BXProject

[Bx Bandit]

Right, I have a mysterious rumble on the TD.
Facts: It has only started since I did the engine swap and gear ratio change.
The noise comes when cornering right and seems to come from the front n/s.
If cornering gently, the noise doesn't occur. If cornering hard, the noise is loud, harsh and mechanical with a definite mechanical beat, although this turns to more of a rumble at higher speeds (e.g when on a large but fast (20-30 mph) moving roundabout/interchange).
It's definitely something rotational and speed related. My initial thought was CV joint, but having swapped the n/s drive shaft with a known good one (and back again) there is no difference.
The wheel bearing feels and sounds smooth when turning by hand.
There is nothing rubbing.
The tracking is ok
The track rod end is the correct one and not worn
The lower b/j is good.
Wishbone bushes are good
Engine/box mounts are good
I have changed wheels between valver and TD with no effect (i.e. noise remains on TD)
Gearbox mods - what I did
The casing is a TD setup
The diff is from smiffys ZX box.
The diff casing is a TD setup (I think)
The tacho drive is the ZX setup
My thoughts
On pr-net there are two depths of recess for the tacho drive. If the ZX drive was the deeper of the two, this would in effect require a shorter o/s drive shaft. BUT, it would leak oil like a pissing horse wouldn't it as the faces wouldn't mate???? They are different ratios anyway so need to be swapped....
Are the splined ends that fit into the diff shorter on a ZX - so in other words mine is too long (a common complaint for me mind )
Could it be a cracked surface on the wheel bearing - only being noticeable under the forces exerted when cornering?

[jonathan_dyane]

I don't think driveshaft length is the issue, but could it perhaps be the driveshaft intermediate bearing?

[Vanny]

i'll buy in to the notion that size counts for nothing, but discount the idea that the intermediary bearing is at fault if the shaft has been changed!

I'd perhaps be looking for something brake related, though dont rule out a dodgy driveshaft!!!

You say rumble, can you feel it through the steering wheel? does the road wheel have play? I'll put money on something fouling, and as a result of something you have done during the engine change ratehr than the cog box change!

[jonathan_dyane]

Ah, but the o/s (long) driveshaft hasn't been swapped (or has it?)

[Vanny]

yes your quite right, nobby only seem to be looking at NS issues and rulling out the OS CV, still, the intermediary bearing is stationary and only whines, and does so regardless of the wheel direction

[Bx Bandit]

No, o/s drive shaft remains a constant. But why would it 'groan' on 'force related' r/h lock?

Road wheel has no play. Good question about feeling it through the steering wheel. My immediate response is that there is nothing at all obvious but there maybe subtleties I've not yet noticed.

Another thing I tried was doing the same cornering but on intermediate height setting but it had no noticeable effect................

[Philhod]

Rumbles spell brgs, always, almost

[jonathan_dyane]

No, o/s drive shaft remains a constant. But why would it 'groan' on 'force related' r/h lock?

Will the intermediate bearing not be subject to a load which is more out of square with the wheels turned? I could be talking complete shite tho, I've never had one let go yet (but have replaced one when it was something else causing the noise )

[Bx Bandit]

t'aint the intermediate bearing.......they rumble all the way to the jungle and back again. The rythm is more akin to a cv joint, but whilst the driveshaft/cv was fine before the op, something I've done has made it 'fucked' since...............

[docchevron132]

I assume the planet gear cage looked ok,and the planet gear bearings were all good?

If you find them sticking out of the bell housing soon then that'll answer it...

If it's a noise that only comes into being with a sideways force applied I'd be looking at wheel bearing myself.. Is the hub nut tight?

[Bx Bandit]

Yes the hub nut is tight. By the planet gear cage do you mean the 'thing' that holds the bevelled gears???? If so that's one thing I didn't check methodically. It's a big hunk of metal though - is it likely? The diff bearings had no roughness - would they display noise under force though - like when cornering just one way?
Thing with the wheel bearing is that it's smooth and doesn't make the usual noise associated with bearing failure. Possibly a cracked outer shell? But why now after the op?

[docchevron132]

I imagine the diff bearings themselves will be fine.
The planet gears (er, yeah, the gears in the cage on the side of the crown wheel) can and do explode.
It kills many a BE3 box.
Especially if they've been run for a long time with no oil in them..

That said, I happen to know the box the diff came from worked fine in that car, and certainly never ran with low oil whilst in J Dizzles ownership.

I duno, I'll come over and condemn it if you like?

[Philhod]

IT'S GOTTA BE THE WHEEL BRG ...he shouted......again.

The only other similar noise was when the inner end of the track rod had become loose.

Failed MOTas well on that

[Way2go]

IT'S GOTTA BE THE WHEEL BRG ...he shouted......again.

Wheels in British Racing Green eh?

[docchevron132]

standard shorthand for bearing that, all engineers know this!

[Father Ted]

all engineers know this!

[Bx Bandit]

/\ Sad but true! Why don't in rumble in anything but sideways force phil? I shall swap with a known good unit then. Damn frigging wheel bearings......I need a hydraulic ram!!

[mnde]

I know your pain. I've got a BRG just like that.

What's the difference between engineer's shorthand and txt tlk, btw?

Mark.

[docchevron132]

Oi you! coat...NOW!

Simple actually, txt tlk is used by morons, engineering talk is used by educated people!

BRGs are funny things Bandit..
If a purely rotational force is applied then the main force of the ball is directed in one plain only, if you apply a different force, like when cornering it alters the point of the bearing track where the force is applied then it can rumble if that part of the track is damaged / pitted / fucked.

That said it could be something else! Hard to say fo shizzle without actually hearing it really.

[Vanny]

To be honest the diagnostic process undertaken is very vague at best. I'm not convinced of it being a wheel bearing, they dont to suddenly fail, or suddenly become very loud. And while side load might increase the symptoms, i dont think they would increase as significantly as they appear to be doing.

I'd ponder that it might be a handbrake cable chaffing or something equally simple if the 'rumble' can't be felt through the wheel!