Ok, I got a pushrod length checker and I'm trying to determine the correct length for my setup. In the picture the left valve had the stock pushrod (7.2"). Based off of THIS reference, I know I want a narrow line in the center of the valve tip--so since the mark is high, it's clear that stock length is too long. The right valve had the Pushrod Checker set at 7.1". As you can see it is centered but it is not narrow. Also, the mark doesn't go all the way across--it's clearly biased left. Is this OK??? Is the Comp guideplate pushing the rod out of alignment?

Valve tip Mark

 

Loosen your studs and do it again.See if the pushrod's will self center the guide plates and look OK.You need to coat the complete tip with marker.

 

I did mark the entire tip, just looks different in the photo. As suggested, I backed the studs out and re-installed them, but I still get the same result. If I lengthen the checker, the line goes up, if I shorten it, the line goes down. But in either case the line does not go all the way across and it never gets any narrower. Anyone else have an opinion??

 

Did you try leaving the studs just barely tight(finger tight) and see if they would align. The marks look like the rocker is canted or the valve stem is not flat in relation to the stud. The guides may be worn a tad causing the valve to be not 90* to the stud.

 

Ditch those comp guide plates and get the GM plates; that will center the rocker over the valve. Try to set the PR checking tool to 7.150 and check the pattern it should narrow it up a bit with out moving the pattern off the center line.

 

I never did like that style of checker.Use your RR you are going to run and adjust the pattern to be in the center and as narrow as possible.You may not get a real narrow line but getting it in the center is more important than width.If they are not centered your guides are going to take a beating,if you have much lift.

 

I tried it with the studs finger tight and it did help--the line almost went all the way accross. It definately appears that the rocker is not centered on the valve tip. Unless something else is wrong, I might have to switch out the Comp guideplates that come with my AI setup with GM--just not sure if GM guideplates will work with Phil's upgraded AI one piece pushrods. I'll talk with him next week.... Thanks for the replies.

 

Personally prefer the push rod length that will give the least 'swipe' (friction) across the valve stem along with as centered as possible. This cuz, it MAY not be possible to achieve both precise centered and narrowest contact pattern at the same time. This combination may cause the contact patch to not be exactly/directly on center of valve, but believe it will give overall less (or no more) guide wear than a wider, although centered contact pattern. A wider pattern, caused by increased sideways scrubbing of rocker.

 

The narrowist swipe will make more power but its not always close to center, in fact sometimes you need to comprimise. In my case the narrowist pattern was way to the exhaust side of the valve tip and almost ran off the edge. I didnt think plucking the tip would be a good idea so I had to comprimise and find the shortist path across the center. Its not ideal but should work well IMO.

 

Ditto--- The swipe don't mean **** ALL if it ain't centered and your guides are worn out in 5000 miles,from not pushing close to center.

 

COMP guideplates WON'T work on an LT1! The valve spacing is .050" wider than a typical SBC. This won't affect your pushrod length swipe, but typical SBC plates on an LT1 will not align your rocker tip (side to side) correctly. Bolt a couple on and you'll see what I'm saying. When I tried it, a few of my rockers were hanging on half the valve tip. If I tried lateral adjustments, it knocked the corsponding rocker off.
GMPP is the ONLY company that makes bolt on guide plates for LT1's.

Frank