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While dropping my rear suspension & Diff...


Mikelly

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...Last night I figured I'd put my dial on the stub axle conversion flange for the CV joints and spun the axle in the carrier before pull the stub axles out. I spun it a couple of times and it looks like I'm getting 30 thousandths run out... I need to double check it, but if it is that bad (Obviously something shifted while I was welding..) what are my options? Can I have the assembly as it is welded up now balanced??? Thank god I've only done one of these so far...

 

Mike icon_confused.gif

 

[ May 04, 2001: Message edited by: Mikelly ]

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I realize trial and error balancing is a PITA, but an old drive shaft balancing trick I went with one time was to take two hose clamps large enough to fit around the drive shaft, and install them next to each other, onto the drive shaft so that the wormgear parts were on opposite sides of the shaft (they counter balance each other at this point and do not effect the balance). Then through trial and error, I would incrementally move the gear ends around the shaft toward each other and determine if it helped or hurt the situation, then re-adjust again, and again, until the vibration did disappear. In your case, putting the clamps around the CV joint may work. Or you could just take a chance and put longer bolts on the short side of your run-out (i.e bolts with more mass), and even add washers as counter weights to that side on the longer nuts if you need even more mass.

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Guest scca

wouldnt .030 runout shake like hell?

i know on brakes i shoot for .004-.006 runout max.. i like to see .003 or less but a tiny more is ok.. at 6 you will feel it. so i wonder if 30 will shake or not-- it is on the inside but still "boltd" to the wheel in a sense..

 

??????

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Mike,

That is what I was thinking as well. .003 or less is what I would shoot for as acceptable for my 200mph project car. I'm hoping that when I go to re-assemble everything after the powder coating, I'll find that I was wrong... But do I go ahead and risk it and weld the other unit up and then just have them both checked, or let someone else do the complete assembly and welding.. I assume these units were zero'd in when they were machined but i need to double check that as well. What I don't want to do is have to CV adapters that won't be able to be used...

 

Mike icon_rolleyes.gif

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I'm curious as to what the torque ratio will be with an off-axis torque applied to the axle. I realize this may be splitting hairs at only .030", but we're at the limits on strength pretty much here anyway I would think for 200mph? Also, please remind me: run-out is off-axis missalignment? What is the term used for a wobble in which the rotating plane is not perpendicular to the axis? Or have I got the two mixed up. icon_confused.gif

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Actually, Mike would have to specify, since runout could be measured parallel to the centerline of the stub axle, or perpendicular. Rotor runout is parallel to the stub axle centerline. Is that what you meant, Mike (Kelly)? If so, how about having a machinist chuck the adapter/companion flange weldment to a lather and true the surface? Fixturing it so that it turned true to the stub axle splines might be difficult though.

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Mike,

 

how high a speed did you have the car up to before taking it apart and did you sense any vibration at all? I understand the concerns considering the speeds you expect to hit, but I would hate to see you chasing a problem that might not be there.

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Scottie,

The unit was never on the car while it was running. I'm currently still in the middle of re-doing the car from last winter, and I'm just dropping everythingout from under it to have it powder coated. When I dropped the rear suspension, I stick my dial on the top outter cent of the (Picture the Top of a cirlce basically) unit and spun it and noticed that the run out was .030 off. I'll triple check it. The other issue though is those flages were tight fitting in there, and I expect that it woldn't be that far off based on how tight the box was for the flange...

 

You guy following this??

Mike

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Guest needwaymorespeed

so youre talking side to side runout

I think yopu could do what pete suggested and have it trued up in a lathe-how does it look fore and aft thats what is realy important

stick dial indicator an inchdown on adapter and indicate the face of it

later

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Nope, top to bottom run out...I mounted the dial on the top of the round adapter flange... It rode on the circle as it spun... this showed a run-out of .030! To better visualize it, it would be like looking at a wheel on a bicycle and seeing it jump up at the high spot...

 

Mike

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