Date: Tue, 22 Feb 2011 12:16:49 -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: Re: air cooled piston weight/cylinder question
In-Reply-To: <BAY152-ds13544A5B50ECF7302C1CBCA0D80@phx.gbl>
Content-Type: text/plain; charset="us-ascii"
Thanks for the information, Dennis. I'll definitely check into the Total
Seal rings.
The 93 97 pistons are Mahle, I found the ID cast into the underside of the
piston. The other piston is definitely different, putting it under the scope
here at work I found a 93,98 on the top as well as a KS logo, KS is also
cast into the inside of the piston body so it should be a Kolbenschmidt. I
would be happier finding another Mahle 93 97 - piston/cylinder set on the
other engine to replace it (assuming the cylinder condition), it just looks
different. Maybe it was the only one the PO cleaned.
The case is definitely going to be reused as are the cylinders and pistons,
I can't afford to replace them. With 60k and 84k on the engines, I hate to
think I would have to, is that really a mileage point where this engine
would be worn out internally to the point where they would need replacing?
That was a major selling point on the project, the inclusion/availablity of
two engines with known low miles. The body and interior are very good, the
engines were the tipping point.....
Joe
-----Original Message-----
From: Dennis Haynes [mailto:d23haynes57@hotmail.com]
Sent: Tuesday, February 22, 2011 11:17 AM
To: 'Joe Luther'; vanagon@GERRY.VANAGON.COM
Subject: RE: air cooled piston weight/cylinder question
On the air cooled engines the piston-cylinder sets really are consumables
and being matched sets is critical. There have been different suppliers and
even Mahle has offered different piston materials such as cast or forged.
While forged is lighter-stronger they have to run with more clearance making
piston slap noises more of an issue.
The reason the pistons have to face in one direction (the arrow) is that the
pin is slightly offset to avoid piston slap noises. Honing the cylinders
even a couple thousands will defeat some of this and piston slap noises will
prevail. In the past year I have come across three newly rebuilt Waterboxer
engines that made these noises just above idle.
If you really think the case is usable and you don't want practice changing
engines consider getting a new P+C set. Although they come with rings. You
may also want to consider "Total Seal" rings. You can also by the 2nd ring
from them. Their 2nd ring is a two piece gapless design. This virtually
eliminates blow-by losses.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Joe Luther
Sent: Saturday, February 19, 2011 6:22 PM
To: vanagon@GERRY.VANAGON.COM
Subject: air cooled piston weight/cylinder question
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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