GN-1 pushrod clearance issues

[S2V6RACER]

Got a call today and more bad news. The pushrods on the two middle cylinders (Intake) are rubbing. He said he needs about .400(or a little more) offset in either a rocker or lifter. He tried moving the shims, but that moves the rocker off the center of the valve. I haven't seen it I am just conveying a message and would appreciate any help out there.


I thought I read this somewhere a while back but my search turned up nothing.

Info: GN-1 R heads on a Stage II on-center block with T&D rockers 1.55 ratio.

Ted

 

[Fuelie600]

Don't mean to step on your post Ted, but I was reading your sig. and am curious as to what head gaskets you were using on your stock block set up? I am using the 109 block w/ GN1's and run 25 to 29 lbs. of boost w/stock gaskets (GM) and o-ring wire in the heads. Never lost the fire ring, but graphite in the motor really sucks. How did your gaskets hold up? Thanks Brian

 

[HighPSI]

You need to run offset lifters.

 

[Chuck Leeper]

P rods and the head

Ted, hyd roller or mechanical?? I had the same problem. Am using a hyd roller, so no offset lifters available...
ended up machining the heads to clear.. They won't clear by much, but did clear...

 

[EightSecV6]

where are they rubbing?

 

[S2V6RACER]

Lifters

Solid Roller. Only the 2 intakes on the center 2 cylinders. I am going to go over and look at this with my own eyes. Man, the most frustrating thing about this whole project, is how I pointed all these "fitment" issues associated with Stage motors out a long time ago. I often wonder why I have to even bother when I am paying him to do the job, I've lost count on how many trips I have made there.

 

[EightSecV6]

What dia pushrods are you using?

 

[TurboTR]

You only need 2 offset??

TurboTR

 

[S2V6RACER]

5/16" 6.100 long sent directley from Tom at Champion. PTE has offset rollers, and Rich was going to call Tom at Champion and ask if he has 2 offset rockers. To put salt on the wound he is charging me $140.00 to "clearance" these pushrods, as he said that others needed some filing to clear at full lift.

 

[S2V6RACER]

Originally posted by Fuelie600
Don't mean to step on your post Ted, but I was reading your sig. and am curious as to what head gaskets you were using on your stock block set up? I am using the 109 block w/ GN1's and run 25 to 29 lbs. of boost w/stock gaskets (GM) and o-ring wire in the heads. Never lost the fire ring, but graphite in the motor really sucks. How did your gaskets hold up? Thanks Brian

FP 9004 B if my memory is correct. I don't know how they look, the motor is still together in the car. I have not had 1 gasket failure aside from a valve cover gasket that needs changing

 

[ZNX]

pushrods

I have GN1 14 bolt heads with T&D 1.55 roller rockers on stock block this required all pushrod holes to be clearenced milled about .400 even valve covers needed notching.

 

[Fuelie600]

Thanks Ted. I've never failed a gasket using the stockers, but I have found graphite flakes in the oil during changes. Yesterday I pulled the motor and heads and found deterioration of the graphite aound the fire ring on cylinders 3 & 4 due to the head yeilding under high boost. The head yeilding doesn't bother me, but graphite throughout the motor does. Looking for a non graphite gasket that will seal the fluids and be aluminum freindly. Is this too much to ask? Thanks Brian

 

[odell4o8]

push rod clearance,

i have champion R heads on off center block i had to open the push rod holes , i use 1.65 ratio shaft rockers. i sold gary harmon a set of offset mechanical rollers, i dont know if he is going to use them or not, you may give him a call. i have another set, that im going to keep, oc,

 

[S2V6RACER]

The end result was offset lifters. I really needed only 1 but Comp cams said I needed a whole set because there was a weight difference between the two styles of lifters. Be aware of that when you build one of these motors, and mock up first to find out if you will need them or not.

PTE took back the old lifters and sold me another set. No hassle at all. My experience with Patrick Rubio there has always been good.