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620Z

Bent my Drive Shaft again

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They are heavy ind type but there is more the auto type which they dont have the tech data avail well from this site anyways.

But the kgf/m is actually deceptive you have to x by 9.81 to get N/m so what ever you se in kgf/m times by 10 and your on the money, yes those particular items were only rated to about 6-8k, but ive read a catalogue recently where the were rated to 25k revs, and something stupid like 200kgf/m torque and they were about 288$ + tax!!! cheap angular power transmission there i tell ya,( remem x by 10 for Nm.)

 

but even saying using a CV you will still have the same problem if there is slight off centre drive, ie output shaft bearings in trans and same on the diff, if under load the shaft ofr bearings let the shaft deflect slightly then you hammer the revs it will cause a CV to fail pre maturely also. And this is also the reason that i think this is why the 1310 unis went also. remember the engine torque is multiplied by your 1st gear ratio and then by your diff ratio but the DS only sees 1st gearXengine torque to the limit of traction anyhows!!!

 

Informed yes, homework not really just thought id post you a link to this type of power transmission items, i have studdied and done plenty of projects requiring these sorts of items along with shafts and bearing loads etc.

 

nato

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Yeah interesting.

The jury is still out as to whether my 1310 Uni's are failing. But I hear some drag guys with 1800bhp are running these 1350 uni's against advise but still holding. Bit of over kill for me but at least it's another problem area to eliminate and look elsewhere should I still have a vibration. So I will see when it all goes in.

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OK here is an update on the whole Drive Shaft problem.

I got a new big beefer made up 2.3mm shaft wall, 1350 uni's same size as the V8 Supercars use and new flange for the diff.

I drove my car for the first time in months to get it installed and realised that most or 95% of the vibration was gone. Hmmm why or how could this be. After putting it on the hoist at Daniel Moore's place we or he deduced the most likly cause of the problem. The twin exhaust that runs inside the tunnel either side of the D/S (1.75" away) was heating the Shaft that much after prolonged use it softened the metal and bent the Shaft a bee's dick or more under max load. Then when it cools down and settles for a period of time (Week?) it has returned or almost returned to it's original configuration. That would explain why it was almost gone and why on the last 2 days of the Tassie trip when it copped a caining over a period of 1-2 hours of constant use that the vibration came on so bad.

So do I put the new one in of leave it? $900- sitting there weighing 3.5kg heavier! Ah stuff it. We threw it in since I figured the old one would still have to be out slightly. Anyway the problem is solved and I will be wrapping the exhaust in heat shield to try and keep the temperature down on the shaft before the Island trip. I will get the other one checked out but it seems like the most likely scenario.

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i got to revisit my tail shaft and trany mount. too many vibrations at higher speeds. at low rpm i can feel it through the body fairly solid tranny mount. but when higher speeds the tailshaft takes over. anything over 120 its pretty bad.

 

i wonder if your old one will suit my car LOL. even if its slightly bent i think its lot better than my current one.

 

good that you got it all sorted out.

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Good to hear after spending the dollars you sorted the problem as I know there was still that little bit of uncertainty before you got it in. Should be heaps of fun for the P.I cruise!

 

Sulio

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well had few days of work and i thought i put some of those hours into the z.

 

tailshaft was removed and was sent for rebalancing. (apperently was bad  >:()

after reweld apperently didnt need balancing.

 

while all that stuff was appart i noticed my diff mount was cactus so new one ordered from nissan.

also re visited my almost solid trany mount with new insulator and redone the metal work.

 

all fitted back and the car is transformed. so quiet and smooth. $300 after was definetly worth it.

 

so Craig u inspired me to revisit some issues and definetly was a big reward. now i got a vibration less 2+2 too ;D

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Well done RBZ. Glad to here it is all fixed. Obviously the out of balance shaft vebrated that much that it would have effected or cracked the mount. I drove my car for the first time at high speed on the weekend. Feels really smooth at 6,500 or more rpm now. I still have a minor vibration at lower speed but I reckon it is to do with the newish rear mount being to tightly put together. I am going to buy some new bush's and replace the noelthane ones for rubber ones. I reckon that should do the trick. This is only a minor tweak for a fussy bastard since it is pretty good these days.  :)

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i think the mount was questionable initialy looked bit grubby but when cleaned up it had small seperation of the rubber from one side to the other. though after driving it with dodgy tailshaft the whole thing was just loose.

 

the new one from nissan a post 75 mount is bit different than the one i had. the rubber area in front is almost doubled. apperently this was the heavy duty version for the r200 model diff. also bit more pricey the pre 75 mount was $95 Trade while the post 75 was $120 trade. Rare Spares for the heavy duty wanted $148.

as i needed it urgently i got one from Nissan on Overnight Service.

 

well now the car feel so smooth that it actualy feels slow  >:( may have to bump the boost up slightly more to make it more fun.  ;D

 

yeah the nolathane stuff is bit brutal for everyday car. bit too stiff. hence i redid the trany mount for softer rubber type. lot better and more comfortable to drive. even the missus noticed the big difference.

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Sounds like a Job well done. I actually thought the same about my car being slow the other day. Ha.  Mind you it shot up the rev's in no time so interesting that we  had the same experience. I guess I have to get it back on the track now to make sure the times are the same. In reality we would have lost power because of being out of balance. So maybe we picked up a bit.  ;)

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