Larry, The prechambers have holes in them to direct the jet of fuel sprayed into the combustion chamber. The Star shaped
( Milled) pistons are supposed to match up with the spray pattern of the precombustion chambers. The round tip ones have three holes in them. The slant top precombustion chambers have four holes in them in different locations from the round tip combustion chambers which have three. If you try to use the slant top with the star shaped combustion chambers they will not direct the flow fuel in the right direction. The MB manual says you cannot use the slant top precombustion chambers with the star shaped pistons.


I hope this helps

MBJOE