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VIBRATIONS
http://www.ozdat.com.au/forum/viewtopic.php?t=27713		 Page 1 of 2
Author:  1800jfarts [ Mon Jan 09, 2012 1:23 am ]
Post subject:  VIBRATIONS
I have had the propshaft balanced and the gearbox extention bush replaced and i still have the blady vibration!! Now could the solid axle bushs be the cause or the differential pinoin bearing? The rear wheels are balaced as well If the cars is towed with no propshaft the car is is smooth . i am now totaly flawed as to what can be the cause. Surely a DATSUN MAN could solve the problem? :D
Author:  666DAT [ Sat Jan 14, 2012 1:00 pm ]
Post subject:  Re: VIBRATIONS
was the propshaft balanced properly? wouldnt be the first time ive had a bad balancing done. for instance i had a mob machine and rebalace a crankshaft for an l28 race motor i go it back looked great put it together and the crank was way out of balace i have never delt with them again and far as i know they are now closed for good. if the prop was balaced properly try unijoints. or bend axle
Author:  richardc [ Sun Jan 15, 2012 9:35 pm ]
Post subject:  Re: VIBRATIONS
I agree with 666DAT, and you seem to confirm it as there is no problem if the prop. shaft is removed. Have you had the prop shaft modified in length?

The most likely propellor shaft problems are; the propellor shaft is not balanced, or bent, the universal joint end fittings are not fitted squarely, or not in alignment. Check the uni joint fitting at both ends are mounted in the same plane, if not then there will be an inherent out of balance problem.
Author:  666DAT [ Mon Jan 16, 2012 7:16 am ]
Post subject:  Re: VIBRATIONS
also where the prop shaft ataches to the diff did you mark exactally where it originally lined up? i came unstuck once when i replaced a clutch and had to remove the wole box awat from the car dropped the prop shaft off at the diff and didnt line it back to where it originally was, made a ver bad noise and you could feel it getting wobbly, this may not be you poblem but just check because sometimes they wear a pattern into the metal plates which can be enough to put everything out of wack. but honestly im thinking your prop wasnt balanced properly.
Author:  unfamilia [ Thu Mar 01, 2012 8:42 pm ]
Post subject:  Re: VIBRATIONS
sounds like a bad uni joint- i just had my tailshaft shortened again balanced and new unis- wobble gone as previously was a little short and had too much play.

so bad uni and little short left a bad wobble between 80- 100 but ok rest of the time.
Author:  SR20Datsun [ Sun Mar 25, 2012 7:08 pm ]
Post subject:  Re: VIBRATIONS
I went to Calder raceway the other day, and down the front straight at around 180km/h I had a vibration from the back end which when traveling up to 200 it would stay pretty much the same (I was hoping it was just a harmonic). I have CV's in the back end, so I think it may be the tailshaft needs to be re-balanced. What do you all think? Any help would be appreciated as i wanna go faster than 180 without vibration!
Author:  sled510 [ Sun Mar 25, 2012 7:44 pm ]
Post subject:  Re: VIBRATIONS
Lets see if we can get a group buy on balancing! I got the same issue. :lol:

I know my half shaft unis are stuffed so i have started to replace them. Next will be tailshaft unis and balance.
Author:  SR20Datsun [ Sun Mar 25, 2012 7:51 pm ]
Post subject:  Re: VIBRATIONS
Do you have it at high speed or at the typical 80km/h?
Author:  sled510 [ Sun Mar 25, 2012 7:57 pm ]
Post subject:  Re: VIBRATIONS
high speed, unsure what but probally close to 6000-6500 in 5th with a 4.6. Could be afew causes though, flat spotted tyres from sitting or i probally didn't balance the rear wheels(not like i ever have previously balanced consumables).
Author:  SR20Datsun [ Sun Mar 25, 2012 8:02 pm ]
Post subject:  Re: VIBRATIONS
Keep me in the loop Waz after you get everything sorted
I've got my wheels/tyres balanced, and I'm fairly sure everything else should be alright. I'm kind of leaning towards the tailshaft being out of balance at the moment, but don't understand why it doesn't happen at lower speeds.
Author:  sled510 [ Sun Mar 25, 2012 8:12 pm ]
Post subject:  Re: VIBRATIONS
Will do!
Author:  Anth510 [ Sun Mar 25, 2012 9:10 pm ]
Post subject:  Re: VIBRATIONS
waz if you're still using stock half shafts at that ride height then I'd say they'd be the culprit, mine used to vibrate at anything over 80kmh before I switched to CVs
Author:  sled510 [ Sun Mar 25, 2012 10:02 pm ]
Post subject:  Re: VIBRATIONS
Your car is lower than mine :lol: . Its fine at speeds probally upto 160 and then gets the death rattles then.
Author:  1800jfarts [ Sat Jul 29, 2017 3:19 am ]
Post subject:  Re: VIBRATIONS
Hi me again with the vibration!!
I am going to put the car on trestles, remove the rear wheels and brake drums.
Then I am going to remove one drive shaft[half shaft that the wheel bolts onto ] and run the car.
If it still vibrates then remove the other driveshaft [the shaft/pipe from the gearbox we call a prop shaft]
If it still vibrates then the problem must be the pinion bearing.
The part between the gearbox and the differential [prop shaft] has been checked three times.
QUESTION: Can the half shaft be removed without taking off the brakes backing plate which then means i have to disconnect the brake pipes? Thanks for the future advice :)
Author:  SR20Datsun [ Mon Jul 31, 2017 12:10 pm ]
Post subject:  Re: VIBRATIONS
Have you checked the runout on the tailshaft, drive shafts and tyres? This is a quick way of checking without removing anything.
My tyres had flat spots for sitting for so long. The only way I could find this out was to run a dial gauge over them. I had them balanced, but they didn't find any problems which was interesting.
My tail shaft was within specification (0.5mm max) and so where my CV's.
I did change the pinion angle, but not sure if that made any difference as the angle wasn't too bad to start with.
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