Thread: 300tdi flogged dampener and crank

Hi,

I think I've posted about this before........... had a similar issue with a 302W, but it was the cam sprocket key on the crank.

Was nowhere near as bad as yours, but would not run. Mostly stuffed key with a bit of flogging in the crank. In those days it was looked after by pro's. New key and some Loctite bearing seat compound in the keyway and all was good.

good luck, DL

Hi again,

What is wrong with an obvious tack weld between the balancer and crank?

Balancer won't move, and there is no disguising the prob.

DL

Originally Posted by BilboBoggles

I've had a similar issue but on a V8. Not sure if the repair will work in the same way on a diesel, perhaps not. But I found this page that documents a similar process to the one that was used on my V8.

Crankshaft keyway repair (Eric Perozziello)

The larger key has held for nearly 10 years of infrequent use - perhaps 50kK. The repairer who did it unfortunately is no longer around.

Originally Posted by That link

). OVERSIZE KEYWAY/KEY KIND OF REPAIRS:

"Machine the crank and balancer for an oversize key."

"Machining the crank for an oversize key is easy. In the
balancer, it's a different story. Maybe a flat file on
edge..."

"Cut a second keyway in the crank/balancer on the other
side of the crank and balancer. IE: a secondary keyway,
placed elsewhere around the crank"

"Machine a new woodruff key that fits the damage in all its
bumps and waves. You may want to clean it up a little bit
first, making straighter sides, and then use modeling clay
to get an impression of the hole."

"Clean up the damaged area to be flat faced, and then machine
a steel insert to fill in this space, flush with the crank
surface... Then use the standard key. I used this repair once,
and it lasted six years, and it was still holding fine when I
sold the car."

*** This is close to the repair technique I decided to use. (Ya
can't argue with successful practical results!). Now the problem
was how to cut the keyway without removing the crank. (see below)


IMPLEMENTATION: Cutting an oversize key, or cleaning up the damage.

"Use a key cutter from a milling machine, mounted in a hand
drill."

Machinist: "It'll never work. The key cutter bites in, and it
will throw the drill (IE: Chatter). You could never hold it steady
by hand, it's too wild- use an abrasive....Silicon Carbide."

"Abrasives/Grinding will overheat the crank locally, and cause similar
problems to the ones you'd have if you tried to weld it."

Machinist: "Grinding it slowly with a small hand grinder will
not do any harm. Just stop frequently and check your measurements
so you don't end up with a sloppy cut."


WHAT I DID:

I ended up getting a new key, a new balancer, and a modified
woodruff key to fill in the damage. I used a small die grinder
with a silicon carbide bit to cut an enlarged keyway in the
crank, cleaning up the damage. I then modified a woodruff key
to fit into the "cleaned up" part, but not extending above the
crankshaft surface (flush with it). Then the correct sized key
was able to fit in its normal position. The modified woodruff
key was simply a steel insert to fill in the "cleaned-up"
damaged region. I then used some Epoxy (JB-Weld) to hold
the modified key in place. The epoxy is not critical, so if it
fails, the steel insert will still be doing the job, but
it sure made installation a lot easier. I then tightened the
center-bolt very tight, since this will remove much of the load
from the repair zone.

thats more or less how we did it BUT we used a portable magnetic base grinding jig to hold the grinding tool, we also used a water soluable base lubricating oil as cutting fluid.

Originally Posted by horgan

NOFUSS - how long has that patch job of yours lasted? It was for the 300TDI balancer pulley? Sounds worth a try for now.

keep in toutch with the bloke for a year then he headed north so i thinks he still going. the hardest part was getting enough heat in there to do the job quickly. I had to buy big ass Oxy welding tip I use silver solder a lot as it hangs on real good if every thing is spicko clean. Get the solder to flow good there is no clean up after and pully comes of with ease. you will have to remover timing cover as the seal will cop it from the heat. At the end of the day this would still be a patch job you can not beat a new key way cut in.