Boxerworks.com

(Source: http://largiader.com/tech/rockers/)

I have a 600cc (/5) engine that I am building from the ground up. Currently, I am looking at the rocker and how to best upgrade them. The heads have the rocker post with 15.5mm outer and 10.5mm inner diamater.

1st Question: the inner post seems to be a sleeve tube, about 26mm long which is pressed in into the head, is that correct? If so has anybody attempted to remove them?

I have original /5 rocker arms & posts and they have pitting. I have /6 rockerarms and post from a 1974 R90S but there is pitting as well. Both sets can't be used.

I do have a set of 1976-up rocker arms (56mm wide) and posts (16mm) which is in good and usable condition.

2nd Question: if I could remove the 15.5mm sleeve tube (see Question 1), it should be no problem to fabricate a sleeve for the bore (about 21m OD) and press-fit the sleeve on the button-type rocker post and then the whole assembly into the head? Or am I missing something here?


Thanks very much in advance for your insight and recommendations. I know there are upgrade sets and all, that but I like the challenge.

Stephen

Anton Largiader has info on this upgrade. You can go to the needle bearing rockers, but you will need to seal the sleeve somehow. http://www.largiader.com/tech/rockers/

Also Keep all rocker parts matched, alot did a change to the later push rods or kept the same push rod and changed the rockers to roller...........

I am interested in doing the same upgrade to a /5. can you please take note post your results here when you have a solution? Thanks! -josh

In my particular case (using 1976-1984 rocker for the upgrade), the final solution presented itself as follows:

• * use original /5 heads and sleeve spacer (O.D. = 20mm, I.D. = 15.5mm, height 11.5mm)

• * modify said sleeve spacer to machine a collar that fits the recessed rocker posts (just turn it down enough to fit in the /7 rocker base, see image below)

• * use the 0.02, 0.03, 0.05mm shims as per BMW catalog to adjust for zero axial play but unrestricted movement of the rockers

Note: pay special attention to the axial play because any play (!) can cause premature wear on the roller cage (axial movement of the rocker pushes the rollers against the ends of the roller cage), causing failure.



(picture courtesy of "wirewrkr")

I have not performed the upgrade yet, so proceed at your own risk.

Addendum: the solution has been provided to me courtesy of Robert "wirewrkr".

Why look at that, Stephen!
Looks just like my kitchen table with the picture I took when I informed you of the solution to your inquiry over on advrider.
That's just not cricket, even for a Canadian! EH?

I apologize, Robert, I truly forgot to include the source and credits for this solution. I have updated my post accordingly.

No biggie Stephen, age will do that.
DAMHIK!