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914World.com _ 914World Garage _ Who scored an A in Geometry?

Posted by: cgnj Jun 22 2004, 03:28 PM

Hi,

The 2270 motor has been sitting waiting for me to get off the dime with the pushrods. I'm gunshy because I hosed my Al set. Tips didn't match.

I have the same adjustable pushrod and CrMo pushrods that Dave is using in this threadhttp://www.914world.com/bbs2/index.php?act=ST&f=2&t=13478&s=

How do you measure this rod after the geometry is set? Tips don't match the CrMo set either.

The details
.160 cylinder shim
.060 rocker shim
adjusters decked

Carlos

Attached image(s)

Posted by: SLITS Jun 22 2004, 04:31 PM

Without being able to draw on a chalk board, I'll try:

The chrome molly is probably the "button" type, in that, it is a hollow tube with the ends pressed into the tube.

The rockers should be in the stock position or horixontally parallel to the rocker box surface. There is some HP to be gained by running an odd geometry at the sacrifice of increased guide wear.

We would seat the lifter with the push rod with the engine at TDC. With the push rod not in the rocker socket and laying next to the rocker seat, we would scratch a mark on the push rod to be cut to make it the approximate length that would be required to keep the rocker in contact with the valve and the button seated in the cup.

At that point we would chuck the push rod in a lathe and start cutting the tube away with a cutting tip (I'm not a machinist). As the button has a shaft that seats into the tube that is, say 0.250" long, we would cut away 0.125" of the tube, down to the shaft of the button and then smack the tip on the table to reseat it.

It was a matter of cutting behind the button till we got the length we wanted and then cutting the rest to the same length.

OR

If the Al pushrod was the correct length, the compare it to the chrome molly and cut the tube away behind the button till you achieve the overall length you want.

My scientific method

PS I didn't look at the photos