Havnt had it personally, but a bent pinion of say .005" transferred out to the yoke several inches out will be .015 or so by the time it gets to the tail shaft flange, rough calcs done in my drunken head but you get the idea.
Cheers.
driveline vibration
Started by
_NYS 71_
, Nov 06 2011 08:03 PM
62 replies to this topic
#52
_NYS 71_
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Posted 21 September 2012 - 10:02 PM
i hear ya mate, bout the drunkin thing and yeah little bit bent at pinion by the time its out at the tailshaft means one pain in the ass vibration. not one i wanted to find but something im guessing has to be checkedHavnt had it personally, but a bent pinion of say .005" transferred out to the yoke several inches out will be .015 or so by the time it gets to the tail shaft flange, rough calcs done in my drunken head but you get the idea.
Cheers.
#53
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Posted 02 November 2012 - 06:07 PM
just a little update with my vibration..took the car to some "good blokes" mechanics workshop i know to check few things,we put the car on a hoist and...
-checked tailshaft runout again..front less than 5 thou..middle 8 thou..rear 25 thou
-diff yoke 1-2 thou runout
-rear rims runout (roundness) 5-10 thou..nothing unusual
-checked diff alignment to body(with borrowed tool from near by panel beaters shop)..spot on
-took car off the hoist and jacked up the rear on axle stands and took it up to 100 kays@3000 rpm to visually watch tailshaft and wheels ..nothing unusual that we could see apart from an out of round tyre but that was there before with old diff an no vibration
-took wheels off ..up to 100 kays again..vibration still there
-one of the guys suggested to take axles out and do the same test to check for bent axle(s) i had to leave so i left the car with them an picked it up later..but this test also had no result
so we're back to the tailshaft again..we talked about how far the gearbox yoke is in the extension housing on mine it has about 15 mm showing of the machined surface,they thought it should be more than that 25-30mm? so the yoke doesnt bottom out on the output shaft
we could have dropped the diff down a bit and took it up to 100 kays on the axles stands but we ran out of time..
tomorrow im going to take the tailshaft out and check the gearbox yoke for evidence of it bottoming out on the output shaft
the tailshaft has some runout(more than i'd like) but talking to the "tailshaft guy" he says thats not unusual..and its been balanced
i was all set to get him to make me a brand spanking new one$400-$500..but he says its a waste of time
the hunt continues.....oh..these guys spent the morning on it and didnt charge me ..i owe them a few beers they are "good blokes"
-checked tailshaft runout again..front less than 5 thou..middle 8 thou..rear 25 thou
-diff yoke 1-2 thou runout
-rear rims runout (roundness) 5-10 thou..nothing unusual
-checked diff alignment to body(with borrowed tool from near by panel beaters shop)..spot on
-took car off the hoist and jacked up the rear on axle stands and took it up to 100 kays@3000 rpm to visually watch tailshaft and wheels ..nothing unusual that we could see apart from an out of round tyre but that was there before with old diff an no vibration
-took wheels off ..up to 100 kays again..vibration still there
-one of the guys suggested to take axles out and do the same test to check for bent axle(s) i had to leave so i left the car with them an picked it up later..but this test also had no result
so we're back to the tailshaft again..we talked about how far the gearbox yoke is in the extension housing on mine it has about 15 mm showing of the machined surface,they thought it should be more than that 25-30mm? so the yoke doesnt bottom out on the output shaft
we could have dropped the diff down a bit and took it up to 100 kays on the axles stands but we ran out of time..
tomorrow im going to take the tailshaft out and check the gearbox yoke for evidence of it bottoming out on the output shaft
the tailshaft has some runout(more than i'd like) but talking to the "tailshaft guy" he says thats not unusual..and its been balanced
i was all set to get him to make me a brand spanking new one$400-$500..but he says its a waste of time
the hunt continues.....oh..these guys spent the morning on it and didnt charge me ..i owe them a few beers they are "good blokes"
Edited by S.S., 02 November 2012 - 06:11 PM.
#54
View GaragePosted 02 November 2012 - 09:39 PM
Normally work on 20mm for the slip yoke but it won't move that much in a lowered Torana and if you observed the vibration with it on stands it seems quite unlikely (the only trick being you need to know where the output shaft itself ends, sometimes they stick out a bit). If it was the extension housing bush or bent output shaft or driveshaft there would likely be visible movement which you didn't see. Given that the diff was the factor that changed it still points back to either the uni angles or maybe the diff itself (pinion bearing, bent pinion?)
I notice on the previous page you said the Falcon driveshaft uses the same unis as Commodore - I had one that was close but not quite a proper fit, the one with the retaining clips that go on the outside of the uni cup isn't the same as the Commodore style.
I notice on the previous page you said the Falcon driveshaft uses the same unis as Commodore - I had one that was close but not quite a proper fit, the one with the retaining clips that go on the outside of the uni cup isn't the same as the Commodore style.
#55
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Posted 03 November 2012 - 01:08 PM
hi mate..taking the tailshaft out to check wether its basically too long is just another thing to eliminate on the list..bent pinion i doubt it would have thought putting a dial indicator on the diff yoke would hve showed that?Normally work on 20mm for the slip yoke but it won't move that much in a lowered Torana and if you observed the vibration with it on stands it seems quite unlikely (the only trick being you need to know where the output shaft itself ends, sometimes they stick out a bit). If it was the extension housing bush or bent output shaft or driveshaft there would likely be visible movement which you didn't see. Given that the diff was the factor that changed it still points back to either the uni angles or maybe the diff itself (pinion bearing, bent pinion?)
I notice on the previous page you said the Falcon driveshaft uses the same unis as Commodore - I had one that was close but not quite a proper fit, the one with the retaining clips that go on the outside of the uni cup isn't the same as the Commodore style.
the diff had all new bearings put through it altho the centre itself wasnt rebuilt just shimmed up..usually the centres make a "rumble or whine"
the tailshaft to pinion angle could be a problem(without an angle finder)looking at it on the hoist the tailshaft looks very straight on the the pinion?
thanks for your comments
#56
Posted 03 November 2012 - 08:22 PM
If you're not 100% certain on the uni angles then that would definitely be the place to start, very likely that the diff conversion may have altered it so would make sense
#57
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Posted 04 November 2012 - 06:56 PM
so it wasnt that the tailshaft was too long..i undid tailshaft at the diff yoke and it slips forward a further 20mm so one more thing crossed off the list
will try an get a anglefinder/protracter this week to check angles
will try an get a anglefinder/protracter this week to check angles
#59
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Posted 26 November 2012 - 05:43 PM
i would like to say to all those people doing a borg warner diff conversion(commodore) and one peice tailshaft in their torrie with a driveline vibration to pay perticular attention to that diff yoke coupling
with the advise of a mechanic friend of not doing the coupling bolts up tight as a test..to have them "just" tight to allow the coupling to centre its self albiet a few thou did the job
on about a 60 kay drive at first the vibration was much better and it improved to be gone completely..on commodores they have a centre bearing which probably corrects alot of tailshaft problems
im going to white mark the diff yoke an coupling so that if i have to take the tailshaft out at any stage i can put it back on the same way
so..beware of that damn commo tailshaft coupling in 1 piece tailshafts on torries..
cheers
with the advise of a mechanic friend of not doing the coupling bolts up tight as a test..to have them "just" tight to allow the coupling to centre its self albiet a few thou did the job
on about a 60 kay drive at first the vibration was much better and it improved to be gone completely..on commodores they have a centre bearing which probably corrects alot of tailshaft problems
im going to white mark the diff yoke an coupling so that if i have to take the tailshaft out at any stage i can put it back on the same way
so..beware of that damn commo tailshaft coupling in 1 piece tailshafts on torries..
cheers
Edited by S.S., 26 November 2012 - 05:53 PM.
#60
Posted 26 November 2012 - 08:45 PM
Sounds like you have a damaged or mismatched flange, the centring spigot which locates these is about the only driveshaft coupling which doesn't require extra work to get right!
#62
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Posted 26 November 2012 - 09:35 PM
all i can say is it worked for me..and when they make/balance a tailshaft with the commodore spigot coupling where do they grip it and at what speed do they balance the shaft 2000 rpm..since my vibration only started at 3000 rpm could the tailshaft guys miss that?Sounds like you have a damaged or mismatched flange, the centring spigot which locates these is about the only driveshaft coupling which doesn't require extra work to get right!
#63
Posted 27 November 2012 - 05:41 AM
Not 100% sure what sort of adapters they use at that end but there's a good chance it won't match the way its coupled in the car. The extent of the balancing varies too, sometimes near enough is good enough and factory tolerances were never great - I normally tell them its for a race car or some such so they will assume it does high revs and get it finely balanced...!
All's well that ends well anyway, just keep an eye on it and make sure it doesn't get off centre again
All's well that ends well anyway, just keep an eye on it and make sure it doesn't get off centre again
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