yoeddynz Posted May 3, 2013 Share Posted May 3, 2013 Not so sweet vibrations. loads of info out there on this. Almost too much and many different views. My driveshaft vibrates at low revs pulling a high gear- example.. Pulling away from corner in third gear. Once at about 2000 it stops. Rattles my gearbox bearings. It never used to do this prior to swapping the engine. Not a peep. Gearbox rear is now about 20mm lower then it used to be. I suspect that the box output shaft now points down more. Maybe too much? At speed I have a vibration that sets in around 65/70 kph and goes away at about 100. Not sure if the two are related. This one seems to be coming from the rear of the prop and is definitely the prop. Again it never used to do this. So I need to look at my angles. I can modify the top links so they could be adjustable although not sure about the certification/ legalitys of this? I always thought that the prop had to be set with a fair degree of angle at each end and should never be straight. But since doing some reading on the subject it appears that this is not the case. So....Who has experience with pinion angles and have had similar vibrations that they have cured by adjusting it- I would like to hear from you and will make you a cup of tea. Quote Link to comment Share on other sites More sharing options...
cletus Posted May 3, 2013 Share Posted May 3, 2013 angles should cancel each other out for no vibration, if your rear susp arm bushes are a bit squishy pointing the nose of the diff down a little bit can help, as it comes right under acceleration Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 3, 2013 Author Share Posted May 3, 2013 yeah when the car is on a hoist I can fairly easily move the front of axle up and down. It's had new bushes, slightly updated Viva GT items but still a little squishy. I will really need to check the angles. I found this good info on pin pointing vibrations.. http://www.iedls.com/asp/admin/getFile.asp?RID=9&TID=28&FN=PDF My upper arms are just simple U channels that have a bush in each end. I was thinking of making new ones out of two bits of box section, one sliding inside the other and then pinch them together with bolts. Or put a rose joint at one end. What's the go with certing these? Quote Link to comment Share on other sites More sharing options...
vivaspeed Posted May 3, 2013 Share Posted May 3, 2013 I've rose jointed the tops arms on mine. Chopped a rubber bush end off, welded in an end plate with a threaded boss in it. Male rose joint screws into it with a jam nut. No cert on mine though, but I guess you'd just x-ray welds like other welded suspension bits? Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 3, 2013 Author Share Posted May 3, 2013 Yeah- I'll be happy with my welds- especially compared to what some of the existing Friday afternoon welds look like on some parts of the car. I'll just do it after the cert. Will measure and check angles. Might not need to change arms. Did you end up adjusting your arms much Geoff? Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 3, 2013 Share Posted May 3, 2013 Looked at your ujs? if they are old/worn then changing the pinion angle can lead to vibrations as they are used to running at the old angle. Have had it happen more than once after lowering cars Quote Link to comment Share on other sites More sharing options...
vivaspeed Posted May 4, 2013 Share Posted May 4, 2013 Did you end up adjusting your arms much Geoff? TBH I don't know how much they are adjusted from stock length. It was also about 4 years ago... I just put them in, used an angle finder to get diff flange and gearbox angles, adjusted arm length to suit (as close as could be). Also shat a rear UJ about 18 months of use (intermittent club use) after setting up new engine/gbox combo on an old driveshaft. Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 4, 2013 Author Share Posted May 4, 2013 Yeah Andrew- I'll check them out. Went to work today to borrow the protractor but the workmate who owns it had taken it home. Geoff- I imagine with a rose joint you might get more road noise into cabin? This I don't want- I mean a stock Viva is about as close to a rolls as you can get and I don't want to lose that plushness... 1 Quote Link to comment Share on other sites More sharing options...
vivaspeed Posted May 4, 2013 Share Posted May 4, 2013 You rode in mine at trackday. As you'll recall it was quiet and smooth, no diff noises, and certainly nothing transferred into the cabin... those Vauxhall engineers certainly took all practicable steps to reduce noise, vibration and harshness But, yeah rose joints do transfer some noise but leave one end rubber and it should be right. Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 4, 2013 Author Share Posted May 4, 2013 OH yeah. Your viva was like driving in a posh hotel bar, with the quietness of a library, comfortable seats like a lazy boy. It truly was a relaxing place to be. Quote Link to comment Share on other sites More sharing options...
sheepers Posted May 4, 2013 Share Posted May 4, 2013 angles should cancel each other out for no vibration, if your rear susp arm bushes are a bit squishy pointing the nose of the diff down a little bit can help, as it comes right under acceleration is there a diagram like this for two piece shafts??? 1 Quote Link to comment Share on other sites More sharing options...
Truenotch Posted May 4, 2013 Share Posted May 4, 2013 I'd like to know that also. Is it OK for the first shaft to be relatively straight on a 2-piece setup? Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 5, 2013 Author Share Posted May 5, 2013 From Inland empire driveline... "Angle set up for two-piece shafts is similar to the one piece. All 3 working angles should add up to zero. The easiest way to do this is mounting the front shaft section so it has zero degrees through the joint at the transmission. The rear shaft may then be treated as if it were a single shaft. Sometimes this is not possible and all three angles must be juggled to arrive at zero. It is a good idea to allow for some up and down adjustment at the center support mount so the angles may be tuned as necessary once the car is driven. There is no hard and fast law governing shaft lengths. It is customary though, to divide the overall length 40% front and 60% rear. Our experience with motorhome manufacturers has taught us not to make either shaft, especially the front shaft, shorter than 18 inches. Available cross members, frame obstacles and u-joint angle cancellation will all play their part in dividing up the span. All of the questions about power and intended use apply to the two-piece set. Like the one piece they can be upgraded in capacity. Unlike the one piece their tube diameter can actually be reduced because of the shorter shaft sections. This size reduction can eliminate a lot of floor pan, tunnel and seat bottom modification and may make a two-piece more economical to use where it isn’t really required." Quote Link to comment Share on other sites More sharing options...
sentra Posted May 5, 2013 Share Posted May 5, 2013 so...your not supposed to just jam a two peice into the angles that give the best clearance? who would have thought Quote Link to comment Share on other sites More sharing options...
Truenotch Posted May 5, 2013 Share Posted May 5, 2013 Our experience with motorhome manufacturers has taught us not to make either shaft, especially the front shaft, shorter than 18 inches This is interesting. Can anyone justify why this might be? Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 5, 2013 Author Share Posted May 5, 2013 Maybe because being so short its hard to get an angle less than 3 degrees? Quote Link to comment Share on other sites More sharing options...
toyabusa Posted May 5, 2013 Share Posted May 5, 2013 Interesting they say 0 degrees is ok as I was taught that they need some angle so the rollers roll and are not loaded hard into the cups. I've been shown one that had been flogged out due to this, you could clearly see the rollers had left imprints in the cup. Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted May 5, 2013 Author Share Posted May 5, 2013 I always thought that too. But it seems not. I guess they do see some angle changes with axle movement and vehicle loading - unless its the front prop of a two setup or a single in an IRS rear end. Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 6, 2013 Share Posted May 6, 2013 i will take some pics markku of mone from the back to give you an idea 1 Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 6, 2013 Share Posted May 6, 2013 see if this helps Quote Link to comment Share on other sites More sharing options...
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