oil pump drive

[Cordoba16vt]

Ok i understand but why would you do that as cranks rarely fail , they are good as standard. A friend of mine uses 95.5mm crank 4 cyl at almost 9 000rpm...it is an old diesel one ...

[UrS4boy]

Ok i understand but why would you do that as cranks rarely fail , they are good as standard. A friend of mine uses 95.5mm crank 4 cyl at almost 9 000rpm...it is an old diesel one ...

I am quite sure that diesel cranks are forged to make them stronger than non-diesel cranks.

[Kieron20V]

They are all forged are they not?

Sent from apollo 13 using tapatalk

[jsol]

Both are forged. Revs play a part but you need to take into account the stress high boost places on the block, which in turn affects the crank.
Back OT I think nitriding of the crank could be the source of why the pump drive separated from the crank.

[Cordoba16vt]

My point of view is that Audi knows its job and cranks are strong enough to withold both revs and boost.No need to nitriding or whatsoever.

[mike74]

^^^ agree. All Nitriding does is effectively case harden the crank by up to about 0.006" deep...

[malncol]

ive received the new drive gear and its only 3 thou smaller ID than the old one which let go .Iam thinking I would need somewhere around 8 thou interference fit so ill have one made with smaller ID ?????
mal

[Error404]

Why don't you turn the crack nose down a couple thou?

[malncol]

making the crank smaller isn't what we want, it needs to be bigger! to make the drive tighter
mal

[Error404]

Ah yes right you are. Well I guess custom is the only way then?

[mike74]

You could maybe get the nose of the crank spray welded (HVOF) to build it up by a few thou'?

[malncol]

yes I could weld crank but iam trying not to remove crank as it means upsetting the gridle etc and the motor is allgood for now so doesn't need a rebuild

[quattro-nick]

i once replaced the drive gear on my crankshaft without problems,i just heated the drive gear and put into place and let it cool off
i dont know the measurements anymore
for the moment i driven about 1000km on street and track and it seems to hold
(fingers crossed)

[campbellWS]

Mal I'm at this same problem after getting my diesel crank back from nitriding. Thoughts were a new drive ring installed correctly would do, but to spin the drive freely by hand on the crank gave me the fear
What about a grub screw, drive ring drilled, tapped and a dimple on the crank ?

[jsol]

Broaching the crank for a woodruff key is another tried and true way but I think Mal wants to avoid opening the engine.