richard thomas
|
| posted on 1/8/06 at 07:52 PM |
|
|
Wot i done today...
Had a busy one today - not entirely pointless but....
Fed up of what i thought was excessive Diff noise so I decided to fit a replacement one to see if it would cure it.
Got underneath car, had a shake around and came to the conclusion that the nearside outer UJ was a bit suspect - took off the driveshaft and replaced
it with a spare i've got. Took car out - same noise.
Sooo...must be the diff after all, i thought. Took out my 3.62 LSD and fitted a 3.62 open diff...not without problems - shattered my torx drive bit
for the driveshaft bolts so had to go get a new one. Got back - rounded off three bolts where the drivshaft meets the diff. Ended taking out the diff
with the nearside driveshaft fitted. Heavy!! On a Luego the nearside lower wishbone needs removing to get out the lower diff bolt...more work
(sigh).
Fitted new diff - took car out - SAME NOISE!!!
Head scratching, thought of propshaft alignment. I have a Bailey Morris with a resilient tube. The centre bearing is a bit lower than the diff and
engine output flange (30mm lower than diff, 70 lower than gearbox flange - my fault from build..) so decided to shim it up as far as i could. Got it
midway between the two - took car out and - same noise
I am coming to the conclusion that i might have to live with this racket...but have learnt a few things today -
LSD Diff heavier than an open one!
My LSD is not knackered!
Driveshaft bolts should be replaced if head drives a bit suspect!
Halfords Torx bits break but they exchange them - no quibbles!
Still have a few questions though...
Does anyone have a BEC that doesn't make some transmission noise on a feathered throttle?
My gearbox output shaft is not in line with the diff flange i.e.it is off to the driver's side in the engine bay, but it is parallel to the diff
flange - is this a problem?
The centre bearing is attached to the front part of the propshaft and hence is on a slight angle (towards the gearbox flange) in the tunnel - could
this be a contributing factor?
Would a rubber doughnut in the propshaft make a better job than resilient tube of damping out what appears to be backlash or shunt in the drive
train?
When the car is in gear, the output flange can be turned by hand 2-3mm - is this normal. Surely there must be a bit of play allowable?
There is a similar amount of play at the diff - am i hearing the result of the play in both gearbox and diff when on feathered throttle? (It
disappears on acceleration or overrun but is very apparent when the clutch is dipped and the car allowed to coast at around 40 and above)
Am I just being a bit soft?
Finally, learned something else - with a lid on it doesn't sound half as bad but without a lid the rain don't half sting at 80!!! And it
still scares the sh*t out of me
All advice appreciated.
Cheers, Rich.
|
|
|
|
|
ned
|
| posted on 1/8/06 at 08:05 PM |
|
|
all the ones i've been in have had a few clonks and clatters..
beware, I've got yellow skin
|
|
|
gingerprince
|
| posted on 1/8/06 at 08:08 PM |
|
|
As they would say in the TVR world...
T.A.D.T.S.
(tey all do that, sir)!
If you don't want that noise, don't feather the throttle - boot it 
[Edited on 1/8/06 by gingerprince]
|
|
|
watsonpj
|
| posted on 1/8/06 at 08:28 PM |
|
|
drivetrain noise
My blade does the same and I've added a TRT which did slightly reduce the noise. I've also jack it up and run it up to see if I could work
out what the cause of the noise was. I also have a reverse box which has a neutral and you can hear some similar noises when you run it like that, so
I think a lot of mine comes from the backlash in the gearbox but the axle probably has a bit of a contribution hence the TRT. I was going to try some
sound deading foam in the tunnel see if that helped.
|
|
|
richard thomas
|
| posted on 1/8/06 at 08:58 PM |
|
|
If I could persuade myself it was normal I would feel a tad better.
How would you describe the noise you have? - Mines like a sort of clattering...
Rich.
|
|
|
watsonpj
|
| posted on 1/8/06 at 10:07 PM |
|
|
Clattering
Clattering would be a good description, especial when running at constant speed (ie motorway). I just took some video of the backlash on the prop with
1st gear engae and the reverse in neutral and you can hear the clatter on that. U2U me your email address and I send it on see if you think it
could be the same thing . I wish mine was only 2-3mm movement on the output shaft, mines more like 10-15 degress you can see it on the video. Is the
2-3mm without the propshaft on (ie not limited by the diff)? Maybe the BEC guys should get together and do a group buy on earplugs and sound deadening
foam
|
|
|
richard thomas
|
| posted on 1/8/06 at 10:17 PM |
|
|
Even though I said 2-3mm, it's probably more - I'm trying to kid myself i think...it is with the propshaft off though.
I'll forward mail address - looking forward to seeing it's not just me!!
Rich.
|
|
|
TimC
|
| posted on 1/8/06 at 10:30 PM |
|
|
Happy to come and give an opinion at some point?!
|
|
|
richard thomas
|
| posted on 1/8/06 at 10:37 PM |
|
|
Sure, Tim - when you around??
Be nice to know if you recognise the noise?
Rich.
|
|
|
OX
|
| posted on 2/8/06 at 12:02 AM |
|
|
mine makes more clunking noises than my r1 indy did ,i dont know if theres any more backlash in the gearbox on the busa but mine makes a right
racket.its not getting any worse tho even after the 180mile thrash round oulton park but at those speeds i didnt even notice it its deffo worse the
slower i drive ,specially through traffic.
|
|
|
DIY Si
|
| posted on 2/8/06 at 09:12 AM |
|
|
My Indy bird also does this. Gets slightly worse when the cars hot and it occasioanly does it regardless of throttle.
|
|
|
bimbleuk
|
| posted on 2/8/06 at 10:34 AM |
|
|
In a slightly similar vein. I have a similar type of noise/vibration in my transmission but I have a CEC. I was positive the diff was the source by
driving with and without a helmet and trying to pinpoint it.
However on a rolling road using headphones attached to a rod the diff was silky smooth and the GBX sounded like a "box a nails". I was
surprised at the difference even though outside the car it was diffcult to hear.
I've got an engine with very light internals and a very light ally flywheel but didn't balance them before fitting. So I'm not
ruling out the engine as the source!
I do have a clonk as well but I know thats the diff needing some more pre-load on the input shaft bearings.
[Edited on 2/8/06 by bimbleuk]
|
|
|
matt.c
|
| posted on 2/8/06 at 07:09 PM |
|
|
quote:
mine makes more clunking noises than my r1 indy did
Not surprising after the roundabout action!!!
Are you sure those noises wern't me?
|
|
|
richard thomas
|
| posted on 2/8/06 at 08:17 PM |
|
|
Have been out again tonight, and with a lid on it is bearable - just.
Plus you can't hear it when giving full throttle
Still don't seem right though....
Rich.
|
|
|
