Rocker Arm Geometry

I was going to suggest lash caps but I see you've already got them. I guess the installed height of your valves isn't as high as you'd like on those heads.

I have heard of guys having the rocker stand blocks machined on the bottoms .040 or .060" in certain instances so the geometry looks better.  Are the rockers close to perpendicular to the valves at half lift?  Are you doing this with a light checking spring so you can see the contact pattern through the cycle?

Al, did you look at the pictures? It appears, correct me if I'm wrong, that Sharpie was applied to the lash cap. You can see the contact pattern.

Machining the rocker blocks sounds like a good option. I had forgot about doing that. I'll be doing rocker geometry soon myself when I get the customer motor built to that point.

I just got the rocker shaft blocks machined today. The picture below is 1/2 rotation -0.030" lower on the rocker shaft assembly. For this set up, am I aiming to get the adjuster end parallel with the valve cover flat? Because I have been using the sharpie on the lash cap for reference.

Yeah, you want the pushrod and the lifter to be exactly perpendicular at half lift. Are the pushrods exactly parallel to the cylinders? They angle a bit downward away from the cylinders, don't they?

I LIKE the Sharpie trick, and I'll be using it!

I was right, there is an angle.

You look perfectly fine with that contact pattern.

Here's a pic, don't mind the 3/8" extension substituting for a pushrod. It's about 5 degrees off perpendicular to the valve cover face.

I worked on rocker arm geometry today on the 2276 I'm building. I'm waiting on a Total Seal #2 compression ring set and machined cylinder spacers, otherwise the long block would be built. I have a set of .090" spacers, but need .180" so they got stacked temporarily on one side to do the geometry.

This picture illustrates what JB is talking about perfectly. The exhaust valve on the left was no shims installed, and the intake valve on the right is with two shims of .060" so .120" just to illustrate the point. More shims moves the contact area away from the rocker stand, which makes sense since the valves are tilted slightly toward the rocker stand.

I'll be taking the rocker blocks to a shop to take .030" off the bottom.

The Sharpie trick is AWESOME! Thanks!

Tomorrow I'll throw the lash caps on first. That should move the contact towards valve center, the same as lowering the blocks.

@DannyP, what style rocker are you putting on this motor?

Berg 1.45:1. These have the pushrod side adjuster, similar to my Pauter 1.5:1 rollers on my motor, but without the roller. They're very nicely made and forged.

These were on the motor originally. Pretty much the only re-usable part along with the case.

@DannyP, you are going to run lash caps on the valves?  I was a little confused that you were checking valve geometry without having them installed.

Yes, just doing a mock-up. Realized I need the height on the valve tip after I was done for the night. I was just playing with the Sharpie technique...

I'll play with it more today and should end up with a proper pushrod length, contact pattern, and degree the cam(Web 86b) as well.

I got after the geometry today. Webcam 86b and Berg 1.45:1 forged lifters. Lift is 0.551" at the valve. CB CNC 044 Super-Pro 45x37.5 heads and port-matched manifolds. CR 9.8:1, 82 stroke x 94 bore. Chambers are flycut to 58cc, 2276cc should be a screamer on Weber 44 IDF in a Spyder.

Just need to cut the pushrods, my adjustable pushrod is set to the correct length.

The contact pattern on the lash cap is perfect even though the picture doesn't show well. I used dry erase marker this time.

Full lift:

Zero lift:

Two threads above the locknut and two threads underneath. Rocker is tangent to pushrod and valve at half-travel. I forgot to take the half-lift pic.

Also the cam card verified with degree wheel and dial indicator.

That looks perfect!  Nicely done, Danny.