750SF2 - rocker axial play when spindle end sits low

[mikeb]

Hi
For reassembly, I thought I’d test fit the rocker spindles prior to deciding about shims to minimize axial play to the 0.2mm figure I’ve read about. Before dissembling, the left exhaust had 0.63mm play and the left inlet close to 0. But when I test assembled these and drove them both fully home (inboard) the exhaust spindle is now recessed below where the cam end cap would hold it in, and as shown (in the pic) is close to 0 (while moving freely).

If the cam end cap stops the spindles moving outboard, then do I have to assemble with the end cap, drift it out then measure for shim thickness? Or maybe it should not be recessed, even tho it is? Or cut a shim disk to sit outboard of the spindle to hold it in, under the cam end cap? Or maybe I’m overthinking this?

Any guidance gratefully received.

thanks!

 

[Tippie]

I drive them in with the head warmed up but able to handle with bare hands, as it nears home I stop it with just a bit of end float and check that the rocker lines up ok on the cam lobe ( with variation I have seen some that hang over one side, which I try to avoid). If it drives home and there is excessive float I remove the pin and shim either side of the arm to have it centred on the cam lobe. Rarely does the pin sit proud of the head surface from my experience.
Check that the holes in the rocker arms are not blocked in any way, they feed oil to the cam lobes.

 

[piranha-bro2]

The cam end cover gasket will compress into any minor recess after you've driven the spindles home. I generally just check for excessive side play - never thought to look at the position of the rocker face relative to the cam lobe.

You can also try different spindles in each rocker to see if you get a good matching combo with minimal side play for each pairing. My technique is to grind the stop face of the spindle very carefully to allow it to recess further before it bottoms out (thus reducing side play), but again, this doesn't factor in the alignment mentioned above by Tippie. I prefer this than fitting fiddly shims.

I mount the spindle in a chuck and use an angle grinder with a cutting blade mounted solidly on a pedestal drill or lathe saddle ... you don't want to take too much off!