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Syncroincity Wed Jun 09, 2010 5:45 pm

My brain hurts... :lol:

Syncrozilla Wed Jun 09, 2010 8:59 pm

syncrodoka wrote: So once I figure out the needed axle length, I need to figure out plunge depth that the axle will go before hitting the flange and that determines where the circlip gets machined in? This is starting to turn into a little project for sure. :)
Exactly. On all the sets I've put together we put a limiting circlip on the outer joint but not the inner. Gravity wants to keep the axel sliding towards the wheel side. I did not want the axel to be able to contact the stub axel. I don't really care if it contacts the output flange on occasion. Unless you want to run the factory seal, then you would need to do this. Since spending all this time figuring this out it occurs to me now that since the vanagon does not really have all that much travel compared to some off road stuff you could also possibly add some circlip grooves that would just trap the cv's in a totally fixed spot. At least the outer one anyway. Maybe that would be the KISS solution.

syncrodoka Wed Jun 09, 2010 11:29 pm

Quote: Maybe that would be the KISS solution.
That's my style- keep it simple.
It would give the axle less chance of beat up the circlip from it sliding back and forth too. Thanks for the tips.

SyncroGhia Thu Jun 10, 2010 12:59 am

Syncrozilla wrote: Since spending all this time figuring this out it occurs to me now that since the vanagon does not really have all that much travel compared to some off road stuff you could also possibly add some circlip grooves that would just trap the cv's in a totally fixed spot. At least the outer one anyway. Maybe that would be the KISS solution.

This is how the front is setup with the outer being held firm and the inner allowed to slide more freely.

Sounds like a plan to me.

MG

Syncroincity Thu Jun 10, 2010 6:27 pm

OK, KISSing it, how about just dabbing a couple or 3 of tack-welds into the splines at the point where you want the plunge to stop instead of machining for another snap-ring? Not like it's load-bearing or anything, and could be filed flat where it meets the CV star. I say this because I have easier access to my welder than a machinist. :wink:

syncrodoka Thu Jun 10, 2010 6:46 pm

I would be worried about the welding heat affecting the heat treatment that alllows the axle's torsional abilities.

Syncrozilla Thu Jun 10, 2010 10:04 pm

I'm sorry but welding on the axel is a HACKER move! Do you also have wires twisted together with a little electrical tape around them in you electrical system? How about sheet rock screws? They also show the special skills of a vehicle owner.

Ever try to weld on spring steel?

syncrodoka Thu Jun 10, 2010 10:05 pm

Quote: Ever try to weld on spring steel?
I have looked it up and it didn't sound like a good idea.

derekdrew Fri Jun 11, 2010 7:26 am

One benefit of the circlip at the outer of the axle seems like it is just for space. But where are talking about the axle side of the CV joint where the 930s are (front inner or rear inner and rear outer), then one could use fatter things, like a hose clamp or cv joint clamp or permanent clamp and to make it stay, maybe grind the ridges of the splines on the axle down at that point so the axle would be slightly narrower there, which would make it very hard for the clamp from moving along the axle. In this way, one might be able to avoid going to the machine shop with the axles except for the front outer position? Then, to top it off, maybe try red loctite on the splines in between the cv joint star and the axle for whatever that is worth. I measured very carefully the amount of plunge needed for a front stock suspension where the suspension drops down 1" further than in the stock setup, and even with the extra 1" drop, the plunge requirement up front is basically near zero. So, theoretically, you don't need the axle to move inside *either* joint, and all the movement would do is introduce wear (of an amount that some have said could be material to us). Not only that, but even the use of 930s seems to be quite unneccessary (in the front) because the stock vw oem 108mm joint has more than enough plunge in it for the job. I don't know whether the use of front A arm ball joint spacers would introduce a plunge requirement, or whether a Burley A arm would do so. I'd love for somebody to measure those cases. But it is hard to measure without precision measuring equipment because the range of plunge is so small. At the back outer position, I also favor the idea of a bagel (maybe plastic or hardish rubber, but otherwise like duncan doughnuts or a bagel) which is HOLLOW and cut in half through the middle and this being slid onto the axle inboard of the CV joint and affixed to a specific place on the joint. The idea here is that the outward force of the axle load then is distributed away from the star center and to the fixed outside edge of the CV joint, just under the rubber boot. The primary purpose of this is to encourage the CV joint to run with the star centered in the middle of the cv joint rather than over to the outside, which might otherwise happen when the weight of the axle is pushing the star outward. Long-term or frequent high power out-of-center CV joint operation has been raised as something that might not be optimal practice for 930s, and the hollow cut bagel device, for lack of better terminology, would put that concern to bed. The reason for the bagel being hollow is to make sure it does not contact the cage. Now that you have the idea of the bagel, the concept could just as easily be rendered with a metal spring about 25mm on one end and 103?mm on the other end, maybe 2? inches long, and affixed to the axle. I took out www.syncromadness.com but there is nothing new there you have not seen already, and all that stuff is from the early 1990s when I wondered about my sanity and did not have you pals around to make me feel like I was behaving as a normal person might. I am waiting for Seth to say that Loctite on CV joint splines is hacker stupid, since I really don't know.

Syncroincity Fri Jun 11, 2010 5:11 pm

Syncrozilla wrote: I'm sorry but welding on the axel is a HACKER move! Do you also have wires twisted together with a little electrical tape around them in you electrical system? How about sheet rock screws? They also show the special skills of a vehicle owner.

Ever try to weld on spring steel?

You forgot JB Weld. :shock: Just a suggestion, man, we're spitballing here. No need to come over all Vortex, lol... Good point about the spring steel tho, I had not really considered the metallurgy...

Derek, I dig the donut concept, particularly the load-alleviation on the CV star, it won't do to have the guts of the CV pooching out because of the weight of the axle pushing on it.

Something along the lines of these... cut into halves.


SyncroGhia Sun Jun 13, 2010 11:56 am

Just a bit of info on front inners..

I'm running 50mm longer front shocker pins, Burleys top arm spacers and Porsche 944 CV joints for inners and Syncro 16 outers and on full drop (the arm rests on the spring rather than the shocker topping out), the inner CV joint is very close to going into bind. It doesn't go into bind but if I pull down hard so the top arm pushes the spring out of shape a bit, it does.

I'm looking to replace the front inners with Syncro 16 rears when I replace the driveshafts. So far they're doing ok.

MG

syncrodoka Wed Jun 16, 2010 10:24 pm

Does anybody see any reason to not polish the 930 CVs before I install them?
http://www.dune-buggy.com/techtips/cv_joint_polishing.htm
I also found a good idea of determining the axle length then getting a dowel of the same length and cycling the suspension up and down a few times to double check length
http://www.shoptalkforums.com/viewtopic.php?f=28&t=123409&start=15
I am working 60 hr. weeks right now and won't be able to actually take apart the truck and get some hard numbers until next weekend.

SYNCROZILLA- It looks like I will be looking to have the front axles machined. I am chasing down the parts and a front locker right now. :twisted:
If anybody else wants to get some machined for future use, it would be a good time to get it done. Sometime next month when syncrozilla has time.

Syncroincity Thu Jun 17, 2010 1:55 am

Polishing will supposedly extend the wear life of the CV... it's one step in the "race prep" many shops and vendors offer, along with radiusing any sharp edges and stress points. Refer to my photos on page 1, showing one out of the set I got used from an off-road buggy... polished & race prep, with chro-moly cages & hardened stars. (the outside is polished strictly for looks on a car where the suspension is exposed) I also picked up a set of 0.002" undersized balls that EMPI sells for the 930 CVs, which I think are already in these CVs after playing with them for a while. Not sloppy loose, but the cage definitely moves around easier.

syncrodoka Thu Jun 17, 2010 5:37 am

yes, I know that this is what race shops do to improve the CVs(race prep). Is there and down side to doing this to the CVs? Will I be sacrificing service life for better action or is it now a better CV joint that has been relieved similar to porting/polishing a head?

dredward Thu Jun 17, 2010 1:00 pm

I am going to begine rebuildinding/exchangeing parts from my van, Mainly fr sub frame, suspension, brakes, new axles, lines etc...... From what i am understanding do i have to replace my rear axles with longer ones to use the 16in arms? I will run stocker cv's for the time being. I am not doing too much hard off roading so i am not concerned with 930 cv's. I understand that the added hight of the 16 arms, springs, and shocks will max out the cv's under extreme conditions but for the time being can i run my axles to get me by while i save some $ ????

syncrodoka Thu Jun 17, 2010 3:17 pm

Just the burley trailing arms with no lift or OME shocks and mostly street driven for now? You should be fine. The 930 CVs are to get more articulation when off road but you will never have that issue on the street. If I am wrong you can come over and tell me so :wink:

dredward Thu Jun 17, 2010 5:11 pm

syncrodoka wrote: Just the burley trailing arms with no lift or OME shocks and mostly street driven for now? You should be fine. The 930 CVs are to get more articulation when off road but you will never have that issue on the street. If I am wrong you can come over and tell me so :wink:
Thanks Mario. When i have the underside of the van a bit freshened up i'll likely do some off roading but nothing too major.

syncrodoka Sun Jun 27, 2010 3:18 pm

It looks like I got the wrong tranny drive flanges. After pulling the entire rear end apart I went to reinstall everything and the flanges won't fit. :cry:
I will have to try again next weekend- Dang.

SyncroGhia Tue Jul 06, 2010 10:40 am

Important discovery :)

I found my aftermarket 108mm output flanges and have just put them next to factory Syncro 16 output flanges.

The photos speak for themselves.

























Sorry once again for the large images.

This would account for some of the difference in driveshaft length of the Syncro 16 having shorter shafts than Syncro 14s. Unfortunately, I don't have a Syncro 14/2WD output flange to hand to put against these but I do have a front diff in the garage at present so that might change soon.

From what I've measured, the Syncro flange is 6mm taller overall than the aftermarket flange. 1mm of that is a deeper lip that the CV joint sits into and the other 5mm is overall length so this should be taken into account when working out driveshaft length.

MG

SyncroGhia Tue Jul 06, 2010 11:08 am

ALIKA T3 wrote: The Audi CV joints and others 108mm should be 32mm thick.
Porsche ones are thicker,like said,40mm-ish,depending on the factory....

I don't know why the axle length would change mounting thicker CV joints like the 930's,the end clip will still be at the place.(If the stub axles and flanges respect the same depth dimensions as the Typ25)

Measure to be sure,but you should find the same length as an original axle.that's my theory.

So... from the new info...

Stock Syncro 16 driveshafts are 524mm long (according to my Spidan book on the shelf although I meaured mine at 525mm), the aftermarket flanges are 5mm shorter (don't know what the difference might be on the hub flange???) and the 930 CV joints are 8mm wider each...

524mm + 5mm (flange) - 16mm (2 x 930 CV joints) = 513mm.

If the hub flange is anything like the gearbox flange, add another 5mm on and you get 518mm...

The 20.25" axles work out at 514mm so that's very close and probably what I'd be going for.

MG



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