Author Topic: Are pistons tapered?  (Read 1034 times)

Offline priderocks

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Are pistons tapered?
« on: September 17, 2009 - 04:49:32 PM »
I have a set of Arias forged pistons, std. bore, for a 383. When I put my dial calipers across them, it appears the skirt (if that's the right term) of the piston is a larger diameter than the top of the piston. Is this normal?




Offline matt63

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Re: Are pistons tapered?
« Reply #1 on: September 17, 2009 - 05:29:33 PM »
I think so.  I'm a little rusty on this but the piston should be measured up and down below the rings (skirt).  If measured above the rings it will be much smaller.
Matt in Edmonton

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Offline 72cudamaan

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Re: Are pistons tapered?
« Reply #2 on: September 17, 2009 - 08:00:47 PM »
Yes that is correct. Actually a piston skirt is oblong and tapered. The piston manufacturer always marks on the box or puts a tag in the box detailing where exactly to measure the piston for an accurate actual dimension. This info is to be used by the machinist so he knows what size to finish hone the bore to.
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Offline Chryco Psycho

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Re: Are pistons tapered?
« Reply #3 on: September 18, 2009 - 12:13:08 AM »
 :iagree:
 the piston is oval for expansion & the top is slightly smaller diameter than the skirt

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