over lightened rocker arm

Hi All,

I hope some of you may be able to give some advice. In my effort to lighten the load on my valve train, I have just nicked the oil feed galley way on my left exhaust rocker arm. The galley way is exposed for about 3mm (maybe 1/8 inch in the old money). In defence of my work, I found that the galley way was not centrally drilled in the arm - I had only cleared the casting flashing off the arm when it exposed itself.

I think I have 4 options:
1. silver solder
2. bronze weld
3. mig/tig
4. new or used replacement (probably hard to find)

Anyone's thoughts?

Do you need to lighten the rocker arms in a commando engine if your self-imposed rev limit is 7,000 RPM (due to the bottom end) and you are not using dramatic cams ?

Tossem Out .
Dime a Dozen , grab twelve sets and X - Ray them to get a Set where the Oilway is Central . :lol:

You mayve gone to far , this time , young Lad .

Heres looking at you ; eye-candy-rocker-arms-t14490.html

Ty I did exactly the same thing so think Norton just laid a waxed string in each mold to cast passages close to the surface. I couldn't think of any sure way to reseal and not just plug or pop off again so bit the $80's bullet and go another to finish a bit less off that area. Here's Peel's tested long hard and way over red line no problemo and will be reused in her next edition.
Main mass to remove is valve end and most noticed advantage of getting most off the very end it stops the push rod fumble jumble so they slip right past each other every time. ahhhh... Don't be fooled by my top view sharpness, I didn't take much off the sides where the oil passages lie. I was careful enough to bench grind with the ball ends in place.

Yes Indeed ,

Hand tool & youre prefered sustanance , unhurried Cleaning Up / dressing of surface irregularities ( on a set without oodles of dings & nicks )

The top & Bottom extremities of the arms ARE the Beam Strength . Thinning there isnt going to strenghten them . Reduceing the extremities ,
Particularly OUTSIDE the aadjusters etc , reduces inirtia in the arm . The main idea is to produce a smooth ( as reasonable , DONT go to the lowest irregularity , perhaps )
progressive surface with no sharp changes of conture . So you dont go into the fillet radiouses twixt arm & shaft other than to knock of unnessesary high spots .

A quick dressing with your favourite bastard files to highlight high spots , then a cautious progression being carefull not to slip & cause grooves or hollows .
Likely tecnically fileing along & out the arm , particularly finishing , would be prefered .

Some PO has had a half hearted attempt at the rockers in my engine with what looks like an angle or bench grinder. I am hoping to make a better job of it when free time allows an just smooth them without going as far as Hobot as in his picture as they look scary !!!
Some of the adjusters are tight which I believe is a common problem. Is it a good idea to run a tap through those to clean up the thread or will this removal of metal weaken the thread so that it tightens up again? Or should these rockers with tight threads be scrapped? If tapping is a good idea then what is the thread form of the adjuster ??
Thanks

hobot did not go quite as extreme as Dunstall example, so actually have plenty of reserves left and got tested beyond what any one else has. I did take care to remove/polish out any stress riser scratches from bench grinder, one of my most favorite machinist tools, next to hand drill with buffer wheels. Again lightness is Rightness but its more righteous to spend and remove mass on the valve side of geometry than cam side. There's decades of 8500-9000 rpm survivors with factory lifters and push rods, but they didn't use the Norton valves/springs. Also I cheated and had rockers and valve kit cyrogenic tempered, after the grinding to save my expensive tooling.

They are forgings right? Is it a characteristic of forgings to have a hard surface layer? Heat treated? I did a set by hand with files and you could tell after you get to a certain layer it gets very soft by comparison to the surface. But if nobody has ever broken one then the strength must still be up to it. Dunstall's are kinda scary to look at though.

Castings, me thinks.

Looking at mine I to would say they were cast an not forged

I would say they are drop forged steel. Good strength from the steel - just that the flashing hasn't been fully ground off.
By the way, I managed to find a NOS for a very reasonable price to replace my error of judgement and the oilway is much more central. The factory must have hand drilled the rockers using a very sloppy jig in the first place.

Cheers

Sloppy Norton production, who'd of thot, so ya didn't over lighten yours, just stumbled on luck of the draw. Do show us what ya end up risking in the end.