Date: Sat, 19 Feb 2011 18:22:26 -0500
Reply-To: Joe Luther <jluther@ALFONS-HAAR.US>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Joe Luther <jluther@ALFONS-HAAR.US>
Subject: air cooled piston weight/cylinder question
Content-Type: text/plain; charset="US-ASCII"
I've started going through the disassembled 60k mile spare engine I got with
my Vanagon project (2.0 air cooled). I also got my Bentley manual today.
Today I worked on the pistons and cylinders, cleaning/stoning and looking
for the markings on the piston crown and condition of the cylinder bores.
Good news is that 3 pistons have identical markings, "93 97", "-" for
weight, the arrow for orientation, and what appears to be a manufacturers
logo at the bottom. The third piston has a "+" for weight, no 93 97, and a
different manufacturer. It was very clean on top, the others had buildup on
top. The cylinder bores for the 3 identical pistons are gorgeous, I can
still see the crosshatching. The cylinder bore that mates with this odd
piston has almost a chromed appearance and the crosshatch is much less
visible. Also, the cylinder body has a 5 digit number beginning in 8,
(maybe 85587) that appears to be acid etched in the outside of the cylinder
body. I thought all pistons had to be marked the same weight class, + or -
?
I'm planning on looking at the 84k motor tomorrow to see if one of the
pistons on that engine has a 93 97 marking with the - weight class and good
piston crosshatching, and if so, swap cylinder and piston over.
My plan was to replace rings (I broke one oil ring getting it off so I'll
need replace them to anyway) and I was going to rehone the cylinders but I
am thinking not because the only difference I can see on the 3 'better'
cylinders is the coloration of the cylinder wall outside of piston
travel.....the crosshatch appears the same. The odd cylinder could get
honed but that would still leave me with the piston that is a mismatch.
That doesn't seem right.
Any comments/suggestions on the above?
TIA
Joe
PS - the driveway is no longer a luge and I took down the dead trees
threatening the parking area so the Vanagon can finally come home tomorrow.
Technical Manager
Alfons Haar Inc.
150 Advanced Dr.
Springboro, Ohio 45066
937.560.2031 main
937.560.2032 fax
937.560.2037 direct
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