R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Engine, Transmission and related drivetrain.
demo243
Posts: 174
Joined: 19 Dec 2012 18:55
Location: Topsfield MA

Re: R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Post by demo243 » 11 Jan 2021 17:04

shaddai wrote:
11 Jan 2021 13:55
Previous owner was an... interesting... fellow. He fetched quite a few parts from other junkyard datsuns... L18 (from a truck?), 280zx five speed, and now the rear diff... so bizarre. This car has been fun to work on (for many reasons!). Who knows what else I haven't found yet that's different.
Thats the beauty of these cars! They are kinda like legos, you can build em one way, tear em down and build em another. And its amazing how many parts are compatible off other/newer Datsuns and Nissans!

L18, 280zx 5-speed, even the diff swap are not uncommon swaps. These 510s took a back seat to the Z cars back then so alot of the mods seem to have been out of need, availability and cheapness...
'71 4 Door - Street/AutoX/Track Day Romper - Carb'ed KA24DE

shaddai
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Joined: 05 Sep 2019 13:50
Location: NorCal

Re: R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Post by shaddai » 18 Jan 2021 13:30

Thanks all... my son and I jacked one wheel off the ground and spun it six times - the driveshaft spun a bit more than 12 times - per his calculations this means it's a 4.11 ratio diff. This certainly explains a bunch of things!

Now... time for a 3.9 or something. 4.11 is too high for my tastes, I believe.

datzenmike
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Location: Van. Isle.

Re: R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Post by datzenmike » 18 Jan 2021 14:26

You won't have much trouble selling a 4.11
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

shaddai
Posts: 47
Joined: 05 Sep 2019 13:50
Location: NorCal

Re: R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Post by shaddai » 18 Jan 2021 14:32

datzenmike wrote:
18 Jan 2021 14:26
You won't have much trouble selling a 4.11
Nice! That's probably the easiest thing, right? Find a new lower ratio diff and swap it in, then sell this one? Better than trying to regear?

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funwithmonkeys
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Re: R180 diff? Something seemed off and the car's geared really short... best avenue to fix?

Post by funwithmonkeys » 18 Jan 2021 15:16

There should be lots of 3.9s around. Selling a 4.11 should be very easy as Mike said.
If no one from the future comes back to stop you from doing it then how bad of a decision can it really be?

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