Measuring drive shaft

Engine, Transmission and related drivetrain.
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slowerthantime
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Measuring drive shaft

Post by slowerthantime »

I'm measuring the drive shaft to have it shortened. Should the yoke be fully inserted in the transmission or is there some allowance for float? If so, how much? Cheers.
datzenmike
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Re: Measuring drive shaft

Post by datzenmike »

Stock F4W63 4 speed ......... 26" long
Stock FS5W71B 5 speed....... 31.5"

The difference should be around 5.5 inches shorter if for a 71B transmission.

I assume the drive shaft is measured from the center of the U joints. See if your driveshaft agrees with what I wrote down years ago...

510 sedan......... 42 9/16" or 42.5625" or 1081.08 mm
510 wagon........ 48 7/8" or 48.875" or 1241.425mm
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
slowerthantime
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Re: Measuring drive shaft

Post by slowerthantime »

Thanks Mike. Transmission is 31 3/8" and the drive shaft is 41 1/2" centre to centre on the U joints, +/- pilot error.

I suppose my question is: Does the yoke need to have some available travel when installed in the transmission and if so, how much?
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JordanTr
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Re: Measuring drive shaft

Post by JordanTr »

Yes it needs a bit since the engine and trans will move forward and aft a small amount. You also need some extra room to be able to move the shaft into the trans to get the pilot seated at the tail flange. IIRC, I’ve used about 1/2”-5/8”.

If you don’t specify, driveline shops often give you lots of travel since they are accustomed to working on live axle stuff.

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bertvorgon
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Re: Measuring drive shaft

Post by bertvorgon »

I concur, I have about 1/2", never had a problem.

Make sure...THEY make sure the universals are uniform in the yoke. Datsun/Nissan used to provide shims in their universal joint kits, to make sure that was the case, basically saying that one side is not offset a hair from center. Seen that on drive shaft balance issues in the past.

I wonder if the tail shaft bushing is still available? Likely not. I put a new one in mine may years ago and that also eliminated an and sort of micro wobble there too.

My drive line is very smooth at 8,000 in 5th, given Andy made my driveshaft in the lathe. I have NO balance weights on mine at all.
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datzenmike
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Re: Measuring drive shaft

Post by datzenmike »

slowerthantime wrote: 09 Apr 2021 17:40 Thanks Mike. Transmission is 31 3/8" and the drive shaft is 41 1/2" centre to centre on the U joints, +/- pilot error.

I suppose my question is: Does the yoke need to have some available travel when installed in the transmission and if so, how much?
Your driveshaft already has this clearance. All that's needed is shortening it the difference between transmission lengths. Tell the driveshaft shop to shorten 5.5"


Go with your 41 1/2" center to center. The one I posted is 10-15 years ago and I have no idea what they measured. Perhaps the outer edges of the yokes?
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
slowerthantime
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Re: Measuring drive shaft

Post by slowerthantime »

Thanks for the info.

Mike, I made a typo. My driveshaft is 42.5" not 41.5"
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