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914World.com _ 914World Garage _ New KB Piston Question

Posted by: tornik550 Dec 3 2011, 08:11 PM

I just got a new KB 96mm piston (I had to replace one damaged piston). The new piston came with two rings that are just a little thicker than the oil rings- they have a dimple on one side. The grove in the piston where the oil rings sit is wider than my older set. The new piston also doesn't have the oil ring locating pin.

What are the rings that came with the piston for?

Posted by: bam914 Dec 3 2011, 08:31 PM

You got the newer style KB pistons. That ring is a support for the oil control ring. It goes on the bottom.

Posted by: tornik550 Dec 3 2011, 08:37 PM

QUOTE(bam914 @ Dec 3 2011, 09:31 PM)

You got the newer style KB pistons. That ring is a support for the oil control ring. It goes on the bottom.

Does the bump on the ring face up or down? If it is up then I would probably have to trim the oil ring. If it faces down then I guess the bump would have to be in the gap for the wrist pin?

Posted by: Jake Raby Dec 3 2011, 09:53 PM

Align the bump down and place in the wrist pin bore relief. This locks the support rail from rotating during operation.
Read the instructions. The pistons changed in late 2009.
I hope you kept the box the rings came in and know which slots they came from, else it's fairly easy to invert the rings and end up in big trouble when you burn a qt of oil every 300 miles for no apparent reason.