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rb20 flywheel & 350z clutch with n/a 280zx 5-speed?


subtle_driver

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Hi guys, I spent some hours trying to find this clutch trans and flywheel combo but couldnt find a confirmed answer.

 

I have a 73 240z with l24 and 280zx non-turbo 5-speed transmission. I'm currently using a stock l24 flywheel and clutch. I kept a stock rb20det flywheel off of the rb20det i sold. My goal is to install an l28et (automatic) into my 240z with this rb20 flywheel and a 350z clutch. My concerns are it will not clear the bell housing, too big for starter to line up and im not sure if my current release bearing/collar will work properly. I want to get this done in one shot if possible :

 

so to make it simple for others who are searching this option:

 

my setup:

 

73 240z,

l28 turbo engine,

280zx 5-speed non-turbo (nissan transmission NOT borgwarner)

280zx clutch release collar 90% sure, (not 100% confirmed, possibly stock 240z)

 

 

I would like to have it ready for a gettaway car on my wedding in about 3 months on a tight budget. I'm also having a heck of a time finding l28 turbo to 240z install write-ups with lots of pictures :( been searching google and here but i must be a freakin' idiot since i havent found anything with lots of pics and wiring help for days. (very frustrated)

 

thanks for your help!

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The rb20det flywheel will fit and mate with the starter. The L-series, KA, and RB20/25/30 flywheels all have the same dimensions and crank/clutch mounting holes. The only difference is the friction surface diameter (L24-28 N/A and KA are 225mm; L28ET, 260/280Z 2+2, and RB20/25/30 are 240mm).

 

If memory serves from when I did the KA24 trans swap on my 280Z, I believe the T/O bearing collar needs to match the clutch used. Given that, I'd imagine that you'd need to use the 350Z collar with a 350Z clutch, but I'm not certain. If you have all of the parts available, the easiest way to check would be to measure the thickness of the 350Z pressure plate, compare that against your 280ZX pressure plate, and use the appropriate collar to make up the difference (if any). I think there are at least 3 different collar lengths among these clutch/trans combos.

 

This is a popular flywheel/clutch combo in the KA/240SX realm. Someone on those forums may be able to tell you definitively which collar you need.

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Wow, thanks for the information!!! I was worried about the pressure plate fitting in the 280z bellhousing, I also deal with subaru and the sti clutch was too big to fit the wrx trans... better to ask than find out the hard way.

 

I also want to swap a 240sx trans, was it hard?

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It's pretty easy if you're handy. I did mine in half a day using these two resources as guides:

http://www.motortopia.com/cars/1973-datsun-240z-11118/car-pictures/240sx-transmission-swap-14041
http://atlanticz.ca/zclub/techtips/240sxtransmissioninstall/index.html

There's basically three steps:

  1. Modify the Datsun bell housing/case to accept the 240SX trans
    • Drill out top shift rod hole to 16mm (or hog it out with a 5/8")
    • Grind/mill down inner countershaft bearing boss
    • Swap front countershaft bearing from Datsun trans to 240SX trans, OR bore Datsun case to accept larger 240SX countershaft bearing
  2. Modify trans crossmember
    • Cut the center out, move it back 1.5", weld it back together (it's a little different for the earlier 240Z, but your '73 has the same crossmember as my 280Z)
    • If you're weary of welding, I believe the McKinney RB or KA swap tubular crossmembers would bolt up.  And, if you have deep pockets, Kameari makes a square tube crossmember specifically for this swap.
  3. Shorten driveshaft
    • Have a driveline shop take 1.5" out of the total length
    • OR, if you can find one, the earlier '70-'71 240Z driveshaft is short enough to bolt right up

 

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Be careful with aftermarket RB flywheels...there are some that actually register on the 36mm small pilot on the crank, like the KA flywheel does, and they are cut oversize to fit over the end of the crankshaft. I have one of these and needed to bush it down 0.75mm to get it to fit properly, but it balances out very nicely and accepts the 250mm clutch disk with no issues whatsoever.

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