 Engine Assembly Question, Which way do the pistons face? |
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| ThinAir |
 Mar 27 2005, 06:10 PM
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Best friends  Group: Members Posts: 2,569 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region 
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I'm about to install the Mahle Euro (flat top) pistons and cylinders. I know that it is critical to have the pistons facing the correct direction relative to the flywheel. I'm used to seeing an arrow on top of the piston that is supposed to be pointed toward the flywheel. These Mahle pistons have no such marking.
This picture shows the top of the piston. Is that funny little symbol supposed to represent a crankshaft & flywheel? Is it critical which side faces the flywheel end or just that all the pistons are the same? I'm hoping someone answers quick - I'd love to get the heads on tonight! Attached image(s) 
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| Dave_Darling |
Mar 27 2005, 07:19 PM
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#2
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914 Idiot Group: Members Posts: 15,335 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California
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The funny symbol, in this case, is a crankshaft and a flywheel. Squint a little bit--see it? The flywheel is on the very right-most side of the glyph, which means that the right side of the piston (when viewed from the "top") should be closer to the flywheel.
The reason the symbol is there is because the pistons have very slightly offset wrist-pin holes. This keeps the forces going from piston through connecting rod to crankshaft (and back the other way) lined up a little bit better, which reduces the "piston slap" and the piston rocking in the cylinder bore. It's not critical, but it's a good thing to do correctly if you can. --DD |
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Posts in this topic
ThinAir914 Engine Assembly Question Mar 27 2005, 06:10 PM
Mark Henry Look on the backside...one of the pin bosses will ... Mar 27 2005, 06:27 PM ThinAir914 Mark -
Here's the bottom of the piston. Mar 27 2005, 06:33 PM ThinAir914 I'm guessing from your description that the le... Mar 27 2005, 06:35 PM ThinAir914 It took me awhile, but I found this page at Mahle... Mar 27 2005, 06:44 PM Mark Henry Yep left side
All mahle pistons have some sort of... Mar 27 2005, 06:56 PM ThinAir914 Thanks, Mark! The first P&C is just about rea... Mar 27 2005, 07:17 PM Joe Ricard silly rabbit tricks are for kids. the picture of ... Mar 27 2005, 07:21 PM ThinAir914 Thanks guys...
Now, about deck height. I assembl... Mar 27 2005, 07:33 PM Mark Henry You should figure out your proper CR then get cust... Mar 27 2005, 07:52 PM Joe Sharp Mark: Your trying to make an engine builder out of... Mar 27 2005, 09:12 PM ThinAir914 That's OK Joe. I want to understand why, not ... Mar 28 2005, 12:20 AM MarkV You have to cc the heads and allow for the dish in... Mar 28 2005, 12:29 AM ThinAir914 I was using the value of 60cc that Mark Heery prov... Mar 28 2005, 12:54 AM MarkV If your combustion chamber is in fact 60cc's a... Mar 28 2005, 01:08 AM Mark Henry Things like flycutting the head can change figures... Mar 28 2005, 08:04 AM
type47 i'm doing the same thing (assembling the engin... Mar 28 2005, 09:01 AM |
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