putting together a 1340 shovel with a friend, ordered a set of KB forged pistons when they came in there was no paper work in the box. Talked to a couple of people who said that there is no difference betwen the front and rear pin locaton so it does not matter which goes where. Was wanting to have the top end done over the long weekend. Can anyone who knows confirm this. It is an 81 model shovel.

 

KB has some different clearances than a normal Forged piston so you can fit them tighter, to be sure I wouldn't guess on the installation as many pistons have a pin offset, but not normally on a shovel. Check out the KB website or call them directly as I am sure they would help you out with the details.

 

KB pistons are not forged.they are hyperutetic pistons.they are basicly a cast piston with more silcon in the alloy.You can fit them tighter because they dont have much of a expantion rate.These pistons also hold a lot of heat from the top ring up.Your top ring end gap has to be much more than with other pistons.If this is not done the ring ends will butt togeather causing all kinds of damage.If memory serves me I belive your end gap should be .016 to .018.

 

We don't use KB pistons here.
Not the good rugged piston we want to see.

 

I have KB pistons in my '82 shovel. Unless the design has been changed the only orientation is the valve pocket relief in the piston dome. Orient the larger relief toward the intake valve.

Piston ring gap is determined by multiplying .006" times the bore diameter.

Stretch the spirol lock out to about 3/4" and start one edge in the grove and with a small screwdriver press it in as you go around.

Be sure to use a good after market ignition system and retrofit a VOES.