Pushrod help

[dragracerray]

Originally Posted by motoheada1

Hey there

I'm currently finishing up a Gen 1 SBC for my Chevy II. When I went to measure for pushrods, I decided to try a "new to me" method called the half travel method. That method gave me a longer than expected dimension, and tip wear pattern out on the exhaust side of the stem. So I tried the other two methods I've used in the past, the plastic rocker gage, and centering the wear pattern, all with different results. Both the wear pattern and the and the half travel method seem logical, but end up with very different results. Looking for some feedback from the one's that are in the know!!!

Chuck

Chuck,
I don't know if I am "in the know" but here is what I do. I always to rocker geometry measurements with the intake off. First thing I do is make my own adjustable pushrod. If you have fancy ends on your race pushrods you would have to cut up a fancy pushrod to make an adjustable pushrod. Cover the end of the valve with Sharpe. Install the adjustable pushrod with the adjustable end near the lifter where you have more room. Lash the valve. Rotate the engine from zero cam lift to max cam lift back down to zero cam lift. If you can not see the witness mark clearly in the Sharpe than rotate engine again. When you have a good image remove the rocker and inspect the witness mark. If the the witness mark is not centered on the valve readjust the pushrod and repeat. When you are satisfied borrow a dial vernier that is big enough to accurately measure the pushrod you want. As others have said make sure you have no interferences rocker to retainer, rocker to stud etc. Ray

[Adger Smith]

Don't get the pushrod so long that it is pushing on the rocker cup at an odd angle and increasing the load and stress on parts. I would sacrifice a pattern or few thousands in lift to keep the pushrod and cup in the right position.
as that cup goes up and in toward the stud the load on the cam, pushrod and lifter increases. IMHO too much attention to the valve side can create other issues when compromise is necessary.
I always used my Cam Pro Plus to plot valve movement.
I always considered the real issue getting the geometry where the cam profile is transferred/duplicated at the valve.
There you go Curtis Reed.....
Well said, Rich