Predator 224 GC 1.2 Roller Rocker Seizing on Exhaust Side

[jason.talley161]

I’m running a Predator 224 with a 275 cam, 26 lb springs, and GC 1.2 roller rockers.

My problem is the exhaust rocker keeps seizing when I tighten the rocker stand bolts. The strange part is:

1. If I swap the stands between intake and exhaust, the problem still happens on the exhaust side.
2. The rocker seizes even with the pushrod removed, so pushrod length isn’t the issue.
3. If I loosen the stand bolts slightly, the rocker moves freely again.

This makes me think either:

- The exhaust rocker slot is slightly too narrow
- The threaded holes in the head are pulling the stands inward

Has anyone run into this with GC rockers on a Predator 224?

Would you recommend:

- shimming the stands
- grinding the rocker slot slightly
- grinding the inside faces of the stands

Any advice would be appreciated.

 

[Whitetrashrocker]

I would tighten just to the point of binding and loosen it off just a tad.
Then rock it back and forth to make witness marks where it interferes.
Then decide if it needs a shim or a grinder taken to it.
Being either rocker binds on the same side, I would lean towards the mounting stand.

 

[panchothedog]

What does GC stand for? Is that Gage Corporation?

 

[Eztrail]

Casting of the head might be off from side to side

 

[Wicked_Daddy]

I'm going with EZtrail and WTR on the slight difference from the 2 stands. I believe you are referring to EC 1.2 ratio rockers. Although Gage makes a set that are similar and GC could be Gage Company? Anyway, the rockers share a common shaft/axle. If the Exhaust rocker stand is just slightly lower, this could put enough of a bend in the shaft to lock the rocker at the curvature in the shaft. Shims would fix that.

A way to test for this would be to torque the intake rocker down while leaving the exhaust side untightened - perhaps only insert the exhaust rocker bolt loosely to hold the exhaust rocker in place while torquing the intake. Does the exhaust rock freely? Then remove the loose bolt and use a feeler gauge to see if there is a gap between the shaft and the stand. It doesn't have to be much to cause binding. If this confirms your issue, the feeler gauge will also reveal how much shim you'll need. You could also take a little off the intake stand, but that would require careful, incremental adjustments until everything works as designed.