The old Crown Wheel and Pinion whining questions...

[Jezza_hr]

I've had a look around and I've found two topics that somewhat contradict one another when looking for the answer to this question.

I just had my crown wheel and pinion replaced after my last one blew up (everything thoroughly cleaned, bearings replaced and backlash set). There are two things I have noticed after driving about 30 miles so far.

- The wheels are a little harder to turn by hand than they used to be. Would this be down to bedding in with the new crown wheel? Obviously there isn't much change when turning the prop by hand due to the weight difference etc

- There is a slight whining when coming to a stop (the sound of a vacuum cleaner being switched off) and when maintaining a consistent speed at about 30-40mph. Is this normal during the running in procedure or is something not right with the set up?

I also noticed around here there were running in recommendations for the crown wheel, which I saw AFTER driving the car admittedly the highest I've pushed it is 60mph so far, with a lot of general street driving (stop starts etc) and gentle acceleration to come up to speed. But I can't help but feel like a bit of an idiot for not adhering to this from the word 'go', would there likely be any damage or detrimental effects for my idiocy?

[jondee86]

Bearings will be be a little tighter than before due to pre-load. They will
loosen up a bit as they bed in. I don't even know the recommended
break-in procedure for a new CW&P, but gears always need a period of
light load running to burnish the mating surfaces and let them bed to each
other. So I would say just take it easy to begin with... no heavy torque
loading... just normal "granny style" driving for a while. Then raise the
rpms and a bit more loading by running thru the gears at less than full
throttle until you have 1000 km or so on the diff. Change the oil and start
load cycling in earnest

Cheers... jondee86

[Jezza_hr]

As always Jondee, your informative and quick responses are highly appreciated . The break in procedure I'm referring to is one that Irishtwincam has posted in a previous topic (along the line of: 30mph driving for the first 100 miles, oil change, a littler heavier until 500 miles, another change and carry on).

I'll change the oil at the end of the month for something higher grade and again at the end of February, hopefully it will all bed in with minimal noise. I just wanted to be sure that what I'm hearing/feeling is normal after installing a new CW&P set.

[jondee86]

Yeah... I just dug up those recommendations from 20Vwill... I knew I had
seen them somewhere Very detailed, and the cool down period is also
mentioned by some gear manufacturers. Most times that will happen as
you go and have a beer after your first test drive :-P

Cheers...

[allencr]

Jezza_hr Wrote:I just wanted to be sure that what I'm hearing/feeling is normal after installing a new CW&P set.

NO, it is not normal and does not need any specific running/bedding in and it will not get better, only worse or it will just stay almost the same for a looong time if its bad setup isn't too far off.
The new bearing's pre-load may have been setup on the high side so it will have some resistance for the first few hours or so. It will be generating some extra heat. Don't plan on climbing Pikes Peak or pulling a trailer for 1000km/600mi.

[Jezza_hr]

allencr Wrote:

Jezza_hr Wrote:I just wanted to be sure that what I'm hearing/feeling is normal after installing a new CW&P set.

NO, it is not normal and does not need any specific running/bedding in and it will not get better, only worse or it will just stay almost the same for a looong time if its bad setup isn't too far off.
The new bearing's pre-load may have been setup on the high side so it will have some resistance for the first few hours or so. It will be generating some extra heat. Don't plan on climbing Pikes Peak or pulling a trailer for 1000km/600mi.

So, wouldn't the bearings require a minor amount of bedding in to calm the resistance and noise?

[allencr]

Jezza_hr Wrote:So, wouldn't the bearings require a minor amount of bedding in to calm the resistance and noise?

Yes, they can use some run-in so don't pull a trailer the first 50k & change the lube at 1000k. There may be a VERY light paste like cover on the magnet, it's grey and doesn't look like the metal it is, more like some modeling clay. Anything more then that signifies trouble.
The noise you hear is not from the bearings if it is most noticeable during light throttle level ground cruising, it turns on & off with slight throttle changes, and disappears with heavier throttle.

[fax0815]

Did you buy a new Cw+P?
Reucing of an old one could cause this, too.

[Jezza_hr]

Yes, it's a brand new CW&P. I've spoken with both Weir and Darren McNamara. They have both advised me that this is likely due to pinion depth (or preload of bearings) so I'll be taking it apart again at the weekend to check it all through.