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  View original topic: Porsche 930 CV conversion axle length? Page: Previous  1, 2, 3, ... 16, 17, 18  Next
onwardtothestars Fri Jun 04, 2010 11:10 pm

the answer is out there, people just want to keep it secret to profit off it.

Syncroincity Fri Jun 04, 2010 11:21 pm

syncrodoka wrote: I don't know about your tranny flanges/stub axles, but I was looking at mine and they are taller than stock and I will definately have to install them to determine the axle length. The Sway-A-Way instructions are the way that I am going to get a axle length, but they say to check both sides as well. Unfortunately it means ripping out the tranny drive flange seals and installing new ones. Pulling everything out to install the hardware temporarily then switching back to stock then reinstalling everything once the axles arrive sounds like a waste of at least 4 seals. Having the truck non-operational for a time is no fun either. :cry:

I have the same flange set from Avery's that you do.
Pick up some of these... about $13 for a set, and they're re-useable



syncrodoka Fri Jun 04, 2010 11:30 pm

r39o said
Quote: As an aside, do you really need the 25 degree swing of the 930 CV?
You haven't seen me drive :twisted:
In the last year and a half I have replaced 6 cv boots and 2 CVs, I am done with the stock stuff. It is amazing how many empty brand new CV axle assembly boxes you see around SDM on the last day. I have more HP and drive the truck for what it was intended, so yes I do need the 930 CVs.

syncrodoka Fri Jun 04, 2010 11:32 pm

Interesting, I will have to track down some of those. Thanks

SyncroGhia Sat Jun 05, 2010 2:46 am

I'm looking at running a lengthened pair of trailing arms (3-4 inches or so) and would be interested in comparrisons of flange to flange dimensions for a stock Syncro 14 and then a Syncro 16.

MG

Syncrozilla Sun Jun 06, 2010 9:19 am

syncrodoka wrote: Interesting, I will have to track down some of those. Thanks


You don't need those. If your running the empi or sway away style axels they will just destroy those cups. Just put the flanges on clean and dry and fill the area inside the flange where the snap ring is with ultra grey RTV.

Also don't forget that something needs to be done to keep the axel from contacting the outer flange or it will wear a groove in it over time and the flange will break off the stub axel. On the sets that I have put together I have put a snapring groove inside the outer cv to prevent the axel from sliding all the way into the outer flange. Another idea I had was a teflon "button" on the out end of the axel. The button would screw into a threaded hole on the end of the axel. This is only an idea as I have not looked for someone who can machine up some teflon buttons.

The only trick to the fronts is finding someone with a good enough lathe to machine the axels to accept the outer cv joint. This is tough as the splined spring steel axels like to break tooling on lathes. I was told to not come back to a few machine shops before I found one who could do this work for me.

syncrodoka Sun Jun 06, 2010 10:54 am

Thanks for the input Syncrozilla.
I know that you have experience with this setup and I remember something about the snap ring. I would have bought the front setup from you, but I was too late. If you are interested in having the front axles machined in the future so that I can build the fronts too let me know. I plan on adding a front locker on the van(as soon as I can find a decently priced one) and it will need the stronger syncro 16 front outers. Thanks.

insyncro Sun Jun 06, 2010 1:16 pm

syncrodoka wrote: Thanks for the input Syncrozilla. I would have bought the front setup from you, but I was too late. If you are interested in having the front axles machined in the future so that I can build the fronts too let me know.

x2

SyncroGhia Sun Jun 06, 2010 2:30 pm

Syncrozilla wrote: syncrodoka wrote: Interesting, I will have to track down some of those. Thanks


You don't need those. If your running the empi or sway away style axels they will just destroy those cups. Just put the flanges on clean and dry and fill the area inside the flange where the snap ring is with ultra grey RTV.

Also don't forget that something needs to be done to keep the axel from contacting the outer flange or it will wear a groove in it over time and the flange will break off the stub axel. On the sets that I have put together I have put a snapring groove inside the outer cv to prevent the axel from sliding all the way into the outer flange. Another idea I had was a teflon "button" on the out end of the axel. The button would screw into a threaded hole on the end of the axel. This is only an idea as I have not looked for someone who can machine up some teflon buttons.

The only trick to the fronts is finding someone with a good enough lathe to machine the axels to accept the outer cv joint. This is tough as the splined spring steel axels like to break tooling on lathes. I was told to not come back to a few machine shops before I found one who could do this work for me.

I presume this is due to their not being cut outs in the aftermarket flanges unlike the Syncro 16 flanges? I think I have both here at present so I'll try to take some comparison photos.

MG

syncrodoka Sun Jun 06, 2010 3:27 pm

I'd like to see some pictures. I have seen the different part numbers for the tranny flanges, but I have only seen 1 part number for the tranny flange cap.

Syncrozilla Sun Jun 06, 2010 5:29 pm

The aftermarket flanges accept the seal but RTV is much more reliable. Since the aftermarket axels have a long splined area they "float". This is necessary on cars with lots of wheel travel (off road racing) which is what these axels are designed for. When you hit a good bump the wheel traveling upward can cause the axel to contact the flange. This will put a small hole in the rubber seal causing trans fluid to get into th cv joint. Because of this all the off road racers don't use those seals. Ultra grey is simpler, less expesive and works better.

I'm happy to have some front axels made up for anybody who wants them. Pricing will depend on how many sets as the machine shop that does this for me charges me a set up fee. The set up is 75.00 and then it's about 75.00 per axel Plus the cost af the axels of coarse. I don't think I would have any time to do this until July however. I'm going on vacation in a week.

onwardtothestars Sun Jun 06, 2010 9:51 pm

SyncroZilla wrote:
The only trick to the fronts is finding someone with a good enough lathe to machine the axels to accept the outer cv joint. This is tough as the splined spring steel axels like to break tooling on lathes. I was told to not come back to a few machine shops before I found one who could do this work for me.

Can you elaborate on this a little?
I don't understand

syncrodoka Sun Jun 06, 2010 10:04 pm

Quote: syncrodoka wrote:

The only trick to the fronts is finding someone with a good enough lathe to machine the axels to accept the outer cv joint. This is tough as the splined spring steel axels like to break tooling on lathes. I was told to not come back to a few machine shops before I found one who could do this work for me.

Wrong syncro pilot, that was Syncrozilla that said that. 8)

onwardtothestars Sun Jun 06, 2010 10:18 pm

oops

SyncroGhia Mon Jun 07, 2010 2:40 am

Ok I think my aftermarket 108mm output flanges are at my other workshop but I have take a photo of the stock Syncro 16 output flanges instead and put it next to a photo from mccavittj earlier on as my other flanges are the same.





I was advised to clearance my aftermarket flanges before using them due to the differences and that the corners of the spider (central part of the CV joint) would catch when at extreme angles if I didn't. I haven't used them yet so haven't found out if this is a problem.

Oh just while I remember, the hub shaft flanges (shafts which go through the rear wheel bearings which your outer CV joint bolts to) have the same cutouts on a Syncro 16.

Something I have noticed on Limey is that when the rear CV joints move at extreme angles, the CV boots have a hard time coping and I'm going through them fairly quickly. It's pushing the rubber very close to the edge of the metal part which clamps the rubber boot in place and slowly wearing through the rubber. Does anyone recommend any other CV boots for 108mm CVs?

Cheers
MG

ajdenette Mon Jun 07, 2010 11:07 am

A lot of the dune buggy guys used the Porsch cv boots they are longer and arent quite the conicle shape and should also be avalible in the 108mm flange size.

syncrodoka Mon Jun 07, 2010 3:32 pm

Now I see what you are talking about. I've never seen real syncro 16 parts. Very interesting.

SyncroGhia Tue Jun 08, 2010 2:30 am

You can still buy these 2nd hand.
I had to buy these from Germany on ebay.
They're not cheap but they do come up for grabs.

Another way around this kind of issue might be to use CV joint spacers inbetween the CV joint and the flange. Porsche use these on 996 Tiptronics on wide axle cars like C4S and 996 Turbo.

MG

Syncrozilla Tue Jun 08, 2010 11:01 am

The flanges are not the issue. IT's the axel spline design that allows the axels to move much more than the stock axels. When the axel contacts the flange it does so in the center, right where that seal is. The only advantage of the stock flanges is that they run metric factory hardware and the aftermarket flanges use SAE bolts that you have to special order. I carry a spare set of CV bolts in my glove box. YOu could always run the factory 16" axels (assuming the length works with the 14" control arm) but you lose the advantage of the aftermarket "torsional" axel.

syncrodoka Tue Jun 08, 2010 2:20 pm

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. :)



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