Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models K Piston Rings

K Piston Rings

Post Fri Nov 14, 2008 2:56 pm

Posts: 591
Location: Crewe, Great Britain

Hi Ritchie,

Don't have any WL pistons to compare with my stash of KH pistons, BUT, rather than buy straight away a good new pair of WL to fit in your KH/KR project, just invest in one dead WL piston and check for yourself with a 1/2 crankcase + crank + piston. You'll know the depth of your heads from measuring them, substract .5 to 1mm (20 to 40 thou) for the squish band, see how far more the WL piston pops up, (it's bound to be more than KH std as 8mm = 1/2 stroke diff WL to KH as I'd rather think the diff between WL and KH piston height is more like 4mm) , the result will be the height of the plates you'll need under your cyls.


Post Mon Nov 17, 2008 11:16 pm

Posts: 121
Hi Richie,
I measure the WL at –2mm against the KH piston... can you get them custom made; it's not all that expensive?

Best, Nick.

Post Tue Nov 18, 2008 9:02 pm

Posts: 391
Several things are going on with the pistons. WL pistons are shorter from the piston pin centerline to the crown. However, The placement of the rings is also different. If you attempt to use WL pistons with WR or KR cylinders that are relieved the the top ring is too close to the bottom of the relief and the rings will fail. One of the reasons that the stroker flywheel guys do not recommend using their stroker pistons in WR/KR cylinders. I have a couple pair of K/KR pistons that have different crown heights. When I asked on this forum before if anyone knew why there was a difference I got no response. K and KR piston rings are further down from the crown than WL.


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