oil pump drive

[4WheelDrifter]

That is bad luck that the drive failed, but it's good that you caught it before doing major damage.
I've not heard of a pump drive fail like that before. Maybe they have never been pushed that hard before, as normally cars used in serious motorsport have dry sump systems.
What grade of oil are you using, what rpm limit do you use, and what sort of pressures do you see?

[UrS4boy]

Oil Pump, Temperature Sender, Pressure Relief Valve Info.

... surely I cant be the first to have this happen?? or is it just my luck. thanks mal

I have been on UrS forums since 1999 and this is the first oil pump drive failure that I remember being reported to a forum. I thought that they were bullet proof.

Oil Pump, Temperature Sender, Pressure Relief Valve Info:

http://forums.quattroworld.com/s4s6/msgs/93029.phtml

(Un-annotated photo courtesy of 4WheelDrifter (Stu) on the S2forum).

[Error404]

As above never heard of a failure. Is there some history there, I.e. It's been removed before and refitted incorrectly?
Good that you found it and there wasnt further damage caused

[Thuppu]

And the oilpump itself is ok, not jammed or the gears inside broken?

[Cordoba16vt]

Also what revs did the engine rev to? Can you post more photos of the failed parts

[malncol]

the oil pump is perfect and I cant really post pics of broken bits because there are none, its just the pump drive ring has came loose on the crank. Don't know if the ring has ever been replaced but I would dout that it has.
iam using nulon 10w60 full synthetic
engine rpm limit is 8200 but iam rarely up there so will be lowering it
oil pressure is apparently good and stable ,cant tell you what its running at because I haven't got the data
It appears iam just lucky to have this problem (doh)
thanks
mal

[4WheelDrifter]

The damaged part would still look like it does in Dave's photo:



(Nice annotations on the 'exploded' picture btw, Mr Librarian, Sir.)

8200 rpm is certainly high for a stock pump.
I wonder if the rapid and frequent speed change of the crank may have contributed to the drive failing. Although it's hard to imagine any difference in inertia between the crank and pump would hammer the drive loose. But Rallying is hard going.

It's an unusal failure, it would be nice to get to the bottom of it, although it's possibly unlikely to happen again, it's not something we want to risk really.
Having confidence in the engine and the car is everything.

[Cordoba16vt]

It would rather be the thick oil used, in combination of high revs and the rapid change in them if short gears are used. May cause a lock up of pump gear and hence the failiure. Just a thought, though.

[Kieron20V]

Did you have the crank heat treated in any way? Eg hardening after polishing journals or nitriding?

Sent from apollo 13 using tapatalk

[malncol]

yes the crank was nitrided but they seem to think that it would not have affected it, and yes rally is very hard on things probably more so than tarmac
I guess ill see if the new gear which I had to get from Germany will fit and pray to the rally gods it doesn't do it again

[Kieron20V]

I think youve found your culprit im afraid. My understanding is that putting the crank through a heat cycle high enough for nitriding causes the interference fit between the crank and the pump drive to loosen because of the different materials used. Ive spent the last 10 minutes looking, but Im sure I read one of the big 20VT builders in the states recommending that you replace the gear with a new one if having any heat treatment done on the crank for this exact reason.

[malncol]

Ok maybe you have the answer, so if we fit a new one up (providing the measurements are good) we should be ok??

[hammer]

This also happens by a friend of Mine after nitrided the crankshaft (also Bad vibration without vibration damper can make this happen) . You can fit it with hollow Pins to.

[Cordoba16vt]

This also happens by a friend of Mine after nitrided the crankshaft (also Bad vibration without vibration damper can make this happen) . You can fit it with hollow Pins to.

Can you please explain the proces of nitriding ... before I5 i come from 16vT VAG ( still own 460 WHP @ 7750 rpm GTX3076 turbo SEAT Cordoba converted to 4x4 by means of S3 GB and Haldex ) ,and never had any problems with standart 16v cranks to 8 500 rpm ? Same rod 144mm , same stroke 86.4mm ?

[hammer]

Can you please explain the proces of nitriding ... before I5 i come from 16vT VAG ( still own 460 WHP @ 7750 rpm GTX3076 turbo SEAT Cordoba converted to 4x4 by means of S3 GB and Haldex ) ,and never had any problems with standart 16v cranks to 8 500 rpm ? Same rod 144mm , same stroke 86.4mm ?

Its just a process to harden a Material. The good thing is that the Material get's bigger. The bearings at my crankshaft get 0.01bigger. Negativ is that it is banded after nitrided and the oil gear can turn of, because its a other Material than the crankshaft.