[Vwdiesel] pulling pistons for bearings and rings

[James Hansen]

Well Will, I know you are concerned with doing it right.  Is this a bandaid
job to get by or one you are looking for long term use from?
For long term use, I would be inclined to bore and use new pistons.  If the
ridge at the top is indeed all carbon, it isn't so bad, but if it's a wear
ridge, you can be ouside the wear tolerance, and oil consumption will resume
after a while.. not immediately, but after a while.

For me the issue is the intermediate shaft bearings.  I would be comfortable
with re-using the crank bearings, but those damn intermed shaft bearings are
not that visible.  If you can pull the intermed shaft and inspect them, you
can judge then.  They have a habit of wearing, then losing too much oil
volume on higher mile motors.  Once the motor is back in the car, it has to
come back out to install the intermed  bearings- which are like a cam
bearing in a v-8, and a machine shop type install if you don't have a cam
bearing installer with an assortment of mandrels.

My race motor uses very expensive main and rod bearings, I reuse them every
second season, but check them on teardown with a dial bore gauge, not
plastigauge. Plastigauge is sort of accurate, but measurements are more so.
If you had cylinder measurements, you would know more.  Maybe if you go to a
shop for intermed shaft bearing installation, they can measure the bore and
you can decide from there whether to punch it out or just ball hone it and
re-ring.

To get the pistons out, use some scotchbrite on just the top part of the
cylinder to remove the carbon, and see if it's a metal ridge that's in the
way as well.
-james

> -----Original Message-----
> From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com]
> On Behalf Of Will Taygan
> Sent: Sunday, May 17, 2009 11:28 PM
> To: vwdiesel at vwfans.com
> Subject: Re: [Vwdiesel] pulling pistons for bearings and rings
> 
> Thanks for all the input.
> 
> To clarify, the engine is OUT of the car, on a stand, but the bearings
> are within new specs, so I was thinking of taking a shortcut and just
> popping in some rings, rather than pulling the crank.
> 
> But it seems that to replace the crank seals I need to pretty much pull
> the crank anyway, right?
> 
> The pistons are sticking on the carbon at the top, so they aren't
> coming
> out easily.  Give them whack?  Where's a good spot?
> 
> I'm thinking the bore/pistons are good, but since it was burning oil
> there may be a broken ring?
> 
> Trying to do it right, but also not redo stuff that's still good.
> 
> Engine will be going into a 82 Westy, so it'll have quite a bit of
> stress on it.
> 
> ** SO..... should I pull crank and have a shop hone/clean or flip it
> upside down, pull pistons and run a little rental hone in the
> cylinders?
> **
> 
> And if the bearings look good and are within new specs, is there a real
> reason to put new ones in?
> 
> Thanks, Will
> 
> On Sun, 2009-05-17 at 18:39 -0500, dieseltdi at verizon.net wrote:
> > If it were me, I would run a dingle ball hone or some 220 sand paper
> > across the ridge first but then take the pistons out through the top.
> > You can leave the crank in .  I have rebuilt 2 diesels still in the
> > car this way.  Hayden
> >
> > On May 17, 2009, at 10:59 AM, Will Taygan wrote:
> >
> > > The old pickup 1.6NA is torn apart on the stand.  It was burning a
> ton
> > > of oil, smoking and starting to run away.  I was expecting to do a
> > > full
> > > rebuild.
> > >
> > > (Engine was running when pulled)
> > >
> > > The valves in the head are very loose, and the exhaust ones are
> quite
> > > worn.
> > >
> > > As for the block, there's just a little carbon at the ridge - I can
> > > catch my fingernail on it - but not much else.  I can still see
> > > hatching
> > > in the cylinder.
> > >
> > > The block has an official VW reman sticker on it, makes me wonder
> what
> > > size bearings and pistons I've got.
> > >
> > > I pulled #3 main, and the green plastigauge says it's within specs
> for
> > > NEW bearings.  I pulled the #1 rod bearing and the green
> plastigauge
> > > says it too is within specs for NEW bearings!
> > >
> > > I suppose I should pull all the caps and plastigauge them, but...
> > >
> > > At least I'd like to throw on new rings while I've got it apart.
> > >
> > > According to the book I've got to pull the crank to get the pistons
> > > out.
> > > (and according to my mechanic buddy, I should pull it before honing
> > > the
> > > cylinder wall anyway)
> > >
> > > Or is there a way to pull the pistons out the top and run a quick
> hone
> > > in the cylinder?
> > >
> > > This is my first try getting into the engine guts.
> > >
> > > Thanks,
> > >
> > > Will.
> > >
> 
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