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Drive shaft gap after 240sx Transmission conversion / swap in 280z


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So here's my question. I've read the AtlanticZ and the Motortopia (from Nigel)write up for the 240sx transmission swap into a 240z using the 240z-280zx manual transmission bell housing. I have a 1975 280z. The stock 280z FS5w71B transmission was 31". The 240sx FS5w71Ctransmission is 33". I also measured the transmission without the bell housing. 240z-280zx = 17inches. 240sx = 19 inches.

 

I shorted the driveshaft 2" according to the write-ups. I went to a reputable driveshaft shop in San Jose- Southbay Driveline(They do an awesome job btw).

 

They shortened it exactly 2 inches and removed the dust shield for me.

 

But now there is a gap where the drive shaft connects to the transmission. Is this normal? Did I just not notice the gap because the dust shield covered it before?post-1074-060267000 1324065793_thumb.jpg

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My highly honed opinion is... put the dust cap back and you'll be fine.

 

Thanks for the input guys. The dust cap had to be removed because it would prevent the input shaft from going into the transmission. The 240z-280zx drive-shaft dust shield goes on/around the older transmission end. Whereas the 240sx driveshaft goes directly in with no gap, and that small extra cylinder space in the end of 240sx tranny is the dust shield.

 

It does go in more than 50% so hopefully I'll be fine. Thanks again.

Edited by RTz
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Ah, the things you learn by test-fitting!

 

I fell into the same trap; but my FS5W71C was obtained from a 1987 200SX. My stock driveshaft fit perfectly, once the stock dust shield was removed. The dust shield on the rear of the transmission provides that protection now.

 

Your transmission is missing the rear dust shield, I would suggest replacing it.

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$50 at Inland Empire Driveline Service. Dropped it off on the way into work, picked it up at lunchtime balanced and repainted.

 

Making "one from two" was a little more since they supplied the new Chevy Tranny Yoke as well as a set of new U-Joints, $150 in 3" tubing. If I'd had the tranny yoke i believe it was $35 or $45 less. Basically weld the Datsun end on one end of the new 3" tube, and the Chevy end on the other. Straight steel driveshafts are CHEAP to get made. And quick!

Edited by Tony D
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280Z-75,

How much did the shortening cost you? I am going with the s14 trans and debating on either shortening my stock 73', or getting a new, early 240z ds from MSA with the spicer joints, depending on cost.

 

The shortening cost $135 at SouthBay Driveline. I called several shops around the bay area and $135 seems like the standard price nowadays. I was initially expecting about $60-80 since that was the qouted price in some old posts, but those prices are long gone. I dropped it off in the morning, and it was done by afternoon.

 

I wish I lived in SoCal to get the same deal as TonyD. I could almost have had 3 shortened drive-shafts if I got the same deal. $50!? When did you get it done?

Edited by 280Z-75
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Ah, the things you learn by test-fitting!

 

I fell into the same trap; but my FS5W71C was obtained from a 1987 200SX. My stock driveshaft fit perfectly, once the stock dust shield was removed. The dust shield on the rear of the transmission provides that protection now.

 

Your transmission is missing the rear dust shield, I would suggest replacing it.

 

 

THANKS! That would definitely close the gap. Didn't know that it was missing! I bought the tranny without it. I thought that it was just that 3mm space, but did a little searching, and now I see what you're talking about. Seems like the missing dust shield that should be on the 240sx tranny will cover up the gapped portion.

tranny with dust shield.bmp

no dust shield.bmp

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$50 at Inland Empire Driveline Service. Dropped it off on the way into work, picked it up at lunchtime balanced and repainted.

 

Making "one from two" was a little more since they supplied the new Chevy Tranny Yoke as well as a set of new U-Joints, $150 in 3" tubing. If I'd had the tranny yoke i believe it was $35 or $45 less. Basically weld the Datsun end on one end of the new 3" tube, and the Chevy end on the other. Straight steel driveshafts are CHEAP to get made. And quick!

 

How long ago did you get yours shortened?

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Less than two years ago on the shortening. Last December for the "two for one".

Off Smith & Commerce in Corona, or up in Ontario off Guadti. If you want Aluminum or CF, you have to go to the one in Ontario.

They are the place that makes the MSA aluminium shafts (at least they were), and you see them in Jegs, Summit, etc: "IEDLS"

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  • 4 weeks later...

THANKS! That would definitely close the gap. Didn't know that it was missing! I bought the tranny without it. I thought that it was just that 3mm space, but did a little searching, and now I see what you're talking about. Seems like the missing dust shield that should be on the 240sx tranny will cover up the gapped portion.

 

Looking at your pictures, they both look like they have no dust shield. You can get new dust shields from Courtesy Parts for ~$11 (part number 32135-Z31004 for the 85 300ZX trans). In use,they will actually be more like rock shields, since there is no matching cup on the drive shaft to keep water and dust out. It will look better, but could actually fill up with dirt and grime (call me a downer, sorry).

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I got curious on this so took some measurements on my car, a stock 280Z, and a drive shaft and transmission I have. I eyeballed the fit from under the car so not exact, but close.

 

The Nissan engineers left ~1.5" of space between the bottom of the drive shaft yoke sleeve and the end of the transmission output shaft. There's about 4 3/4" of spline in the sleeve, they use ~3 1/4".

 

That would be why the early 240Z drive shaft works, even though they're only 35 mm (~1 3/8") shorter than the later shafts. You should end up with ~7/8" of space between drive shaft and transmission output shaft with the early 240Z shaft.

 

 

 

Edit again - my numbers were off (happens often).

 

Edit again - see #18. Accuracy has improved by 1/8".

Edited by NewZed
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Did you have a shop modify the bell housing as well to fit the larger bearing and shift rod or you do everything yourself? Do you by any chance know what the overall shaft length ended up being? I got a 240sx tranny and driveshaft for free so trying to see what i can get away with since i dont have a S30 driveshaft anymore.

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I'm just swapping bearings for now. Boring a new counter-shaft bearing would require time and effort (= money) to get it right since it affects the location of the end of the counter-shaft. I don't have any power anyway so don't really need it, and it can be done later. I relieved the inside of the bell-housing for the drive gear behind the bearing myself, since it's non-critical, and drilled out the shift fork hole.

 

I managed to find an early 240Z propeller shaft. They are short enough to work but longer than recommended. The 240Z shaft is 21" between the centers of the u-joint caps (measured myself, couldn't verify anywhere before I got it). The stock 280Z shaft is 22 1/4" (verified in the FSM and my garage). You can see that I'm getting more accurate with each measurement. Obviously not a machinist, I'd never make it.

 

The 71C transmission is 2" longer than the 71B, that's why everyone recommends shortening the drive shaft by 2". I was just pointing out in Post #14 that's there's 1.5" of room for "error" or alternatives like the early 240Z shaft. With the early 240Z shaft, the driveshaft is 3/4" closer to bottoming on the mainshaft than with a stock shaft cut 2". 3/4" of clearance instead of 1.5".

 

If you're going to cut drive shafts you might consider combining a Z for the diff and the SX for the front. The dust cover will fit right. The diff flange bolt pattern is probably wrong on your SX shaft.

 

Wordy...

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Did you have a shop modify the bell housing as well to fit the larger bearing and shift rod or you do everything yourself? Do you by any chance know what the overall shaft length ended up being? I got a 240sx tranny and driveshaft for free so trying to see what i can get away with since i dont have a S30 driveshaft anymore.

 

You will need to modify your 280z or 280zx bell housing to make it work. Troy Ermish from Tracy, CA can get the machine work for a good price. He is also very experienced with this swap.

 

Information on the swap can be found here:

http://atlanticz.ca/zclub/techtips/240sxtransmissioninstall/index.html

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