HELP! Bottom end noise

[Matchymarty]

the rocker gear .......the exhaust rocker assembly............. the exhaust rocker spindle.......... what is the specified float in the exhaust rocker spindle?

Marty, I'm assuming you're referring to the valve cam gears, shaft, and cover, not the 'rocker' ditto. which is at the top of th'engine.

Without sight of the bits I can only suggest that you compare the substitute gear, it's teeth, cam profile and the cover with the one you removed to see if there is any physical difference.
I'm not sure how you could be precise in shimming the zorst cam by ""putting a spacer in between the exhaust rocker spindle, to space it to match that of the intake assembly"" as the intake gear spindle is not visible when the cover is fitted. Perhaps you over-shimmed the zorst gear creating excessive end float in the (now noisy) intake gear spindle. The spindle end float required is just sufficient to give running clearance as there is no significant heat to cause any expansion.

Personally I'd just throw another shrimp on the barbie, pour a beer and enjoy the silence.

Spriddler, No, I'm referring to the rocker assembly. The exhaust rocker assembly has 1/8" - 1/4" float side to side in the Rocker box housing. The Rocker spindle or axle sits in a sleave, then in 2 brass bushes in the rocker box housing. Due to this float, (of which the intake rocker assembly has next to no float) we decided to turn up a bush to space out the exhaust rocker spindle from the housing to match that of the intake side. We did not alter the position of the rocker arm/tappit. Strangely, it seems that taking this float out, created noise in the exhaust follower in the bottom end, and or, it made the exhaust cam gear move in and out together with the timing chain, causing all sorts of noises.

We have swapped for another rocker box assembly which has the 'float' in it, and noises are gone! So.... moral of the story... "if it ain't broke..... "

Still curious to know WHY?

[56G80S]

I remember replacing the bushes and axles and the standard adjustment method I thought was to move the bushes a bit. Mine are slightly slack so there's a bit of end float more than I planned but only thou's and all's run fine; my experience on this kind of thing is that too tight is more problematic than too loose although it's better to be on the button.

Difficult to visualise what you've done but are you sure that the relationship with the arm and the top of the valve is right?

Johnny B

[SPRIDDLER]

Hmm, without being there I can't offer a reason for it, and even if I was there I'm not sure I could tell you why the noise has gone, and I'm fully occupied wrestling to solve Fermat's Last Theorum, creating perpetual motion, and stopping the local cats pooing on MY lawn. It's a life

BTW - I know you're not using the head for which you made a bush but the originals were/are phosphor bronze. I don't think the softer brass bush would last very long, although long enough to prove a point, evidently.

It seems unlikely but it just may be that the noise is/was not due to the cams/rockers at all but something obscure, like an adjuster not being secure/tight in the end of the pushrod and hammering.............