checking rocker geometry

Reply Subscribe

Thread Tools

Search this Thread

Jan 14, 2015 | 06:32 PM

L98auto

Thread Starter

Instructor

Joined: Jul 2005

Posts: 228

Likes: 13

checking rocker geometry

I have access to a new set of Crane long slot stamped (totally non-roller) 1.6 rockers for my L98. With the increase in ratio does the geometry need checked or not since the stamped rockers have a wide contact patch compared to a roller tip? The cam is a stock flat tappet. Thanks.

Jan 14, 2015 | 08:16 PM

WW7

Le Mans Master

Joined: Aug 2007

Posts: 8,735

Likes: 412

From: WV

Quote:

Originally Posted by L98auto

Yes, if going from 1.5 to 1.6 your geometry may change enough that you could need new pushrods..Actually just going from one brand of rocker to another (same ratio) they should be checked....I check the geometry anytime I change rockers , or lifters .. All you have to do is roll the motor over while watching the rockers to make sure they're staying close to the center of the valve stem while moving the full range up and down, they should also be centered from left to right.You also have to make sure your clearence is ok and the rocker isn't hitting the spring cap, I believe the clearence should be at least .020 at the closest point....I'm not sure about your rockers but what I do is mark the valve stem tip with a magic marker , roll the engine over a couple times , then check to make sure the center of the valve tip is where the shiny wear spot is, to high or to low also means a push rod change is in order.You also have to check to make sure your not getting coil bind on the springs , and make sure the springs can handle the extra lift...There's alot more involved then just bolting them on and driving the car...If the geometry isn't correct, your top end will experience faster then normal wear....WW

Last edited by WW7; Jan 14, 2015 at 08:41 PM.

Jan 16, 2015 | 12:51 PM

vl5150

Racer

Joined: Jun 2013

Posts: 341

Likes: 2

From what I've read here about 40% of the gain in 1.6 full roller rockers comes from the friction losses and 60% from the leverage.

So if a 1.6 rollers make ~14-15 RWHP and this is a stamped rocker then is it really worth the time?

Reply Subscribe

Reply Share

First
Prev
1 / 1
Next
Last

Forum Jump