Date: Tue, 22 Feb 2011 15:29:39 -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: <031401cbd2ca$b98a81c0$6801a8c0@PROSPERITY>
Content-Type: text/plain; charset="us-ascii"
Scott -
Thanks for the opinion and information.
Type IV air cooled CV code engine.
Pistons are out of the cylinders with wrist pins installed, but kept with
the mating cylinders.
You keep referring to the John Muir book and I only have one for the Rabbit.
My air cooled version was lost years ago. I do now have a Bentley, though.
I plan on getting new rings and reusing the pistons and cylinders. If all
pistons were the same, I'd not be worried and never mentioned it but the +
marking and one being visually different concerns me. I can check piston to
cylinder bore clearance and piston/wrist pin weight and the ring to groove
clearance. Big ends of the rods are still on the crankshaft, everything
else is apart.
I'm planning on going very slowly and being extremely careful. I've been
cleaning and inspecting everything as I go along, today at lunch I tanked
and cleaned the fan housing halves. Next will be the tin. I would like to
paint everything before it gets reinstalled and the weather will affect
that. Actually, I have no choice but to go slowly having two kids and work.
What I would like at the end of the day is to have this engine get me around
a few summers while I gather parts to redo the other engine completely. I
probably jumped on this van before I was totally ready but it seemed to have
a lot of potential and a lot of spares, spares seem to be really important
in Vanagon land.
I'm still waiting to get it home. More ice yesterday and the driveway is
back to luge status.
Joe
-----Original Message-----
From: Scott Daniel - Turbovans [mailto:scottdaniel@turbovans.com]
Sent: Tuesday, February 22, 2011 2:57 PM
To: Joe Luther; vanagon@GERRY.VANAGON.COM
Subject: Re: Re: air cooled piston weight/cylinder question
re
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?
Type IV air-cooled right ?
the pistons and cylinders are not the weak parts.
The heads will likely fail long before much wears with the pistons and
cylinders and rings.
new rings are always a good idea ...mandatory in my opinion, if the pistons
have been taken out of the barrels, unless they are new. If used...new
rings.
you could check piston to barrel clearance. That's how loose or tightly the
bare piston fits in the barrel.
I would expect yours to be within spec. The pistons and barrels are not the
weak part at all.
the bottom ends are pretty good.
the heads are the weak area I believe.
if there isn't money for new pistons and cylinders..
the logical thing to do, seems to me is ....do a very careful good job of
assembling what you have.
With new rings.
it's a whole other step ...but one can remove the rods, inspect the rod
bearings, check oil clearance with plasticguage ( with new rod brgs
preferred...or the same used ones ..
but new rod brgs are not expensive )
if you know it has good rod bearings with oil clearance in spec ....and
new rod nuts or bolts, whatever is recommended there ...
and decent piston clearance and new rings ..
and fresh valve work ....you'll be fine.
and if they idea is to make it 'the perfect near racing grade engine that I
won't have to touch for 8 years" ..
that's not practical since the need to keep expenses down has been
expressed...
so just do a careful good job.
If I was very worried about that one piston ..I'd compare weight with the
other three..
( have you read John Muir on piston balancing in the Idiot's Guide ? ..you
should ) .
Make sure the odd piston is with its barrel if possible, of course.
now don't tell anyone this ...
( I hesitate to tell people my various unofficial tricks I've used over the
decades as people who don't know better might thing ..since everything is
not ALL NEW and perfectly machine shop balanced etc etc ) that long ago .
and several times I have used a not perfectly matching piston .....
carefully fitted to it's barrel, and with new rings and very careful
workmanship ..
and it worked just super fine for years and years.
I even , when I really fuss over some little thing ....I even imagine years
in the future and saying 'oh yeah.....I forgot all about that, that little
aspect I was worried about."
so if you're trying to keep costs down ..just do good careful work with what
it there ...
it's like this ..
if it doesn't work out this engine ..
it is far far more likely that some careless ( no reflection on you ...just
reporting on what I see,..in litterally hundreds of not a thousand engines
) ...far more likely that some workmanship carelessness will lead to a
problem than one piston is .0001 grams lighter or heavier than the others.
clearances are important ..
those you need to check carefully, in all aspects ...rings in piston ring
grooves, piston in barrel, rod bearing oil clearance if you do that far into
the engine ....etc/
Believe me ..it's in the Workmanship...that's where you get your results.
The parts matter..
and have to be decent and useable ...but the parts themselves don't matter
that much compared to really great workmanship,..within reason of course.
so get started on it already !
lol.
Scott
www.turbovans.com
----- Original Message -----
From: "Joe Luther" <jluther@ALFONS-HAAR.US>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, February 22, 2011 9:16 AM
Subject: Re: air cooled piston weight/cylinder question
> 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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