NHT early HP rocker shafts VS HP shaft with flats!

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https://www.accessnorton.com/Norton...-650-ss-from-england.9628/page-18#post-435730

This issue from the above topic being discussed had started a thought process of what has happened in this transition from LP puke pressure lubrication and the ramifications of the initial single small hole oiler used in the HP system.

An initial analysis showed the very tiny linear contact transitioning from the hole to the rocker surface area.
oil hole is approx .093" gives .292" of linear contact for oil to exit the shaft onto the rocker shaft surface. This makes me wonder how effective is it wetting the surface?
The same hole feeding the flats provide 1.922 linear inches of access to oil the shaft/rocker.
The shaft is physically unloaded for 3/4 of the time, then for 1/4 of the time it is to be moved under a very high physical load. Now with a more wetted shaft/rocker interface, the rocker rotates down from the wetted surface toward the high physical contact area on the bottom of the shaft. Seems a better operational condition to me.

I have noted in several forums and discussions to find heads of this HP small hole/no flats era to have rocker that have possibly/probably seized to the shaft from lack of lubrication and then started to rotate the shafts destroying the heads shaft bore. Some damaged quite dramatically... A higher oil flow also cools the shaft and rockers.

I have not proved a thing... but I can't stop and wonder why a noteable amount of heads of that era have suffered such damage. The change to the SS high lift cam with new stiff springs may be contributing to the high loads and corresponding heat being generated locally in the rocker system.
I certainly would never use the small hole rocker shafts...
 
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Make sense, May also be why they reduced the width of the rocker and increased the load bearing surfaces for the rocker shafts?
 
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Yes,I'd agree In hopes that the better HP oiler more than makes up for sacrificing a little steel off the rocker for more shaft supporting aluminum.
 
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FWIW
The early NHT rocker shaft head bore is 3/8"(.375"+/-) long. The late NHT rocker shaft bore it 5/8"(.625"+/-) long.

ARE YOU OFF YOUR ROCKER ???

1. I looked more closely at the original production scrolled rocker shafts (with the flats).
2. I started to measure the rockers to find the location of the ball oiler holes.
3. Comparing the relative positions of the shaft scrolling and the flats, to the rocker hole it made me wonder what is the " actual/primary purpose of the flats"?
4. I was trying to keep in mind...why are today's scrolled shafts no longer including the oiler flats?

A. Agressive lube the ball end ie flat facing toward the ball end
OR
B. Agressive lube the sector of rocker just in advance of heavily stressed swept arc angle ie flat facing away from ball end
In this condition the ball end lube hole is pretty much centered in between 2 scrolls!

C. other ???
 
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