<VV> Standard size piston

[RoboMan91324 at aol.com]

Were the 40 over piston/jug set across from each other?   Generally 
speaking, you would be well advised to match all six.  Otherwise, unwelcome 
resonances could be set up.  However, like  the Porsche Boxter, the Corvair has a 
boxer engine.  This means that  the pistons move in and out in pairs.  In 
effect, the front pair move in  and out at the same time and the same with the 
middle and rear pairs.   This is important ... The oversized pair must be 
matched in the front middle or  rear positions.  Again, mismatched pistons are 
not the best thing for your  engine and I would invest in 40 over 
pistons/jugs for the other four; especially  considering that the engine is already 
apart.  Either that or replace  the over 40 sets with standard.  However, if 
you are desperate to save  the money, you might not notice a vibration with 
the standard/40 over setup if  the system is set up with matched pistons 
across from each other.  Keep in  mind that moving piston/rod assemblies from 
place to place on the crankshaft may  cause issues with the bearing/shaft/rod 
interface.
 
By the way, while it is apart, you may want to check the  balance of the 
moving parts if you have the ability or the money to  invest.  The previous 
mechanic may have taken other shortcuts.  As  implied above, you can save a 
few bucks and/or some time because it is more  important to match each of 
three pairs to each other than it is to match all  six.
 
Doc
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
In a message dated 8/29/2016 9:00:06 A.M. Pacific Daylight Time,  
virtualvairs-request at corvair.org writes:

Message:  5
Date: Sun, 28 Aug 2016 23:59:54 -0400
From: air_cooled63  <air_cooled63 at yahoo.com>
To: virtualvairs at corvair.org
Subject:  <VV> Standard size piston
Message-ID:  <vbkeql5ncvd9swsqxtdxlru0.1472443194748 at email.android.com>
Content-Type:  text/plain; charset=utf-8



A first for me. While  checking out a mystery engine, I found 2 cylinders 
that was bored 0.40 the  rest standard. I guess it would run ok. Will match 
them all to standard.Jerry  Brown?


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