K Series Head and cams questions

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dodgedavidson
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K Series Head and cams questions

I've been helping a mate with his K1600, he doesn’t really know the provenance.

We had the cam cover off and discovered a couple of things that I hope folks might be able to help with.

The cams have been upgraded with Pipers, ground from Piper blanks. I measured them at 9.23mm lift (39.13 – 29.90) and are stamped with part numbers between cylinders 1&2, both have the same part number LGC206250N 13. 

I couldn’t find anything on the Piper website, any ideas what these would be? Supersport? 

I’m sure the head has been ported. I know most tuners mark the heads, I found "CK81" stamped on the rear exhaust side, anyone recognise this?

Cheers,

Roger

StevehS3
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dodgedavidson
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Thanks for the link, didn't find that. Interesting it comes up as a mechanical cam, it's been fitted to a K1600 with hydraulic followers. Not sure what effect that has, hmmm??

StevehS3
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I assume (and it is only an assumption!) that the shape of the cam lobe is changed to to suit the type of lifter (hydraulic or solid).

oilyhands
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According to my data that profile is a supersport mechanical profile, 260 degrees, 9.10mm lift , how well it will run with hydraulic lifters will depend on the lift ramp and valve acceleration.

Oily

dodgedavidson
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Thanks Oily. Is there an easy way to tell if the lifters are mechanical or hydraulic without removing the cams? 

 

oilyhands
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Yes there is, examine the tops of the followers, if there is a dull grey ring around 1.5->2mm in width around the periphery then it is likely they are mechanical, if they have the same silver colour uniformly over the whole top surface then they are likely to be hydraulic. To confirm, use a 6 thou feeler gauge between the cam lobe and the follower top when the nose of the cam is pointing up and away from the follower, if the feeler gauge can be slid between cam and follower then they are mechanical as hydraulic followers run with no clearance.

Oily

revilla
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Sorry to chip in, and I don't want to take the thread off topic but can I ask you a quick question on that please Dave? Is the grey ring something that happens to them running with clearance, or a feature of their manufacture? I'm just wondering how "solidified" converted hydraulic lifters might look after a period of running? Thanks, Andrew

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

dodgedavidson
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Thanks Oily, these look to be mechanical then?

oilyhands
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Definitely mechanical, the dull grey patina on the outside edge is confirmation.

Oily

oilyhands
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Hello Andrew, the solid followers are heat treated when made which gives the upper surface the dull grey patina, in operation the cam lobes wipe the contact surface and in so doing remove the surface layers leaving them silver and shiny. The width of the remaining ring will depend on the cam lift, higher lift cams will leave a thinner ring. Converted hydraulic followers will appear identical to regular followers.