Rocker arm geo on 1776

[eccentricvelo]

Hi all,

I acquired a fresh 1776 long block from a buddy who is getting out of VWs. Since it's been sitting for a long while, I've torn it down, checked clearances, and made sure everything generally is correct. So far so good. As I'm getting things buttoned up, I'm trying to figure out the rocker geometry. Forgive me if I use incorrect terminology or if I'm doing something obviously incorrect. I'm comfortable with regular maintenance, but this is my first complete engine build.

The cam is a Webcam 163 with 044 ported heads and 1.25 rocker arms. According to my calculations, the lift should be .479, but in practice it's closer to .494 - is that too far out?

I am having a really hard time trying to figure out the rocker geometry. The photos I've attached are at half lift at .247 and the numbers are the amount of shims under each stand in 0.030 increments. I think the pushrods may be the culprit? I have an adjustable one on order, but I want to see if I've missed anything else in the meantime?

Using 1x 0.030 means I have 0 adjustment - I can only just barely set 0 lash on #2 exhaust.
2, 3, and 4x 0.030 photos are attached
5x 0.030 - the adjusters are all the way out and flush with the locknut. This felt wrong.

Pushrod is 277mm long from tip to tip.

Thanks in advance!

[Bruce.m]

What are you aiming to achieve by adding the spacers? Just checking you aiming for the right goal.

Camera angle & lighting make it difficult to judge but “2” looks the best.

[slayer61]

Hi all,

I acquired a fresh 1776 ....

The cam is a Webcam 163 with 044 ported heads and 1.25 rocker arms. According to my calculations, the lift should be .479, but in practice it's closer to .494 - is that too far out?

......

Thanks in advance!

OP, I can't help with your geometry. I have to leave that for others who have actually done it.

I CAN help with ratio rockers though. You're seeing the variations involved with mass production.
A quick search of the web finds a "cam lift" of the 163 cam at .3837". If you multiply that by the 1.1 of OEM rockers, you get .422" and if you multiply that .3837" by 1.25 you get your "expected" goal of .479". You are also seeing that your rockers are closer to 1.29:1 (1.3:1)

Very seldom do they come in "exactly" at 1.25