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Stub axle wobble?


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#1 kroegarn

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Posted 03 January 2016 - 11:02 AM

I´m doing a rear end overhaul. Had a bad clonking noise which came from the rear diff, had the OBX diff overhauled and also tightened up the backlash a bit.

 

Second part up was the really bad vibration that showed up at speeds above 100 mph. Used a indicator dial at the adaptor plate for the 280 ZX Turbo drive axle, and it showed a difference of 1 mm. It was even possible to see the wobble with your own eyes. Removed the strut and using the indicator dial on the stub itself it wobbled a 1/10 of a millimeter on the left side, the right side was a lot better but not perfect. 

 

Is this something that is common? Will it happen again using the stock stub axles when trying out the surface grip with the 512 whp??  

Attached Files


/Mike

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Datsun 240Z -72 1JZ-GTE powerplant => 512 whp


#2 Miles

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Posted 03 January 2016 - 11:31 AM

Could just be that the bearings need to be replaced.

 

Also, check the runout on the wheel mounting flange. The flange is soft and can be bent hitting a curb. A bent mounting flange would cause the wheel to wobble.

 

Of course, check all of the rotating assemblies such as the drive shaft, half-shafts etc.

Attached Files


Edited by Miles, 03 January 2016 - 02:30 PM.

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#3 Miles

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Posted 03 January 2016 - 01:50 PM

You may want to consider these stub axles:

 

http://www.chequered...net/Datsun.html


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#4 RebekahsZ

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Posted 03 January 2016 - 06:35 PM

I found a bent stub axle when I did a rear disc brake conversion.

1972 240z, purchased in 1991 for $900. Bone stock LS2/T56/DBW from 2006 GTO, swap completed in 2011. 400rwhp/435 rwtq. 2400# minus driver. JCI swap, Mantic ER2 clutch kit, JTR headers, single exhaust, Borla muffler, MGW shifter, M2 Differentials shortened Z31 CV axles, Z31 CLSD R200, Chequered Flag Racing billet stubs and companion flanges. MSD 2-step, Hurst roll control, both operated from switches on clutch pedal. 9" Hoosier drag slicks on Weld Draglites, 245/45/16 Hoosier A6/R6 on 16X8+10 Rota RBR. 225/250 sectioned coilovers, Koni 8610-1437RACE shocks, DP and EMI camber plates, MM shortened rear control arms, TTT front control arms, poly and aluminum bushings. Top speeds: Ohio Mile 174mph, C/GMS class record holder, best 1/8 mile 6.96 at 100mph, best 1/4-mile 11.0 at 126mph, best 60' 1.43, best 1/2-mile 148mph at GA 1/2-mile. Home Track-Jake's Dragway, Moulton, AL. SCCA autocross club - TVR, Huntsville, AL. Lets race!


#5 Miles

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Posted 03 January 2016 - 08:03 PM

I found a bent stub axle when I did a rear disc brake conversion.

 

Ditto RebkahsZ. Bent stub axles can cause problems.

 

I found that slightly bent stub axle flanges on my 240Z with 240SX rear calipers caused the pads to drag. Didn't catch it until I checked the run out on each stub axle flange. I had the flanges machined, but they were too far out.  I ended up buying the Chequered Flag stub axles and all has been well since. Remember the 240Z stub axles were designed to work with drum brakes so flange run out wasn't much of  a problem.


Edited by Miles, 03 January 2016 - 08:06 PM.

“Life is like arriving late for a movie, having to figure out what was going on without bothering everybody with a lot of questions, and then being unexpectedly called away before you find out how it ends.”    -Joseph Campbell


#6 heavy85

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Posted 03 January 2016 - 09:21 PM

I bent/cracked the flange going off-track sideways at ~80 mph. Went two more laps and later found cracked flange. In my case the symptom was squeak from the brake.

#7 Miles

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Posted 04 January 2016 - 12:30 PM

Pictures of typical stub axle failure points.

Attached Files


“Life is like arriving late for a movie, having to figure out what was going on without bothering everybody with a lot of questions, and then being unexpectedly called away before you find out how it ends.”    -Joseph Campbell


#8 NewZed

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Posted 04 January 2016 - 12:45 PM

Second part up was the really bad vibration that showed up at speeds above 100 mph. Used a indicator dial at the adaptor plate for the 280 ZX Turbo drive axle, and it showed a difference of 1 mm. It was even possible to see the wobble with your own eyes. Removed the strut and using the indicator dial on the stub itself it wobbled a 1/10 of a millimeter on the left side, the right side was a lot better but not perfect. 

 

Is this something that is common? Will it happen again using the stock stub axles when trying out the surface grip with the 512 whp??  

A few basics seem off here.  Looks like your dial indicator probe is sitting on the threads, and the shaft itself, alone, may not be what determines if the flanges run true.  When the axles and companion are bolted together things may be different.  Along with the bearing play.  Probably best to measure an assembled set.

 

100 mph doesn't really have anything to do with 512 whp.  You can get there with 150 probably.  Just saying, traction and torque cause different problems from high speed spinning.

 

Is the adaptor plate the same one that Miles shows in his link.  The Modern Motorsport 280ZXT adapter?

 

 

(Note to mods - I thought that I had posted on this earlier with a comment about quality.  If I did, and offended, please let me know.  I thought it was innocuous and relevant.  But maybe there's some sensitivity.  Or maybe I never hit Add Reply.  Not sure).



#9 kroegarn

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Posted 12 January 2016 - 01:08 PM

Thanks guys for all your input!

 

I had the stub axles over to a friend of mine where we could put them up in his lathe. The stubs themselves are actually pretty straight and fine BUT the adaptor plates seems to be the culprit. Not sure if I can find any machine shop that can balance them, otherwise I´ll have to source myself a set of new ones. 

 

Regarding where they are from I actually don´t know, but they look like this (one is modified for the speed sensor): 

Attached Files


/Mike

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Datsun 240Z -72 1JZ-GTE powerplant => 512 whp


#10 CHEQUERED FLAG JOE

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Posted 14 January 2016 - 05:54 AM

I have new 280ZXT adapters if you need a pair.

Joe

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http://www.modern-motorsports.com

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#11 kroegarn

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Posted 17 January 2016 - 05:43 AM

I have new 280ZXT adapters if you need a pair.

Joe

 

Great... but just realised that I have the 240Z stub axle and not the 27 spline 280z version :(. With the now weak Swedish Krona I´ll have to at least investigate a more local solution.   


/Mike

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Datsun 240Z -72 1JZ-GTE powerplant => 512 whp


#12 NewZed

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Posted 17 January 2016 - 08:58 AM

As I understand things, the 240Z and 280ZX use the same diameter and spline count.  People swap in 280ZX axles for 240Z, by modifying the dust shield. The 280Z is different.  So the 280ZXT adapter might work.



#13 kroegarn

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Posted 17 January 2016 - 09:53 AM

As I understand things, the 240Z and 280ZX use the same diameter and spline count.  People swap in 280ZX axles for 240Z, by modifying the dust shield. The 280Z is different.  So the 280ZXT adapter might work.

I was a bit unclear, but my stub axle only has 25 splines so buying the 27 spline adapter would also require the Chequered flag stub axle (or equivalent). 


/Mike

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Datsun 240Z -72 1JZ-GTE powerplant => 512 whp


#14 NewZed

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Posted 17 January 2016 - 10:14 AM

Sorry, I didn't get it.  My mistake.  Thought you meant 280ZXT flanges.  Good luck.

 

BUT.  You could get some plain old factory 280ZX axles, for the CV cars, turbo or 2+2, and swap those in.  Here's a write-up.

 

http://zhome.com/rnt.../HalfShaft.html



#15 240zdan

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Posted 28 January 2016 - 08:51 AM

Id be willing to place a bet that your bad vibration above 100mph is a drive shaft problem. Balance/run out will cause a DS to vibrate like mad at high speeds, minor runout in the adaptor plates or axles/wheels will not so much. I had a bad vibration and too found run out on one of my adaptor/stub axles. Fixed the problem vibration remained. It ended up being a DS that was out of balance, even though I it had made and balanced at a shop it still vibrated on the car for whatever reason. I hose clamped a large washer to the DS and moved it around until the vibration disappeared. You can also try rotating the DS on the pinion flange. Throw a indicator on the DS as well and see how much it runs out. I had .001" of DS runout on the car, and rotating it on the flange did not fix my vibration. The only thing that did was hose clamping a large washer to it, exact opposite end of where the shop installed a balance weight. A Lot of these shops cannot spin their shafts past 3000rpm, and this is when my vibration begins. With 4.11 gearing the problem only gets worse.

 

Now I am not saying this IS your problem, but Its something to look over with a fine tooth comb.


Edited by 240zdan, 28 January 2016 - 09:00 AM.

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#16 duragg

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Posted 16 February 2016 - 05:37 AM

I have new 280ZXT adapters if you need a pair.Joe


I may call for a consult today. I have 27spline stubs with stock u-joint halfshafts. I detect some bearing play and I get nasty vibration on hard corners. (275 Hoosiers). Time to open these back up, check runout and consider CVs etc.

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#17 kroegarn

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Posted 26 February 2016 - 06:25 AM

I ended up ordering the stub axles and companion flanges from Chequered flag!! Now it´s all about waitiiiiiing for them to arrive and get that Z back on the ground! :)


Edited by kroegarn, 26 February 2016 - 06:27 AM.

/Mike

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Datsun 240Z -72 1JZ-GTE powerplant => 512 whp


#18 Miles

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Posted 26 February 2016 - 10:43 AM

I ended up ordering the stub axles and companion flanges from Chequered flag!! Now it´s all about waitiiiiiing for them to arrive and get that Z back on the ground! :)

 

You may already know this, use a locknut from a 280ZX instead of the stock nut. The 280ZX is self locking. The stock nut has to be peened against the axle shaft which makes future disassembly difficult. 

 

Also, make sure that the bearings and grease seasl are perfectly seated before tightening the lock nut.


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#19 280kid

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Posted 02 January 2017 - 04:20 PM

I have new 280ZXT adapters if you need a pair.

Joe



#20 280kid

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Posted 02 January 2017 - 04:22 PM

Just to get this right, you have the last and right one for sale? Will it work for 81 turbo? And does it matter the side they go on.




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