Athena base spacing, piston port clearance question.

Sooooo should the piston clear the exhaust port or the exhaust and transfers as well? Seems like it should be the transfers too but that would require quite a lot of spacers and decking the cylinder to get the squish back to .8mm. When I did my wizard I just cleared the exhaust and it worked great but I want maximum hrsprs outta dis bish.

Re: Athena base spacing, piston port clearance question.

Dirty30 Dillon /

Exhaust is the real killer, and you don't want to space the cylinder out to expose the transfer floors if it means the piston will be well below the exh port.

Re: Athena base spacing, piston port clearance question.

Yeah the transfer floors are lower than the exhaust. That's what had me a bit confused. Why would Athena not have the floors be even with each other?


Re: Athena base spacing, piston port clearance question.

Probably Fred /

Now I don’t know how thick the crown is on that kit piston,

But on a stock puch magnum cylinder and cheep kits sometimes a similar situation arises so I Dremel down/file down a bit (then polish) top sides of the piston top down to match the transfers like this but much smoother then my finger writing shows, feathering it to nothing before the crown


If you have to just split the difference, you don’t wanna cut too much into the piston top to match the transfers, just like 1,5- less then 2mm Feathered to nothing at dome

Pistons are usually thick at the sides so you can make a halfway decent cut in the beginning then feather,

Sometimes I match the head squish to the cuts in piston but even without doing that I noticed good gains but again this was on free stock pistons or cheep 27$ Kit pistons,

Though I never really messed up, I never Messed with a expensive Athena piston but I would now because I’ve done it several times and it’s just Moped’s

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