3.0 SC rocker arm and bush measurements

[derm.1785]

Hi all, I’ve looked but can’t seem to find details on rocker and shaft dimensions, wear limits etc. I’m inspecting my parts and need to know if I can rotate or need new. Thanks.

[proporsche]

the rocker shaft are either good or no good from just looking at them....
let`s see pictures of yours.........

ivan

[derm.1785]

Some have a very light groove line in them which is typical wear. I’ve measured them and some are out by 0.01, they measure 17.98 at the ends and 17.97 in the middle ( my gauge doesn’t go any smaller ) they aren’t scored either. I can’t find any wear limits for these anywhere ?

[proporsche]

they looks just fine, do not sweat it....

Ivan

[Walt Fricke]

You could try the finger nail test: if you can feel a semi-circular wear mark, either rotate or replace? I've rotated a couple of times, as the wear is along the loaded surface, before purchasing new ones.

It appears that it is less expensive to purchase new shafts rather than to try something more exotic, like maybe flame spraying and regrinding to spec.

The biggest worry seems to be that wear will affect the angularity of the rocker, thus causing uneven wear on its cam pad side. I don't know how serious that might be, and rockers can be reground as long as they aren't pitted or worn above some limit set by the shop which does the grinding, typically along with a new bushing.

[Zuffenwerker]

There is a recommended clearance between bushing and shaft. I’ll try to find it for you Monday when I go into work. You could also call someone who rebushes them and get some info on what they recommend.

Daniel

[derm.1785]

Daniel, if you could find the spec it would be great. Walt, thanks for your comments, I know I can rotate but it would be good to know if mine are in limit.

[targa72e]

I happened to have the spec book next to me while reading this. below is the specs for rocker to shaft clearance. Last time I had my rockers rebuilt I also had the shafts polished. This was done by Dougherty cams.




john

[Classic 911]

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[proporsche]

as i said these looks ok and they don't really go bad unless there is a lot miles on them and poor maintenance..more often the rocker brass bushing will wear out...
Ivan

[David Inc.]

What's the thought on buildup of rust and corrosion at the ends of the shafts where the tapered nuts and washers go?

[proporsche]

Originally Posted by David Inc.

What's the thought on buildup of rust and corrosion at the ends of the shafts where the tapered nuts and washers go?

personally i have never had any problems(solid steel material) with those you are mention..The only problem i had is when mechanics put the shafts in the wrong way or strip the allen head bolt..that is no fun

Ivan

[David Inc.]

Originally Posted by proporsche

personally i have never had any problems(solid steel material) with those you are mention..The only problem i had is when mechanics put the shafts in the wrong way or strip the allen head bolt..that is no fun

Ivan

I just have some grunginess and grit between the face of the washer/nuts and the shafts. It makes me concerned about how they would seat and stretch if I don't have them cleaned up (or replaced) first.

[proporsche]

always clean and inspect , i use wurth HHS 2000 to lube the threads

Ivan