A
Anonymous
Guest
Well, i broke ANOTHER cap bolt holding my roller rockers on (3rd time)! DAMN. Something is just not right.
Here is the setup:
OZ2502V with original springs(shimmed .060)/valves
Yella Terra full roller rockers from Mike (his site says 1.65 ratio)
DUR @.05 @1.5 @1.6 @1.65 lobes
Cam: 264/274: 214/224 : .450/.450 : .480/.480 : .495/.495 : 110*
Based on YellaTerra's site, this is what I have:
144 - 250 Inline 6: Shaft type (1.65) ST2014
*requires Cleveland lifters and 9.130" pushrods (i would say it's safe to assume that mike sold me the right lifters and pushrods BUT he was getting seriously dicked around by his PR vendors when trying to get mine...maybe I should check them to make sure!)
To me, it would seem that the range of motion for the rocker is being exceeded for some reason at some point causing enough forward (toward the spring) pressure to snap the cap bolt. Each time it would seem that it's hapened right at the top of the bolt near the first threads (I guess the threads are the weakest point not the solid shoulder area).
When last I adjusted the rockers, I purposely left them a little loose to avoid this. I figured that it has to be related to too much push rod lift right? So by leaving the adjuster a hair looser, maybe it would leave enough room for that extra lift that happens for some reason. Guess not.
I thinking that maybe these pushrods are just too long for my setup since the block was decked to .010 and the head milled a bit and I'm using an NOS steel headgasket. Could that be it? Combine all of this deck lowering changes = too long on the pushrods? If that be the case, how then do I get an accurate measurement for the right lenght PR's?
When it happened this am (after I got my replacement cap screw), I started to bolt the rocker head back on. I could not get it to tighten down to the pedestal as it was contacting the tip of the pushrod even with the adjuster backed out all the way. It was like the lifter was pumped way up. I turned the motor over a bit to get it back down so I could install it, but that just didn't seem right. What would cause this to only happen sometimes?
from YT site:
"All rocker arms have a limit to their rotation, at some point the arm will hit on the stud, posilok, pedestal or head of the retaining bolt. It is vital to ensure the operating range of the rockers on each engine configuration is within these limits to avoid severe damage."
Sound like what I'm experiencing.
The YT rockers came with washers that apparently are used to raise them up a bit. We did not seem to need them when first intalling the rockers, but maybe I need to go back and add them now to take up some of this lenght?
The way the YT's fit is this (pics at bottom: http://cquesttechnologies.com/fspp/rockers.asp?cat=24):
- there are 2 thick steel "pedestals" that bolts to the existing rocker shaft mounts. The rockers bolt to them.
- the rocker arms bolt to the pedestal through small (maybe 1/2" tall) steel cylinders that the cap screws slide threw. The rockers actually rest on top of these cylinders
The part in the instructions that was not clear at all was where fo the washers go if you want to use them? Under the pedestal? Under the cylinders? On top of the cylinders?
I know I'm supposed to adjust them with the motor warmed up, but when I remove and replace them, should I wait for the motor to completely cool down so that the lifters can settle?
Thanks much guys.
Here is the setup:
OZ2502V with original springs(shimmed .060)/valves
Yella Terra full roller rockers from Mike (his site says 1.65 ratio)
DUR @.05 @1.5 @1.6 @1.65 lobes
Cam: 264/274: 214/224 : .450/.450 : .480/.480 : .495/.495 : 110*
Based on YellaTerra's site, this is what I have:
144 - 250 Inline 6: Shaft type (1.65) ST2014
*requires Cleveland lifters and 9.130" pushrods (i would say it's safe to assume that mike sold me the right lifters and pushrods BUT he was getting seriously dicked around by his PR vendors when trying to get mine...maybe I should check them to make sure!)
To me, it would seem that the range of motion for the rocker is being exceeded for some reason at some point causing enough forward (toward the spring) pressure to snap the cap bolt. Each time it would seem that it's hapened right at the top of the bolt near the first threads (I guess the threads are the weakest point not the solid shoulder area).
When last I adjusted the rockers, I purposely left them a little loose to avoid this. I figured that it has to be related to too much push rod lift right? So by leaving the adjuster a hair looser, maybe it would leave enough room for that extra lift that happens for some reason. Guess not.
I thinking that maybe these pushrods are just too long for my setup since the block was decked to .010 and the head milled a bit and I'm using an NOS steel headgasket. Could that be it? Combine all of this deck lowering changes = too long on the pushrods? If that be the case, how then do I get an accurate measurement for the right lenght PR's?
When it happened this am (after I got my replacement cap screw), I started to bolt the rocker head back on. I could not get it to tighten down to the pedestal as it was contacting the tip of the pushrod even with the adjuster backed out all the way. It was like the lifter was pumped way up. I turned the motor over a bit to get it back down so I could install it, but that just didn't seem right. What would cause this to only happen sometimes?
from YT site:
"All rocker arms have a limit to their rotation, at some point the arm will hit on the stud, posilok, pedestal or head of the retaining bolt. It is vital to ensure the operating range of the rockers on each engine configuration is within these limits to avoid severe damage."
Sound like what I'm experiencing.
The YT rockers came with washers that apparently are used to raise them up a bit. We did not seem to need them when first intalling the rockers, but maybe I need to go back and add them now to take up some of this lenght?
The way the YT's fit is this (pics at bottom: http://cquesttechnologies.com/fspp/rockers.asp?cat=24):
- there are 2 thick steel "pedestals" that bolts to the existing rocker shaft mounts. The rockers bolt to them.
- the rocker arms bolt to the pedestal through small (maybe 1/2" tall) steel cylinders that the cap screws slide threw. The rockers actually rest on top of these cylinders
The part in the instructions that was not clear at all was where fo the washers go if you want to use them? Under the pedestal? Under the cylinders? On top of the cylinders?
I know I'm supposed to adjust them with the motor warmed up, but when I remove and replace them, should I wait for the motor to completely cool down so that the lifters can settle?
Thanks much guys.