One Piece Driveshaft with 1310 U-joints

[R1dd1ck913]

Since I am having such a hard time with my non-serviceable drive shaft I have decided that I am going to build a one-piece driveshaft. This will mean no more CSB and no more flexdisk to go bad. I am going to keep this thread updated with my progress. And if it ends up working out well I might try and build a few and sell them. I think I can beat the 799 dollar one-piece that is for sell on line. The plan is to make it a 3 inch chrome-moly shaft with greasable 1310 U-joints. I used a driveshaft out of a 325is e36 in my m50/g240 car. So that will be what the one-piece will be based off of. Any questions please ask.

[R1dd1ck913]

Here is the differential flange and the first greasable 1310 u-joint. More coming soon.

[R1dd1ck913]

So Monday everything I ordered for my drive shaft will be here. The only thing I still have not ordered yet is the chrome-moly tubing. Any one know a reasonable place to get 3 inch .083 walled chrome-moly at? Local to Kansas City, Kansas or online is fine.

[totheredline]

Very interesting. I'm going to a one piece driveshaft using an lengthened one piece 325ix driveshaft. Mine won't be serviceable though. Butttt all in all I'll be about $270 into my shaft.

Sent from my XT1585 using Tapatalk

[R1dd1ck913]

Yea I will be close to double what you are spending. But even at that I will still be at less then http://www.driveshaftshop.com/ wants for a one piece. They want $799.99 for their drive shaft plus another 50 for shipping. I also belive I can build my one piece drive shaft better then they can. Only reason I say that is because they you an adapter plate on both ends of the drive shaft. Mine will only need one.

As for the IX drive shaft. The one thing that I didn't like about lengthening the IX drive shaft is that you have only one u joint on it if I am not mistaken. That will put a lot of strain on the flex disk.

[Northern]

Did you buy that diff flange somewhere? Or is that a one-off?

DSS seems questionable, I've heard a lot of balancing issues with their driveshafts from guys in the E30 community.

[R1dd1ck913]

The diff flange is a custom piece. But it is simple to make since the cnc program is already done.

The big problem I had with DSS is the fact you have to use and adapter on the diff and an adapter on the transmission. I am hoping that buy eliminating the adapter on the diff side it will help reduce any possible vibration. I am trying to come up with a replacement output flange for the transmission to convert the 3 bolts to 4 bolts with out the use of an adapter but I am not having any luck at this time. So for the time being there will be a adapter plate that will be used.

[AndrewBird]

Be cautious about this. A friend of mine made a one piece driveshaft for his E21 when he swapped in a rotary. He used tubing that was too small diameter (weaker) and at high speed on the highway, the driveshaft kinked, locking the rear wheels, making him spin out. He was very luck he didn't hit anything.

Carnage:

http://www.r3vlimited.com/board/showpost.php?p=2171173&postcount=120

New driveshaft and explanation:

http://www.r3vlimited.com/board/showpost.php?p=2305320&postcount=150

[R1dd1ck913]

I actually looked at that thread before. That thread is why I decided to go from 2.5 inch drive shaft to a 3 inch. Also made me decide on a chrome moly drive shaft since it should be stronger. Thanks for looking out for me anyways. Tomorrow I should have everything to put this together except the tubing. I am still looking for a place I can get the tubing locally.

[LJ851]

I actually looked at that thread before. That thread is why I decided to go from 2.5 inch drive shaft to a 3 inch. Also made me decide on a chrome moly drive shaft since it should be stronger. Thanks for looking out for me anyways. Tomorrow I should have everything to put this together except the tubing. I am still looking for a place I can get the tubing locally.

What is the critical speed of a 3" chromoly driveshaft at the length you need?

[R1dd1ck913]

If I am doing my math right. It is around 10,000 RPM. But I could be doing something wrong.

[LJ851]

If I am doing my math right. It is around 10,000 RPM. But I could be doing something wrong.

That sounds high to me, how long is your shaft (ahem) ?

[noid]

If I am doing my math right. It is around 10,000 RPM. But I could be doing something wrong.

If your engine is spinning at 7000rpm, and your gearbox in 5th gear is 0.81 ratio, that means your driveshaft would be spinning at 8642 RPM.

[R1dd1ck913]

Be cautious about this. A friend of mine made a one piece driveshaft for his E21 when he swapped in a rotary. He used tubing that was too small diameter (weaker) and at high speed on the highway, the driveshaft kinked, locking the rear wheels, making him spin out. He was very luck he didn't hit anything.

Carnage:

http://www.r3vlimited.com/board/showpost.php?p=2171173&postcount=120

New driveshaft and explanation:
http://www.r3vlimited.com/board/show...&postcount=150

I went back and read that post again. He said one of his CV joints locked up. So it was nothing to do with his drive shaft. What happened to the drive shaft was because of the CV joint locking up.

[TobyB]

Do the critical speed calcs- when I was futzing with this (2009) there were a couple
of online quickie calculators that agreed with each other, and with what Driveline Service
of Portland advised. Mine was for a 2002, and thus shorter than an E30, but was spinning
9k or so without problems. Tubing diameter is really important, more than you'd think.
More than I thought, anyways, and it was easy enough to go bigger.

If you could find an early flange, those are significantly bigger- and more stable for what you're doing-
than the later ones...

t