Rocker Arm Shaft Question
 

How much wear is considered acceptable for the rocker arm shafts? I was disassembling my heads last night and was surprised at the amount of scoring that I noticed on my shafts. Is this considered "normal" wear? Thanks in advance.

I am thinking anymore then a shadow would be too much

You can measure the outer diameter with a caliper. I recall mine were 18.02 mm, surprisingly all of them were. There are tolerances mentioned in Wayne's book.

I would be concerned for reason for the "wear"

I consider more than .0003" unacceptable.

Wow, 3 10thousandths! My micrometer isn't that good, but no wonder they were all 18.02. Thanks camgrinder.

Well, I don't have a spec book for an '87. You should absolutely have one, or the factory workshop manual, to guide you through all mechanical work.

My old book for the '65-68 cars says the specs are:

Rocker arm shaft: 17.992-18.000 mm

So the difference is 0.008mm, or 0.00031496063" (which is exactly what Camgrinder said, 'cept in "English." :) )

The rocker shaft bore in the cam housing is listed as 18.000-18.018.

Some scoring seems to be common on the shafts. That doesn't mean they are worn out. You can check with a micrometer. I install them with the scored surface on the "outside" so the smooth surface wears for the second life of the engine. Worn out rocker arm shafts and bushings will be noisy. Not dangerous but annoying.

-Andy

Thanks for the input. I'll "mic" them tomorrow and see where I am at.

Anything wrong with Eagledriver's process? Aren't these under pressure from the "bottom" only?
Thanks