Valve Train Issues

[Dane Brahler]

So here's what I'm working with
Stock bottom end
Performer heads
Dss 1.72 rr's (pedestal Mount)
Hydraulic roller lifters
Xe270hr cam (.512 lift)
New springs to match cam

My 6.3" pushrods will torque to spec at 1/4 turn on the rocker arms with a .040" shim. However, the cover across the valve stem seems too long and is on the top third of the valve stem. I used my pushrod tool and determined I needed a 6.5" pushrod to get the cover in the middle of the valve.
Problem here is that i can only get my rocker arm to torque with my shims stacked to .150" high!! What am I missing/doing wrong here?
First picture is my shim stack
2nd pic is cover with 6.3" rod
3rd is 6.5" rod. (Torqued on the .150" shim stack)
Any input helps! This is my first engine build

 

[85ragtop]

Moved to tech.

 

[mikestang63]

my guess is you measured the pushrod length wrong.
Are you using the stock hydraulic lifer and valve spring? You should use a dedicated pushrod length checker lifter and spring.
Is the cam on the base when you are measuring.
if using a stock lifer, is it pumped up
is the head torqued down with the head gasket in place.
Piston at TDC

However personally for this application with those type of pedestal type roller rockers, I think you are fine with the 6.3 pushrods . the swipe does not have to be perfect.

 

[Dane Brahler]

I did use a pushrod checker tool first. That's what lead to me picking up the longer rods. The only issue is the shimming of the pedestal. I just don't know if you're supposed to shim higher when you increase the pushrod length as well. I'm thinking I'm going to use the 6.3 rods now at this point and just return the longer ones. It just didn't make sense to me if I had to shim that high under the pedestal.
And to answer your questions, yes everything else was torqued properly and I didn't have any bleed down through the lifter either. Like I said this is my first build and I'm just trying to learn as much as I can so all input helps!

 

[liljoe07]

If you lengthen the pushrod to get a better pattern, then yes, you have to add shim. Otherwise you would over preload the lifter. The pattern shows that the pushrod is to short. Not being familiar with the performer heads, are they designed to use pedestal rocker or stud mount?

 

[Dane Brahler]

they are pedestal mounted from what i can tell... not sure if they offered a stud mount or really what the difference is. At this point i can either turn some shims at work to use under the rocker guides or i can use the 6.300 rods.

 

[liljoe07]

That shim height isn't bad. But you need to make sure you have the proper thread engagement for the pedestal bolt. If you are going to take the time to measure, I would use the correct length while measuring correctly.