Have you checked the Spigot bush in the rear of the crank for excessive wear? Also check the clutch disc to see if the centre has come loose and is letting the outer of the disc float about and when the pressure plate grabs the disc it may not be centered causing the vibration. I had both of these troubles when i had the Top Loader in my Hatch and we used to drive it way too hard all the time :-)
Bad Vibration in LX Hatch
Started by
_brodo_
, Jan 02 2012 08:24 PM
65 replies to this topic
#51
mick_in_oz
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Posted 15 January 2012 - 07:56 PM
#52
ls2lxhatch
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Posted 15 January 2012 - 08:25 PM
Uncancelled universal joint angles (pinion angle problem) make the tailshaft speed up and slow down every revolution. This can cause a pulsing vibration which could result in the tailshaft oscillating.Maybe a third possibility is that it is a pinion angle problem like some have suggested - but could that literally make the front half of the tailshaft oscillate by several mm, or would it be more likely to just mean irregular power is being delivered to the diff?
This is one of the better explanations I have read.
http://www.streetrod...gles/index.html
How to measure.
http://www.spicerpar...m/measuring.asp
Edited by ls2lxhatch, 15 January 2012 - 08:26 PM.
#53
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Posted 16 January 2012 - 07:20 PM
Alrighty, so we took the extension housing off and ran the dial indicator over the output shaft.
On the flat section where the speedo gear sits there was 0.1mm run out, but with the tailshaft on the splined section at the rear of the shaft (to give us a flat surface for the gauge) there was 0.6mm with one shaft, and about 0.5mm when I also tried the yoke off my old shaft.
By the time that gets to the uni joint and beyond - plus when it is under load - that could probably account for my few mm of oscillation I observed on the tailshaft when we ran it with the wheels off the ground. Hopefully this is the cause of all my grief.
Time for a reco'd gearbox. The car has an M21 in it, if I hadn't just got a new tailshaft made up and put the 2.78 centre in the banjo then I'd probably look at putting a T5 in it, but given it sounds like I'd need a new bellhousing and crossmember then I think I'm best off just looking for another M20/M21.
On the flat section where the speedo gear sits there was 0.1mm run out, but with the tailshaft on the splined section at the rear of the shaft (to give us a flat surface for the gauge) there was 0.6mm with one shaft, and about 0.5mm when I also tried the yoke off my old shaft.
By the time that gets to the uni joint and beyond - plus when it is under load - that could probably account for my few mm of oscillation I observed on the tailshaft when we ran it with the wheels off the ground. Hopefully this is the cause of all my grief.
Time for a reco'd gearbox. The car has an M21 in it, if I hadn't just got a new tailshaft made up and put the 2.78 centre in the banjo then I'd probably look at putting a T5 in it, but given it sounds like I'd need a new bellhousing and crossmember then I think I'm best off just looking for another M20/M21.
#54
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Posted 16 January 2012 - 07:54 PM
Have you checked the Spigot bush in the rear of the crank for excessive wear? Also check the clutch disc to see if the centre has come loose and is letting the outer of the disc float about and when the pressure plate grabs the disc it may not be centered causing the vibration.
Mick,
Yep cheers for the suggestion. I am not sure if it is related to my main problem or not, which seems to be road-speed based, but when I first got the car it had a problem that was like the clutch wasn't centreing properly. At speed the gear shifter would get a really annoying rattle, but if you'd clutch it a few times you could normally find a position where the vibration would settle down. So we'll have a good look at the clutch, plus change the noisy throwout bearing, while we've got everything out.
Cheers.
#55
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Posted 16 January 2012 - 08:11 PM
Was the few mill. osscil.just at slip yolk or was the ext.housing moving the same ammount.?
Bit hard to tell i know because the rear of g/box will shake in sympathy or vise vers.
Perhaps just fit a slip yolk to installed pos.and pull up and down on it at the yolk where uni. fits.
If you can move it the 4 odd mm as per the visual test the bush has serious problems.
If not then obviously its another fault,the o/p shaft usually does have some play for oil clearance
for the big bearing its hooked up to,,,and the further away from that bearing you go
the worse it gets,,i would have thought 2.5 th at the "flat,smooth" part of shaft would be ok.
Bit hard to tell i know because the rear of g/box will shake in sympathy or vise vers.
Perhaps just fit a slip yolk to installed pos.and pull up and down on it at the yolk where uni. fits.
If you can move it the 4 odd mm as per the visual test the bush has serious problems.
If not then obviously its another fault,the o/p shaft usually does have some play for oil clearance
for the big bearing its hooked up to,,,and the further away from that bearing you go
the worse it gets,,i would have thought 2.5 th at the "flat,smooth" part of shaft would be ok.
#56
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Posted 16 January 2012 - 09:18 PM
Hey NoBallsUC,
That was one of the things I checked - the extension housing wasn't perfectly stationary of course, but the oscillation looked very much like it was in the shaft not the gearbox.
Now that we have the extension housing off I think the output shaft bearing actually feels pretty good, the rear of the shaft doesn't give much at all to wiggling. But I think the shaft may be bent given the variation on the dial indicator. I have no idea how it got bent, I am pretty light footed and the gearbox is supposed to be only 30-40,000 k's since reco. Although, it is a bloody long way from that last bush to the end of the shaft.
It's interesting you say you think 2.5mm of play mid way along the shaft is okay. At 5000rpm I reckon it would make for a wild ride, but I may well be misunderstanding what you mean.
Regards.
That was one of the things I checked - the extension housing wasn't perfectly stationary of course, but the oscillation looked very much like it was in the shaft not the gearbox.
Now that we have the extension housing off I think the output shaft bearing actually feels pretty good, the rear of the shaft doesn't give much at all to wiggling. But I think the shaft may be bent given the variation on the dial indicator. I have no idea how it got bent, I am pretty light footed and the gearbox is supposed to be only 30-40,000 k's since reco. Although, it is a bloody long way from that last bush to the end of the shaft.
It's interesting you say you think 2.5mm of play mid way along the shaft is okay. At 5000rpm I reckon it would make for a wild ride, but I may well be misunderstanding what you mean.
Regards.
#57
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Posted 16 January 2012 - 10:39 PM
A less-determined person would have sold this demon-car long before now, so I applaude your efforts. 
It does keep pointing at the pinion angle being the problem, but I don't think it would show up at low RPM on jack stands. Normally a vibration shows up under load (either accelerating or decelerating), not when on stands.
You sure do have your hands full with this problem. It's going to be a huge relief when you fix it.
I just had a thought...... You don't have a split in your gearbox mount rubber do you? I had one once that wasn't split all the way, but the vibration was similar to what you have descibed. My wife just reminded me of it (be funny if she's right!).
It does keep pointing at the pinion angle being the problem, but I don't think it would show up at low RPM on jack stands. Normally a vibration shows up under load (either accelerating or decelerating), not when on stands.
You sure do have your hands full with this problem. It's going to be a huge relief when you fix it.
I just had a thought...... You don't have a split in your gearbox mount rubber do you? I had one once that wasn't split all the way, but the vibration was similar to what you have descibed. My wife just reminded me of it (be funny if she's right!).
Edited by Big Rob, 16 January 2012 - 10:42 PM.
#58
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Posted 16 January 2012 - 10:40 PM
I can be a bit foggy at times i know but what i meant was that if you measured .1mm of runout at where it was
measured near speedo gear it equates to around 2.5 thou... that would be acceptable considering the distance from
the bearing because the ext. bush with yolk in would "take up" the rest of slak.
2.5mm at the speedo drive would be a major.
Going on the .5mm runout at yolk sounds like the shaft may be bent.
These boxes have been round for a while & who knows what they have been thru.
Sorry for the confusion
,hope you get it sorted.
measured near speedo gear it equates to around 2.5 thou... that would be acceptable considering the distance from
the bearing because the ext. bush with yolk in would "take up" the rest of slak.
2.5mm at the speedo drive would be a major.
Going on the .5mm runout at yolk sounds like the shaft may be bent.
These boxes have been round for a while & who knows what they have been thru.
Sorry for the confusion
,hope you get it sorted.
#59
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Posted 18 January 2012 - 07:37 PM
Well more progress today. I took the day off to drop the gearbox off in Tamworth. I also thought to take my new driveshaft back to the manufacturer just for them to double check that it wasn't the source of my grief, since a driveshaft problem would explain all my problems very nicely.
Turns out neither uni was properly centred and the shaft was off the scale on their balancing lathe. What a %$^$! The shaft was supposedly balanced before I first picked it up. Anyway they reengineered it and I saw it spun up before I left and everything looks really good now with no perceivable runout at all.
I still dropped the gearbox off, but now they'll just put the mainshaft on the lathe to make sure it is not bent, and check the bearings, rather than replacing the lot. Hopefully I can pick it up on Monday.
With any luck when I get this thing back together all my problems will be sorted.
Turns out neither uni was properly centred and the shaft was off the scale on their balancing lathe. What a %$^$! The shaft was supposedly balanced before I first picked it up. Anyway they reengineered it and I saw it spun up before I left and everything looks really good now with no perceivable runout at all.
I still dropped the gearbox off, but now they'll just put the mainshaft on the lathe to make sure it is not bent, and check the bearings, rather than replacing the lot. Hopefully I can pick it up on Monday.
With any luck when I get this thing back together all my problems will be sorted.
#60
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Posted 18 January 2012 - 08:02 PM
Hope they didnt charge u for the tailshaft fix up!
I would be frokin spewin at that bullshit.
I have shortened 3 tailshafts and not had a problem with one.
We dont even have a balancing machine!,but i guess its not exactly rocket science when
you index everthing before you start cutting then tru the slight runout after welding the ends in.
Lathes and dial gauges are wonderfull machines.
good to see you found the prob.
I would be frokin spewin at that bullshit.
I have shortened 3 tailshafts and not had a problem with one.
We dont even have a balancing machine!,but i guess its not exactly rocket science when
you index everthing before you start cutting then tru the slight runout after welding the ends in.
Lathes and dial gauges are wonderfull machines.
good to see you found the prob.
#61
_SS Hatchback_
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Posted 18 January 2012 - 08:18 PM
i had the same issue when chasing my vibration aswell. had the shaft balance and they said it was bent , so i though woohoo only to still have the same issue. After another few weeks of chasing the issues had it on hoise and running and seen shaft still bent like a banana, took it back and they said no its all good , just humour me guys so they tried it again and sure enough bent again tried blaming me for hitting speed hump or something but anyway had a new one built instead from other company thinking it should sort my dramas but it settled them but not got rid of the vibration, thats why i mentioned checked centreing before and unis although new can still be rooted which was the case with my shaft . Lesson is even though its new it could still have a problem....
Mine still ended up getting most of the problem with angles but keep going as when you get it you will be stoked, its a total new enjoyment driving it when you sort it out stick with it as it took me ages until like you i dedicated a few weeks to it then sorted it . Also may pay to reread the whole thread as it might bring up something someone mentioned again that may help . The dial gauge i mentioned to you before was to check the axle too, remove the wheel and dial it in on your hub and see how much movement you have incase it was bent on a gutter ???
Mine still ended up getting most of the problem with angles but keep going as when you get it you will be stoked, its a total new enjoyment driving it when you sort it out stick with it as it took me ages until like you i dedicated a few weeks to it then sorted it . Also may pay to reread the whole thread as it might bring up something someone mentioned again that may help . The dial gauge i mentioned to you before was to check the axle too, remove the wheel and dial it in on your hub and see how much movement you have incase it was bent on a gutter ???
Edited by SS Hatchback, 18 January 2012 - 08:19 PM.
#62
_fryzem_
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Posted 18 January 2012 - 09:01 PM
have you made sure you dont have a bent axle??? maybe someone clipped a gutter in it at some stage
#63
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Posted 19 January 2012 - 08:16 PM
Gee Rob, sounds like you had a painful process too.
I didn't stick the dial indicator on the axle flanges, but we did have a close look at the wheels spinning when the car was running on stands and they both seemed spot on. But if I still have any lingering vibration I'll certainly take a closer look at that.
So the gearbox place rang today, my mainshaft is absolutely perfect, but the output bush was completely flogged out. Little by little I hope we're gonna nail this vibration!
I have a few other questions, but since they aren't really to do with this vibration I'll start another topic.
I didn't stick the dial indicator on the axle flanges, but we did have a close look at the wheels spinning when the car was running on stands and they both seemed spot on. But if I still have any lingering vibration I'll certainly take a closer look at that.
So the gearbox place rang today, my mainshaft is absolutely perfect, but the output bush was completely flogged out. Little by little I hope we're gonna nail this vibration!
I have a few other questions, but since they aren't really to do with this vibration I'll start another topic.
#64
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Posted 21 January 2012 - 09:24 AM
yeah mate , i think i had a few issues and slowly each one got it better , my biggest was the angles but all cars are different. My problem also was that because of the angles they flog out uni's and vibrations slowly make other things loose so you see where you end up chasing your tail sometimes. Anyway seems like your onto a few things hopefully it will be your issues
#65
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Posted 21 January 2012 - 07:10 PM
So with regards to angles. My big outstanding question is what engine mount plates to use.
The car had the HQ plates on it, but the problem is that the lower engine meant I needed to pack about 10mm of spacers under the xmember bolts in order to create clearance for the driveshaft. It's pretty ugly.
I spent the money and bought the replica Torana plates off ebay, so I have them sitting there ready to go. I'd really like to put the Torana plates on to do away with the spacers on the xmember, but I don't want to aggravate and potential problem with the pinion angles.
The car is really quite low. From what I have seen in this thread a lot of people with lowered cars use the HQ plates, but then they don't have M21's, and they seem to have custom xmembers for whatever gearbox they have.
Any suggestions on the best way to proceed would be appreciated.
I'm still waiting on the gearbox but I got a whole bunch of other things sorted today. Will be great when I get this thing back together (I hope).
Cheers.
Edit: I guess I am asking: Anybody else with a lowered LX and M20/21 box with standard crossmember, what engine mount plates to you run?
The car had the HQ plates on it, but the problem is that the lower engine meant I needed to pack about 10mm of spacers under the xmember bolts in order to create clearance for the driveshaft. It's pretty ugly.
I spent the money and bought the replica Torana plates off ebay, so I have them sitting there ready to go. I'd really like to put the Torana plates on to do away with the spacers on the xmember, but I don't want to aggravate and potential problem with the pinion angles.
The car is really quite low. From what I have seen in this thread a lot of people with lowered cars use the HQ plates, but then they don't have M21's, and they seem to have custom xmembers for whatever gearbox they have.
Any suggestions on the best way to proceed would be appreciated.
I'm still waiting on the gearbox but I got a whole bunch of other things sorted today. Will be great when I get this thing back together (I hope).
Cheers.
Edit: I guess I am asking: Anybody else with a lowered LX and M20/21 box with standard crossmember, what engine mount plates to you run?
Edited by brodo, 21 January 2012 - 07:12 PM.
#66
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Posted 30 June 2013 - 12:32 AM
Any suggestions on the best way to proceed would be appreciated.
I'm still waiting on the gearbox but I got a whole bunch of other things sorted today. Will be great when I get this thing back together (I hope).
Cheers.
Edit: I guess I am asking: Anybody else with a lowered LX and M20/21 box with standard crossmember, what engine mount plates to you run?
G'day I'd be interested to find out if you solved your problem. After reading your troubles , are you still on here
Cheers
Morro
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