top end oiling

[vern]

Seems to me that the big nuts on a knuck rocker box could be turned to adjust the oil flow to the rockers, any one out there in knuckle head land know about this?

[ricochet]

As far as I know the big nuts only serve to hold the rocker shafts into the aluminum rocker housings and seal that end.  Even if by turning that nut you were able to turn the rocker shaft it would make no difference because all oiling channels on the shafts are cut around the whole shaft.  There are holes in those channels allowing oil through the shaft centers then to the rockers themselves.  One could get creative with changing any of this like hole sizes, adding holes and what not but then you run the risk of upsetting the delicate balance of this system.


ricochet

[vern]

I have oil puddling in the intake ports that must be coming from the rockers via the guides any suggestions, it's a S&S motor

[ricochet]

I know that some folks have restricted oil to the heads by narrowing the passage of oil either at the fitting in each head or at the base of the feed line.  I chose to do so by making a brass plug in the fittings for each head and drilling it out to like .080.  Don't hold me to the size.   In many cases this is needed when using a more modern oil pump or pump parts with increased capacity such as that probably used by S & S.  I'd bet they have something to say about this.  Also if your rocker bushings are excessively loose on the shafts more oil is free to make it's way into the tins and overwelm their capacity too.  Do not loose tract of the fact that oil removal is dependent upon a vacuum seal in the push rod tubes.  Many times it's this lack of vacuum that's causing the backup.

ricochet

[vern]

MY first Harley was a Knuckle and I had some sort of manual and I'm sure that there was some of info on reducing the oil to the heads but that was before cameras or the internet, a long time ago. But your info about the newer pump and how to reduce the oil is very helpful. thanks. Vern

[Speeding Big Twin]

Vern, I’ve never owned a Knucklehead and I have no experience with S&S engines but I have some info regarding adjustment. However, I do NOT know if it’s good info so please CHECK FURTHER before using it.

I have a book called Inside Harley-Davidson by Jerry Hatfield and when mentioning the introduction of the 1936 Knuckle, Hatfield states on page 142: ‘The amount of oil supplied to the inlet rocker shaft was adjustable by varying the position of the rocker shaft in the rocker cover. The oil arrived at the shaft through a groove cut around the circumference. This groove was cut eccentrically. The rocker shaft could be rotated clockwise or counterclockwise to expose the incoming oil to deeper or shallower portions of the inlet groove. This regulated the amount of oil entering the shaft. After adjustment, the inlet rocker arm shaft was tightened against the rocker housing. Oil moved horizontally along a groove in the bottom of the rocker arm shaft to form a boundary layer between the stationary inlet rocker arm shaft and the moving inlet rocker arm.’

The tech tip below is from the March 1980 issue of Easyriders magazine and it mentions adjustment. But once again, I do NOT know if the info is good so please CHECK FURTHER before using it.     Eric

[vern]

Hi Speedy.

Thanks, I knew i'd seen this artical somewhere! Harley Tech Talk has been and contiues to be a wealth of information. My knuckle manual does not say anything about adjusting top end oiling but there it is in black and white. Thanks again.

Vern

[ricochet]

Wow!  You learn something every day.  I wonder if this were only 1936 as designed first engines.  If I understand it the oil groove in the rocker shafts would have been ground to be eccentric to the center of the shaft.  Is that right?  Or is it just a matter of positioning the hole from the groove to the shaft center in line with the feed?  If it's the latter then one has to wonder if it would net any appreciable diffference since once the groove and holes are flodded they are no longer the gate so to speak.  Seems the cost of special grinding operation would be considerably more that using a lathe.

Very interesting.

ricochet

[vern]

The Harley Knuckle manual sez that there is no way to control oil flow to the rockers. but I'm going to have a look at the bike I'm working on and see if it is possible. restricting the flow by using a plug also sounds interesting. Those little return lines just don't seem adequate.