One Piece Driveshaft with 1310 U-joints

[iansane]

I was under the impression you want a little offset between the diff and trans angle... 1-2* or something?

I just had a local shop make a 1pc driveline with 1310 u-joints and uses the DSS adapter (that used to be a bit cheaper now that I look at it, http://www.driveshaftshop.com/drives...50-flange-2348

I think I spent 250 for the shaft? It's a 3" shaft however, the balance weights scrap the gas tank as the DS spins so I had to hammer the tank a bit.

[mohmoh62]

Pretty!

I had real trouble with the slip joint, I have to warn you-
it would never balance properly.

I finally gave up and went to a fixed- length tube, and that was much better.

fwiw,
t

The slip joint being on the shaft and not the yoke means it will move in and out while rotating...causing the vibration yes? Any update on how you're worked / if it vibrates or is perfect?

I have that $800 DSS one piece and I've spent two years off and on trying to figure out the vibration. It's so bad I don't drive it much anymore, especially not over 60. I've replaced all bushings and mounts in the driveline, swapped transmissions, transmission flanges, diffs, even checked the vertical angle of the diff and trans... Within 0.1 degree of each other.

[R1dd1ck913]

Yea I get that. How often will I pull the drive shaft. Who knows. I just like to have options.

[TobyB]

I'd giggle about that- I mean, how often do you have to pull the driveshaft?
but then, I spent a good part of April 2009 doing just that- put it in at the shop,
take it to the track, take it back out, turn it around, do the hokey- pokey, send
it back to Portland...
It really sucked. I learned a lot. The hard way.

Next time, if there is a next time, I'm doing it the easy way.

Whatever THAT might be!

t

[R1dd1ck913]

Sounds like yours might have been built with a 16 spline slip yoke. I will agree that I could not find a good 16 spline slip yoke. Every one I looked at had some kind of play. I ended up going with a 32 spline slip yoke and it fells as tight as can be. I mean no play and it slides nicely. I'm really hoping this works. I'm not oposed to having to do a fixed length shaft. I just don't want to pull the diff every time I need to do something to the drive shaft.

[TobyB]

Not very many, if I recall. Umpteen? DSP did it, and they used a 'decent' but not 'super'
part. It had measurable deflection, which, in this case, was too much.

I had other concurrent problems that didn't help- but after I solved them, and
got it smooth with the fixed length shaft, I tried going back, and the slip joint vibrated.

Just what happened to me, in 2009...

t

[R1dd1ck913]

How many splines did the slip yoke you used have?

[TobyB]

Pretty!

I had real trouble with the slip joint, I have to warn you-
it would never balance properly.

I finally gave up and went to a fixed- length tube, and that was much better.

fwiw,
t

[R1dd1ck913]

The rest of the flanges and what not showed up today. I ended up with one of them being wrong. So I have to send it back and get them to send me a new one. Just one more delay. I did how ever order the tubing for the shaft. I did some new numbers on shaft critical speed with a 42 in tube and I am coming up with around 12,500 RPM so I should be safe since the drive shaft should never make it over 9000 RPM

[TobyB]

Ah, whups, I missed the m50/g240 part in your op. I was thinking 260.

sorry,
t

[R1dd1ck913]

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

I don't have an exact length yet. I am hoping to know tomorrow what the exact length is when the rest of my flanges and the slip yoke show up.

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.

This is basically the same thing I got. I also tried 7200rpm with a 5th gear ratio of 0.80 witch came out to 9000rpm. So at lest I got something right.

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...

Every critical speed calculator I have done for the different types of tubing that I have considered using have been at lest 9500 RPM or higher. The max speed I would be spinning the shaft at is 9000 RPM. And that is pushing the engine to 7200 RPM in 5th gear. I will keep an eye out of a bigger flange but I have been reading mixed things about putting different flanges on a g240.

[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

[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.

[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.

[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) ?