another cam question

[LilBill]

what's the difference in cam design that neccessitates dividing them into 3 types ? 48-69, 70-77, 78-84. will any of the cone cams work in a genny ?

[Old Crow]

not sure about the 48-69, but the difference between the other 2 is the gear.  The A grind I'm running was previously in my bud's '76 shovel.  I had to press his gear off and put mine on.

[Hillside Motorcycle]

Good question.
Never measured and compared.

[Hybredhog]

   Lets work our way backwards kind of. The camshaft itself for 70-84 is the same, only the gears are cut differently for mesh specs., & can be pressed on & off or exchanged. 69 back to 47 use the same shaft & gears, but can't be used on later shovels, due to the outside cover race is smaller & has no ign. drive slot. Pans have a 1.5 rocker ratio, and shovels have a 1.7(dusty memory), so travel clearance has to be really watched on pan installations. Knuckles use the same shaft diameter as pan/shovels, but rocker ratio is 1:1, so lobs are totally different...Jeff

[randallwhitman]

Jeff....I'm pretty sure that the shovel rocker ratio is less than a Pan's.  Around 1.43:1?  Randy

[76shuvlinoff]

eff....I'm pretty sure that the shovel rocker ratio is less than a Pan's.  Around 1.43:1

That's how I understand it too.
I installed Jims 1.5:1 roller tip rockers in mine.

[ricochet]

It's pretty much summed up already.  In choosing an S & S oil pump and associated pinion and drive gears I confirmed that 78 and up use a different pitch on the gears.  With consideration for the rocker geometry you can go both ways year wise by matching the pitch of the meshing gears to each other.  I'm using a shovel S85 cam for my panhead build which as advertized is a .590 lift yielding about .619 in a panhead due to the different rocker ratio.

ricochet

[ricochet]

Oops!  I did forget to mention that as Jeff pointed out the difference in ignition drive slot on the cam end for 70 and up versus generator type is significant.  In my case I'm using a Sputhe type generator case cam cover that has a cone morphed into it so the 70 to 77 shovel cam I'm using will work.

ricochet