Second Hand Pot Joint Outers
Turbo Mini Forums

Two quick questions relating to inner CV joints:

With pot joints is it the outer* casing that wears, the inner bearings or both?

Are the outer casings inter changeable? or do they become matched to the inners as they wear?

Basically I want to modify a couple (don't ask) and I'd rather not buy a new pair for £60 if I can get a second hand pair for free (I'm pretty sure if I look hard enough I've got a second hand pair in the workshop)

EDIT: * by outers I mean the outer housing of the inner CV joints

Edited by Rob H on 13th Apr, 2008.

Hay do you want to modify a couple? lol

I remember mr fenton posting that there are two sizes of pot joint, if he says so then it must be true, but i've always mixed the parts willy nilly.

There are indeed two sizes. Caused me a weekend of messing around. Fuck BL!

Cheers guys

speed sensor?

Yep speed sensor,

I was originally thinking about fitting a magnet to the rear hub like most off the shelf after market speedos, but the problem with that is the length of time between the pulses means that to get a good resolution and rate of update you need to measure the time between the pulses and calculate your speed from that, were as if you increase the rate of puses to about 8 per revolution you can simple count the number of pulses over a set duration of time (say 0.5 secs) and use that to calculate your speed, which makes the electronics a lot simpler and cheaper.

so Rob , what does this ahve to do with the wear rate of the CV's.

, i'd say a bit of both, balls and outer housing, but probably outer case slightly more than the balls,


carl

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as the balls are harder?

regarding the resolution, when I had an astra gte with the digital dash i used to reallu notice the resolution at low speed (stop start traffic) you could be doing 5 mph and stop and it would still say 5 for a cuople of secs before going to 0 although thats as much to dowith thee sample rate i guess...

howa about rigging something up on the primary gear bit/speedo output. this will be turning ant least 2.9x faster so give better resolution.

in that case the outer housing is through hardened is it not,so will be a pig to machine,id be tempted to make up a disk and weld it on to it, if theres room,


carl

Edited by fastcarl on 13th Apr, 2008.

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Rob,

Have you considered an optical sensor and just paint a white line on the pot joint?

I have a circuit for an optical sensor somewhere for my digital dash project.

Not good for a road car as it would get mucky quick, but track would be OK.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

hmmm,

Paul do you recon the circuit could be used to measre turbine speed?

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Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

shame, tats just about the only gauge i havent got lol

Easier to weld a toothed ring to the pot joint.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I've also thought of doing this, the problem I thought of is the amount of play there is in the pot joint, most sensors require a gap of .5mm and max of 1.5mm, I think my pot joints move more than 1mm.

why not pickup of the teeth on your crown wheel?

Team www.sheepspeed.com Racing

I dont think pot joints should move more than that with reasonable bushes in the side covers?

Rob,

Did you or anyone ever try to machine the pot joint?

I'm thinking of making up a pair of adaptors for my HS couplings from some old pot joints.

It may be a bit tricky if the outer case is hardened.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I didn't, I was going to get Roger to do the machining but he's dropped off this planet, in the end I went for the easier but more expensive solution of buying an SPA Tacho with a built in speedo and a few other trick bits.

Well, I just did a hardness test on a pot joint outer and it is as hard as hell.

I'll give that idea a miss for now.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I used to run off the pot joint, but the sensor/display I was using couldnt cope with the amount of pulses, anything over 30 and it just stopped.

It was only a bike speedo type thing though.

you can turn the pot joints if you have a decent machine with carbide tips,and coolant,iv'e parted one off once, tough but doable, i dont know about drilling it though, suppose carbide drills will do it ok,


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Seems timely this has come up as I could do with some sort of tone ring arrangement for the driveshafts (I have HS) to run the traction control on my ECU. I have launch control which works surprisingly well which picks up off the studs on the n/s/r hub but wired the car a long time ago for this with switches for the wet and dry settings (although more of a gimmic I suspect) as it is not really needed unless on AO32RS or extremely wet!

It was this wiring which being trimmed at the ends was causing the 5volt ECU output to feed back into the signal grounds (in turn connected to earth) and turn the ECU off! Obviously telling me it is time to connect them up!!!

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

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