1.9 Stripped Crank Key!

[commuter boy]

So the Passat had jumped time, twice.

Just a half tooth or so, not enough to bend anything, just enough to make it run poorly.  Re-time, scratch head, write it off the first time to not tightening the cam pulley enough or some other error.

But twice?  No.  Time to strip it down.

Harmonic balancer (old type) had gear tooth marks on it, with some play.  Uh-oh.  This doesn't look good.

Pull the crank sprocket, and there's only a fingernails width of the "key" left.  And of course, the crankshaft keyway is widened out, but only on one side.

So I got a new crank sprocket, drilled two 1/8" holes through it, and the crank, and am going to epoxy in some locating pins and epoxy up the fretted keyway in the crank and hope for the best.

How likely is this sort of repair to hold?  I'm thinking the pins (drill bits cut to length) should be enough to keep the crank sprocket from walking, since the stretch bolt should take most of the load.

[Patrick]

Have to ask the other guys, but I think there's an update on the bolt. Any thoughts of using an oversize key and machining it to fit?

[commuter boy]

The previous owners had put the upgraded bolt in, but didn't replace the balancer to the upgraded part.  I have a suspicion they threw the new bolt on
as a bandaid to the crapped out crank and sold it straightaway.

I'm amazed I drove it for a few months without all heck breaking loose.

The "key" is cast/forged into the crank sprocket, so oversizing it would be a pain, as would be working on the crank stub sticking out of the engine.  I realize machining the crank end to match the new "D" shaped TDI crank sprocket keyways would be the ideal fix, but it's a little hard to do perfectly when lying on a concrete floor under the car.

[Patrick]

Yup! You probably came up with the easiest fix! I wonder if a little "JB Weld" in the keyway when you put it back together would be a good thing. Locktite makes a "bearing lock" that's supposed to be good for 10 thou too. Might be enough if caught early enough.

[commuter boy]

Already ahead of you on the JB weld in the worn crank keyway  

And some on the pins as well, to make up for any play and to prevent them from backing out, and the high temp red loctite for the bolt.

Wonderful stuff that epoxy, but I don't think the bolt's coming out ever again.

[Otis2]

If you're going to go with the pin idea, I wouldn't use drill bits.  They are too brittle and easily broken.  Cut a narrow diameter bolt down to size instead.  Good luck.

[chrissev]

if it jumped time the head's probably already f*cked up.  You'll more than likely have some valve issues in the near future.  Just warning you

[fatmobile]

I've heard that they had the same problem with the G60s and people who have tried this solution ended up with the end of their crank split out because the pins weakened it.
 Anyone else heard this?

[QuickTD]

I've heard that they had the same problem with the G60s and people who have tried this solution ended up with the end of their crank split out because the pins weakened it.
Anyone else heard this?

Yes, I've heard of this. Thats why I don't believe in cheating. To fix it right the crank really should come out and get welded/machined to take a TDI pulley. Reassemble with a new bolt torqued to spec and a one way clutch alternator pulley then forget about it forever.

[commuter boy]

if it jumped time the head's probably already f*cked up.  You'll more than likely have some valve issues in the near future.  Just warning you

Possibly.  It just slipped enough that it was still running, albiet with a rough idle and tons of smoke.  Doesn't seem to have been any contact.  Now that it's back together and timed it runs like a clock.

I'd obviously prefer to pull the whole engine out and machine the crank, but it doesn't make any financial sense at this point.   If I get another few years out of it I'll be happy.

My dad did one like this five years ago, and it's still on the road today.  I'll post up if it expires prematurely

I have some pics of what was left of the crank sprocket, and the marks on the balancer if anyone's interested.

[TD Westy Guy]

I am on my 4th new gear.  :evil:
The first one went after I had the AAZ installed for 1 year in my 82 Westy . Its a 1993 Passat Eco-Diesel (Canadian TD).
I got an OEM Gear and Bolt which lasted about a month. I went to start and heard a really bad "Tink" sound of metal on metal.  :shock:
After the tow home, I got it appart and discovered the key was sheared completely. I replaced that one with VW Gear/Bolt and it has lasted since 25 July 06. I used JB weld to fill the worn keyway and there is no sign of any left after the recent removal.  Two days ago the same symptoms of problem showed up again. No power and chokes when you accelerate.
Its apart again and I am trying to figure out what to do this time.
Does anybody know whats involved with the  upgrade to the TDI Harmonic Balancer and TDI Gear?

[commuter boy]

Was the keyway in the crank worn?  If it was, I would expect it to quickly wear down the key.  I wouldn't expect JB weld to make up for a worn keyway.

How much wobble was there when you did the install?  Sometimes you need to shim the harmonic balancer to get it smooth, or replace it with another till you get one that's just right.

Did you use the correct torque procedure for the bolt?  How'd you hold the crank in position while you tightened it?  Use any loctite?

I imagine the fix if you've covered all the above is pulling the crank and having it properly welded and machined to a TDI sprocket.

[wyldman]

The crank has to come out,and be properly welded up,and remachined to accept the TDI gear.

Getting the crank out is the hard part.

Once it's out,find a place that can repair it,and it will never happen again.

I have done quite a few for the members here if you cannot find anyone local to do it.If your crank is standard,I have them in stock on the shelf ready to go with a new gear.