stamped steel rocker arm delection

[Grant Eldridge]

gmonde, I run 240 on the seat, 440 open pressure.
wade, I was surprised how much deflection there is in these parts. When I ran the stock size studs you could see them bend turning over the motor! I have since gone to Clark Holroyd's nice stainless thick studs and rockers, but still have deflection.....Clark now welds a re-inforcement onto his rockers above the pushrod seat, like a small bridge across, that might further help....

[gmonde]

Originally Posted by Grant Eldridge

gmonde, I run 240 on the seat, 440 open pressure.
wade, I was surprised how much deflection there is in these parts. When I ran the stock size studs you could see them bend turning over the motor! I have since gone to Clark Holroyd's nice stainless thick studs and rockers, but still have deflection.....Clark now welds a re-inforcement onto his rockers above the pushrod seat, like a small bridge across, that might further help....

is welding a brace on the rocker legal in stock??? hhmmmm gmonde

[Alan Roehrich]

Approved by Glendora.

[gmonde]

Originally Posted by Alan Roehrich

Approved by Glendora.

good to know,,,thanks for the replys ,,good bunch of racers gmonde

[Alan Roehrich]

If you can get a bigger pushrod in there, and it is legal to open up the holes in the head, you need to go with a 7/16" x 0.125" wall, at the very least you need a premium brand 3/8" x 0.125" wall 4130 heat treated pushrod. You honestly cannot get too stiff a pushrod in a race engine.

[Chris Hill]

Originally Posted by Alan Roehrich

You honestly cannot get too stiff a pushrod in a race engine.

Alan, in a stocker engine with a floppy rocker arm, is the extra stiff pushrod that important?

To quote the cliche, "You are only as strong as your weakest link." If you determine the effective stiffness of the rocker arm and then the stiffness of the pushrod, the pushrod is around 20 times more stiff (or stiffer) than the rocker arm. And since these are essentially two springs in series, the lower stiffness drives the total stiffness of the system.

[gmonde]

i did go from a 5/16 to a 3/8 chromoly push rod .080 wall,i did do some r&d on the rocker arm with several versions of welded rockers,you can get the rocker to stiffen some but you end up adding so much weight to the valve train it would be counter productive it looks like the bottom of the rocker wants to spread out ,,but if you put a rocker in small tool vise, you can see how it flexes real easy with little turning effort ,,its amazing that how much they flex but the breakage is low gmonde