How to get a 5.1 or 4.875 final drive for a R180 diff ?

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1600SSS72
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How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by 1600SSS72 » 20 Apr 2018 05:18

Hi, I have been using in my ´72 510 SSS a Subaru WRX R180 lsd 4.444, a big improvement over the normal R160 3.9 as I use the car for Historic Rallyes in Europe and I need quick response and top speed is not important.
I have the 280ZX FS5W71B gearbox with a Kameari close ratio gear kit that improved the big hole in 2nd/3rd and kept 5th 0.831.
But now I need to shorten final drive to 5.1 or 4.845 and I have been searching for several days and cannot find suitable Crown wheel & pinion gear sets.
I read that Datsun 720 4x4 diesel use front R180 in 5.1 and 4.875 but I was told they are short nose, so no good.
Do you have any suggestion? If impossible, will it be safe to ask a gearbox specialist to make a final drive ring & pin?
Thank you

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Byron510
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by Byron510 » 20 Apr 2018 06:18

The lowest ratio I’ve seen for an R180 is a 5.13, but I haven’t seen these for sale for 10 years and I was told that the teeth are getting so small at that point that the pinion year isn’t all that strong given the torque multiplication that is going on.
I know I have also heard d of 4.88’s out there, but I’m unsure of who made them.
Cal-Mini used to carry the 5.13 gear sets in the mid 2000’s, around the same time I bought my Percision Gear CLSD from them (one of the last ones available). A friend had them in his 85 720 4x4.

Keep up the search. Let us know what you find.

Byron
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because the opposite never works.

1600SSS72
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by 1600SSS72 » 20 Apr 2018 06:46

Thank you, Byron, I just sent an email to Calmini, I will let you know.

MK510
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by MK510 » 21 Apr 2018 03:15

720 4x4 front diff is long nose R180, bolt on to 510. European 720 2,5 diesel has 4.875 ratios.

1600SSS72
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by 1600SSS72 » 21 Apr 2018 08:59

Thank you MK510, I sent you a private msg

datzenmike
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by datzenmike » 26 Apr 2018 20:36

None of our Diesels were 4x4.

The '87-'89 4 cylinder Pathfinder WD21 had a 4.625 R-180 in the front but may be short length

The '80 Long Bed 4x4 did have the long nose R-180 in 4.625. I know of none above that number.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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Byron510
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by Byron510 » 26 Apr 2018 22:35

datzenmike wrote:
The '80 Long Bed 4x4 did have the long nose R-180 in 4.625. I know of none above that number.
It’s even more specific than that Mike; the 4.625 diffs only came in 1980 long box 4x4’s with the L20B in the first half on 1980. The second half of 1980 long box 4x4’s came with Z22’s and we’re 4.375 diffs.

Concerning diesel 720 4x4’s, I have seen only one - in a wrecker in Maple Ridge in the 90’s and it was a blue on Blue KC with a 5spd. I inquired about the trans but was told that the input shaft was bigger than the gas models and would t work in my 510, so I passed.

But you may well be right Mike, it’s the only 720 diesel 4x4 I have ever seen, and could have been an import.

Byron
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datzenmike
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by datzenmike » 27 Apr 2018 21:18

I have an '85 diesel 5 speed. Well in parts. The front case was donated to be used on a Roadster. (the starter is on the left and the bolt holes line up with the U20 block) with the front case you can 'graft' on a 71B or 71C body and gears. A great way to get around the scarcity of parts for the original Roadster 5 speeds.

The rear case was unavailable as I bolted it onto my '79zx 5 speed to get the shorter shift without shortening the shifter. (that's a story for another day)

The input shaft/spline is the same as all other Datsuns. At least, this one is.

All my info shows the Z22 began in July '80 or the beginning of the '81 model year. Ah there's the problem, a build date of July through December 1980 is actually an '81 truck.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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icehouse
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by icehouse » 30 Apr 2018 16:08

"People don't like it when shit doesn't match their rule of thumb." Sam

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Byron510
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by Byron510 » 30 Apr 2018 23:44

Unfortunately the Hardbody started using the short nose R180 in 1986, so the pinion gear won’t work. Or else we’d be all over that!

Byron
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icehouse
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by icehouse » 01 May 2018 08:59

Byron510 wrote:
30 Apr 2018 23:44
Unfortunately the Hardbody started using the short nose R180 in 1986, so the pinion gear won’t work. Or else we’d be all over that!

Byron
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"People don't like it when shit doesn't match their rule of thumb." Sam

datzenmike
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by datzenmike » 01 May 2018 21:04

Lengthen the drive shaft.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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icehouse
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Re: How to get a 5.1 or 4.875 final drive for a R180 diff ?

Post by icehouse » 02 May 2018 08:20

datzenmike wrote:
01 May 2018 21:04
Lengthen the drive shaft.
That's true. Might be worth modding the Xmember. Seeing how the removal of the rear diff is so painful. It would be cool to make it bolt from the bottom.
"People don't like it when shit doesn't match their rule of thumb." Sam

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