[Vwdiesel] engine rebuild question

[James Hansen]

Oh man, I've seen bent valves.  
Bent valves, broken rod, destroyed piston, broken cam, head and crank all in
one.  T belt let go at a bazillion miles past service interval, just as
owner was gearing down, over-rev'ed the heck out of it at the time I imagine
to cause that. Turned to junk, only thing salvageable was the water pump
housing, 3 injectors, and the injection pump.

No such thing as it being for the best. You want your motor back running.
I would not want a shop that can't time a motor to do even a partial
rebuild/ re-ring.
The mechanic chap was surprised by a ridge on an 82 diesel?  Doh. A 28 year
old car has cylinder wear.  That ain't no news flash.
If it was me Dave, I'd tell the guy to give me back a car that is running,
and screw the ring job, that's just something else for them to screw up.
Reminds me of a trip to the rabbit hutch in phoenix years back. That still
makes my backside twinge. Run. Yes I'm a pessimist.   I have had exactly TWO
trips to a professional dealer shop turn out perfect IN MY LIFETIME, and I'm
46.  Maybe I'm a bad example, I'm sure there are perfectly good, perfectly
skilled and talented mechanics out there, but they always seem to be on
holiday when my stuff shows up.
Another thing.  Just how in the hell did he know the compression was low
AFTER he bent the valve?  Procedure is to test on warm engine.  By the time
all ten thumbs bend the valve, it's cold, and you get to test only three
then, cause one has a bent valve, and yes, the compression will be lower,
cause it's cold.
Did it start well?  That's the best test. If it started well, didn't use
oil, I'd leave well enough alone.
-james 


> -----Original Message-----
> From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com]
> On Behalf Of Tony and Lillie
> Sent: Tuesday, June 15, 2010 7:33 PM
> To: vwzoo at yahoo.com; vwdiesel at vwfans.com
> Subject: Re: [Vwdiesel] engine rebuild question
> 
> He is right about the ridge, that is something that is common on higher
> milage engines. Basically, the top ring stops about 1/4" below the top
> of
> the cylinder, and that is where the wear stops. So, there is a ridge
> that
> forms at the top, where there is essentially no wear.
> 
> Not too sure how he bent a valve, as they are straight in line with the
> pistons, and they are flat top pistons. I've had them destroy the cam
> followers (customer cars) in the past, but never have I seen a diesel
> with a
> bent valve. This includes the TDI engines.
> 
> I'd agree, have him do the rings with whatever size is in there now,
> after
> he hones the glaze off the cylinders.
> 
> Tony
> 
> ----- Original Message -----
> Subject: [Vwdiesel] engine rebuild question
> 
> 
> > Hi,
> >
> > I took my 82 diesel Rabbit to a local VW mechanic to adjust the
> injection
> > pump timing as I just couldn't get it to run quite right. In the
> process
> > of attempting to adjust the timing some how they bent one of the
> valves.
> > He called and told me that it was really for the best as the engine's
> > compression was real poor and it needed new rings. He said he would
> fix
> > the head as it was his mistake and he would cut me a deal and change
> the
> > rings for about $300 to $400 dollars. I called him today as it's been
> a
> > couple of weeks and he told me that cylinder walls have ridges in
> them and
> > that the engine had been rebuilt before and that he doubted if he
> changed
> > the rings he couldn't guarantee the engine. So my question is, is he
> right
> > with the ridges in the cylinder walls is that true, or is it a  thing
> > where oversize rings, new pistons or something could work.
> >
> > Thanks
> >
> > Dave
> 
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