Need an assist with Crane adj ductile iron rockers

[bth0320]

Hi folks,

For those that use these rockers, I am hoping you can assist. This may be a dumb question but the instructions (and the pictures) are not real clear regarding the use of spacers and shims. I am installing these on Edelbrock performer rpm aluminum heads and some of the pushrods are hitting the side of their respective slot in the bottom of the head. Should I be using those thicker "C" looking spacers with this type of head or the shims that look like thin washers....or does it matter which I use as long as I get the pushrod in the correct position? Should I be using one or the other regardless if the pushrods are hitting? Originally I put the rockers on without the use of either the spacer or the shims. The instructions seem to contradict themselves when using aluminum heads and I have no idea what they mean by protrusions in the rocker stands....

As always, thanks for your help!
Brian

 

[lewtot184]

in my experience, usually the push rod rubbing the bottom of the intake port wall is due to a very high lift cam, and the head needs to be relieved. check the scrub pattern at the rocker/valve tip area to make sure the rocker tip is centered over the valve tip. the semicircle shims that fit under the shafts at the stands are for correcting rocker geometry. the thin circular shims can be used to locate the rocker tip over the valve stem. ductile iron rockers, any make, usually have geometry problems with high lift cams.

 

[bth0320]

The pushrods arent hitting the intake walls but more towards the shafts/hold downs.....sounds like I just need to shim a little. Here is a quick pic....

 

[lewtot184]

a 1.6 rocker would move the adjuster inward possibly causing interference but those look like 1.5"s,....?

 

[bth0320]

They are 1.5's.....I have a call into Crane Cams to see what they think.