[Vwdiesel] Banana Rabbit--Bad news...

Mon Jan 31 09:48:50 PST 2011

Firstly with cam cover off look for screwdriver sized shim gaps under cam 
lobes as mentioned by someone earlier.
If there are a couple of bent valves, you could check that the lifters are 
OK.

Also check the valve guides by rocking the valves. [Head now off]
.
Also drop one of the other good valves in a bad valve spot, to further check 
that valve guide for damage.

One way to check 'apparently' good valves whilst still in head, but with 
head off and upsidedown, is to drop kerosine onto each shut valve to see if 
they are seating correctly.
Removing cam and lifters will help.

Tapping valve stems with a hammer can test their seating.

Mark

----- Original Message ----- 
From: "Dave Cook" <davevw at yahoo.com>
To: "VW Diesel Group" <vwdiesel at vwfans.com>
Sent: Monday, January 31, 2011 5:20 PM
Subject: Re: [Vwdiesel] Banana Rabbit--Bad news...

Since the wonderful ice and snow storm has moved into the area, I have less 
to do with work.  So that means that I can spend some time with the car this 
evening.  We shall see what happens.

So, lets presume that there are a couple bent valves.

Can I just order some valves and seals and replace them?  Will I need any 
special tools?  Is this something I can do without having to rely on a 
machine shop-assuming there aren't any signs of warpage?  (The only one in 
town screwed up a part for me a couple years ago and still charged me for 
it.)

Dave Cook

--- On Mon, 1/31/11, Val Christian <val at mongo.mongobird.com> wrote:

> From: Val Christian <val at mongo.mongobird.com>
> Subject: Re: [Vwdiesel] Banana Rabbit--Bad news...
> To: vwdiesel at vwfans.com
> Date: Monday, January 31, 2011, 2:19 PM
> I had an 84 Rabbit which slipped the
> cam sprocket. I was getting off the
> expressway, and just pulling out of the stop sign. No
> thunk, no noise,
> except the other vehicles honking at me to get out of their
> way.
>
> Farmer friend was done with the girls for the afternoon, so
> he came and towed
> me home. I found that there was some movement of the
> crank, but there was
> definitely interference. So I pulled the head that
> evening. Two bent
> valves, and one somewhat dinged piston, the other just
> nicked.
>
> I replaced the valves, and all the valve seals etc while I
> was at it.
> Put it back together and continued to run it for years.
>
> I have seen a VW diesel, where the valve broke, and
> embedded itself into
> BOTH the piston and the head. I didn't get the full
> story on the
> symptoms, but it sort of fits your description.
>
> Either way, they are normally fixable. We'll all wait
> to see what
> you find.
>
>
>
> >
> > Well, if you get off with just changing the belt
> you'll have to change your
> > email to LuckyDavevw at yahoo.com
> .
> > Personally, my line of attack would be to pull the
> cam, then turn the engine
> > over and see if one cylinder is leaking excessively,
> or if you hear a lot of
> > whooshing in the intake or exhaust when you rock the
> crank. Another way
> > would be to use a leakdown tester, just let the piston
> bottom when you
> > pressure each piston up, watch for the turny bits as
> the piston goes to the
> > bottom. It's the surest way to check for valve
> collision damage.
> >
> > But, the crank stuck with accompanying noise event at
> TDC screams foreign
> > object which could be solid or liquid. Glow plug
> tip fall off? Oil build up
> > in the intake, then get slurped in?
> >
> > ...Insert brief interlude....
> > I got called away for a few hours, I like Loren's
> valve clearance checking,
> > but I do like checking for leakage, and it's an easy
> leakdown test when all
> > you're looking for is valves, and they are all closed,
> or supposed to be.
> > Turning it over with the glow plugs out is easy, and
> would be informative if
> > you can find a clunk.
> >
> > I've stripped the cogs on a belt too. Crank
> sprocket just eats them off
> > when the motor hiccups and it all starts to rattle,
> never had one go
> > kachunk, but it was uneventful. Quite the tense few
> hours until I had it
> > running again however.
> > -james
> >
> > -----Original Message-----
> > From: vwdiesel-bounces at vwfans.com
> [mailto:vwdiesel-bounces at vwfans.com]
> On
> > Behalf Of Dave Cook
> > Sent: January-30-11 9:37 PM
> > To: VW Diesel Group
> > Subject: Re: [Vwdiesel] Banana Rabbit--Bad news...
> >
> > Didn't think of stripped cogs. Dangit! The
> cheap car may have just turned
> > expensive!
> >
> > To clarify, I wasn't turning the engine with the cam
> bolt, I used the
> > sprocket hold tool to attempt to turn the
> sprocket. I didn't put much
> > pressure on it, I just wanted to see if it would turn
> backwards. I figured
> > if a piston was touching a valve in one direction, it
> would be able to turn
> > backwards the other direction a little bit. It
> did not but I may well have
> > been wrong in my assumption.
> >
> > I think I will be optimistic and say that maybe since
> the engine wasn't
> > running at a super high rpm that I'll be lucky and it
> will just need a belt.
> >
> >
> > Lets assume I pull the belt and find that the cogs
> stripped. I then pull
> > the valve cover and loosen the (intact) cam so all the
> valves close. =
> >
> >
> > If I am lucky and the engine can turn over loosly and
> freely, do you all
> > think I could get away with trying to retime the
> engine with a new belt and
> > see if it'll run? Will there be obvious signs
> that a valve bent for sure to
> > look for? (from above) If it runs, would you go
> ahead and drive it? I
> > guess I'm saying, is there any way I might possibly
> get lucky and not have
> > to pull the head?
> >
> > Interestingly, I noted that the TDC 0 is right at the
> center of the
> > inspection hole. Actually, I suppose it isn't
> that crazy. I guess that
> > means my likely candidates for bent valves would be
> cylinders 1 and 4,
> > right? I did think it was nice that a past owner
> marked TDC with white
> > paint so it was easy to find.
> >
> > Not sure when I'll get to look at it, it will probably
> be a few days. I
> > usually work 4 long days then take Friday off though
> the impending crappy
> > weather might change that.
> >
> > Dave Cook
> >
> >
> > --- On Mon, 1/31/11, LBaird119 at aol.com
> <LBaird119 at aol.com>
> wrote:
> >
> > > From: LBaird119 at aol.com
> <LBaird119 at aol.com>
> > > Subject: Re: [Vwdiesel] Banana Rabbit--Bad
> news...
> > > To: vwdiesel at vwfans.com
> > > Date: Monday, January 31, 2011, 1:11 AM
> > > =A0 I'm voting for an old belt
> > > stripped the cogs at the crank.=A0 :-(=A0 =
> >
> > > Pull the valve cover and release the valve spring
> tension
> > > (loosen cam =
> >
> > > bearings) then try again to turn it over (first
> be sure
> > > you've tried =
> >
> > > from the crank sprocket and see if the belt moves
> with ANY
> > > movement =
> >
> > > of the crank).
> > > =A0 Sounds like you might have broken the cam,
> bent
> > > valves, the usual =
> >
> > > that happens with a slipped/broken timing
> belt.=A0 Hope
> > > not but with =
> >
> > > oil in it, it's unlikely it threw a rod unless
> you'd
> > > already heard it =
> >
> > > hammering and seizing pistons don't tend to
> bang.=A0
> > > That just leaves =
> >
> > > the cam and valves.
> > > =A0 =A0=A0=A0Loren
> > > _______________________________________________
> > > Vwdiesel mailing list
> > > Vwdiesel at vwfans.com
> > > http://www.audifans.com/mailman/listinfo/vwdiesel
> > > =
> >
> >
> >
> > =
> >
> > _______________________________________________
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> >
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>
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