Lsd identification and questions

[DavNova]

Recently bought this, identied as a h190, possibly with r180 plates. 

Full album: http://imgur.com/a/WdOsYmw

 

Have a 79 620 rear end I'm wanting to put this into. (SR20 powered)

Didn't know if anyone had any information if this was indeed a nismo unit or not, and if I shouldn't use these possible r180 plates? Maybe use r200 plates instead? 

Also saw in other threads a spacer might be needed for the bearings.

Any help or advise is appreciated.

[datzenmike]

Count the side gear splines. Should be 29 for trucks.

 

This isn't a Nissan LSD by the looks of it although the plates and clutches do.

[DavNova]

Yes 29, initial torque is said to be 22-23 lbs, which seems to be low.

[datzenmike]

That's what the soccer-mom's later Pathfinders were. They didn't like the chirping hopping tires turning corners on pavement in a 'truck' that never saw a dirt road. So Nissan trimmed 100 pounds off the break away force.

[DavNova]

I'm reading up on shimming to increase, there seems to be a wide range of opinions on streetable torque numbers. Some say 45, 75 or up to 100. I may try 60ish as long as it all fits with no issues. 

[datzenmike]

Weight and traction are important. Has to be enough of both to overcome the clutches so they slip and uncouple when making a turn. Too much break away needed and you may as well weld it solid. Too little and there isn't enough lock up to be effective in a straight line. 

 

The '88-'93 D21 Hardbody had a CLSD option. If you can find a factory service manual on line it would show how to check the break away torque with a torque wrench for a 2wd truck. The Hardbody would be similar to the 620. If you don't mind pulling the differential apart to get what you want I guess this won't matter. I had an '82 Grand Prix Pontiac with LSD. It was un-noticable when driving around town on pavement, very light setting. On soft surfaces like sand, mud/dirt or snow both wheels would spin.