[Vwdiesel] Engine parts everywhere! :-)

Shawn Wright swright at zuiko.sls.bc.ca
Sun Jun 6 12:15:32 EDT 2004


On 6 Jun 2004 at 11:27, LBaird119 at aol.com <LBaird119 at aol.com> wrote:

> I was surprised at how good the rod bearings looked - no 
> perceptible sign of wear at all, although they are single layer, so it could be
> hard to spot. The crank bearings showed a bit of wear since I replaced them
> about 30k kms ago, but I suspect just from seating in. The #3 thrust bearing was
> down to copper on both sides, which I guess indicates the crank end play was too
> loose?
> 
>   My Rabbit's rod bearings were nearly like new with somewhere between 
> 100k and 150k miles on it.  At the end, one was bad from constantly losing oil
> and it sucked air too long in a corner.  There are sort of three layers to them.
>  First is a dull, very thin, soft gray.  Then there's a more shiny slilver with
> copper at the "oh crap" level.
>   Many to most of the thrust bearings I've seen showed copper.  Too much 
> time sitting at lights with the clutch in?  My Jetta had a REALLY stiff 
> clutch 
> pedal so that may have been part of why the thrust failed on it.

I guess I'm thinking of the wbx rod bearings, which I've been warned about - I expected 
them to be way more worn, but they all appear to be still on the dull grey layer.

> > 
> > I could not detect play in the int shaft, although it is stiff to turn... I
> > have suspected these bearings for years, but I guess a machine shop will have
> > to pull them?

>   They are usually still tight even when they're shot.  They tend to flake off
> and lose oil pressure.  With a long drift you can drive them out. In is a 
> little trickier as is making/keeping them sized so the shaft will still turn.

I fiddled with it last night, and realized the int shaft just pulls out :-)
Yes, the bearings are flaking apart, as expected. I was getting not much more than 
20psi at the head (hot) at 2000 rpm last I checked. The good thing is running for years 
like this doesn't appear to have damaged the other bearings.

> > 
> > Injection pump had some axial play - I could move the shaft in &out maybe 1mm
> > - this can't be good. The turbo bearing seemed tight &smooth.
> 
> 
>   IIRC the shaft does have some in/out play until the gear/pulley is 
> torqued down.  Turbos last a LONG time and usually have a little 
> side to side but should have no end play.

That could be it - I think I had already loosened the pulley at this point.
 
> > 
> > In all, it was a good morning of pulling things apart, but now I have a big
> > mess to clean up... and I need to start searching for a machine shop to hot
> > tank the block and replace the int shaft bearings, and rebuild the head for
> > me, or at least do a valve grind &new guides, etc. I saw no signs of head
> > gasket 
> > 
> > leakage, but it should be checked I guess. Do these shops normally measure the
> > bores also, or should I be looking to borrow the tools?
> > 
> 
>   Most shops should be able to measure the bores.  Checking for head gasket
> leaks entails staring at the gasket, looking for places in the metal ring, that
> show darkening or just a different look, indicating leakage.
>   You can r&r the valve guides yourself and save some money.  They're 
> easy to do too.  :)  I've found the exhaust valves usually need replacing 
> due to wear on the stems.  Of course disassembly takes a special spring 
> compressor.

I borrowed a set of telescopic gauges and a vernier caliper last night and checked the 
bores. The worst measurements were right at the wear limit of 3.015", with most at 
3.014 at the top and 3.013 at the bottom & middle. New is 3.0122", and I don't know 
how accurate my technique is. I popped one top ring off and slid it into the bore - the 
end gap was ~3mm, well over the wear limit of 1mm. Are new rings sized to fit into 
worn bores like this, so that I can achieve the optimum end gap of 0.3-0.45 mm? Or will 
I end up with too much end gap right from the start? I don't like the sound of that...
Also, all of the rings were at or near the side clearance specs. Is this generally due to 
ring wear, or is possible/likely that the grooves are worn too large? Is there any way to 
tell, aside from installing new rings?

I'll take a good look at that head gasket...--
Shawn Wright
http://Zuiko.sls.bc.ca/swright
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