifters that are caused to rotate, by the angle of the wipe areas of the cam lobes....I could be wrong...

[david premo]

That’s correct the lifter has to rotate or the cam will go flat and the lifters will become dished on the rubbing surface as it continues to wipe in the same spot.
Dave

[Daryl Smith]

Need 4 shims @ .025" for the 20mm rocker shaft...
Anyone have a source?

Thanks,

[Andrew Griffith]

Do you have the supplier for the roller rocker ?

[fj20spl311]

For Sure the lifters have to rotate, but I heard the valves are also designed to rotate.
That is why the keepers are designed to fit loose on the valve and tight in the valve retainer.
I Don't know?

[Gregs672000]

There are videos taken inside an engine with high speed cameras that show the valves rotating. Pretty cool stuff.

[Daryl Smith]

In this video it looks like the springs, retainers, and locks are all spinning, likely the valves also.....?
Just scroll down a bit to the video.
https://www.enginelabs.com/engine-tech/ ... evolution/

[Daryl Smith]

I run Isky shortened ones that go with the Ford lifters in my #13 FP 1600 racecar.

Sorry Zippy,
I was thinking you were just using the Isky D-013.....are you saying you shorten this pushrod? Do you happen to know what you shorten it too?