KAAZ R180 LSD fit problem

[Zed Head]

That's a bummer.  Here's a Hybridz thread that might be helpful.  Note also the part about the ring gear size.  Two different sizes for R180's.  Better check.

https://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

[Jeff Berk]

Thanks, I'm aware about the ring gear size issue because I had to machine mine on a lathe to get it to fit the LSD housing. I'm beginning to think the KAAZ LSD was designed for the Japanese market Z's. 

[Jeff Berk]

KAAZ tech replied that its a tight fit but I should be able to install the new buttons. 

In the mean time I found this thread:

https://ratsun.net/topic/23766-k-r180-411-swap-need-help-pics/

that shows how to swap the buttons from an older R180 to a K R180. The article also references the same thread that Zed Head posted but includes more detailed information on how to separate the spider gears from the R180 to get to the buttons. Specifically, it shows where the roll pin is located that I need to drive out.

[Jeff Berk]

I got the buttons on... I froze the buttons, heated the end gears with a torch, started the button with a brass mallet, and finally got out my 5-ton gear puller. I hope I never need to unbutton the LSD.

[Jeff Berk]

The LSD is installed and seems to be working smoothly and quietly!

Here's a summary of my experience installing the KAAZ DBN 2020 SQ in a Datsun 260z with an R180 differential:

Installation Challenges and Solutions:

1. Thread Buttons: The R180 differential uses side yoke bolts, while the DBN 2020 requires C-clips. Thread buttons are needed in the new LSD's side gears to adapt them to side bolts. Reusing the buttons from the original side gears might be more cost-effective and simpler than using KAAZ buttons (which lack splines).
2. Ring Gear Compatibility: KAAZ R180 units are designed for 115mm ID ring gears. Early US Nissans might use a 110mm ring gear. Machining the 110mm to 115.3mm on a 4-jaw lathe is possible.
3. Differential Case Clearance: The LSD will require grinding on the differential case for a proper fit. Use a Dremel or similar tool to remove minimal material, allowing the LSD to slide in end first then rotated for the ring gear to enter.

The KAAZ technical support team was very helpful regarding cooling requirements, which was the subject of a separate question I posted on ClassicZCars.com.

Hi Jeff,

 Thank you for the update.  I am glad that all worked out.

 As for the oil, an external oil cooler will be a big plus for cooling and extra oil capacity.

Under racing use, 80w90 GL5 will not last long.  Generally speaking, one weekend of drifting or two weekends of road racing will kill the oil.   We used to compete in Formula D and Time Attack series with our own Nissans back in the early days.   I have tried many different brand oil both mineral based and synthetic based.   At Formula Drift event, we had to change out the oil every day as the oil becomes like water after several runs.  Once the oil is done, the diff will start making lots of chatter noise.

For a daily driver and/or weekend spirited driving, the 80w90 will work fine.

Oil change intervals will be every 4-5,000 miles or when the chatter noise starts to get loud.

For this the Kaaz oil or the one from Torco works well.   For racing use, I highly recommend the use of Torco RGO GL6 85w140.   This oil will work well for most usages.  If using Torco, please add their lsd friction modifier Type F.  Heavier grade oil will last longer and more miles before change.  After we switched to Torco, the gear oil lasted the whole race weekend.

Kaaz unit works best with the mineral based gear oil.  Synthetic oil will not harm the unit but the operation noise might get pretty loud.

As for temperature, once it goes above mid 200F the oil will start to breakdown.

Best Regards,

Ray Nakadate

Kaaz USA

 

[Zed Head]

Does it have the new cover on it yet?

[Jeff Berk]

No, the new cover will have to wait a few months while I test the stock cover out and get an idea of what temperature it builds up to. Then I'll install the custom unit and try it with and without an air deflector.

From what I was reading, setting a clutch type LSD to 80 percent lock as I did will build up more heat than a 100 percent lock. I don't plan on playing around with the lock unless I have to because adjusting the lock requires the removal of the differential and all the parts that are in the way of the differential.  

[Jeff Berk]

Here's an update. I finally got to an Autocross last weekend to try out the LSD. I was delayed by a brake issue that kept my 260z up on blocks for a few months. The thermistor I installed in the differential drain plug did not show a significant heat buildup during the autocross. The temperature reached about 110F. The interesting part was that during the drive to the event, I drove at 70-80 mph for about 45 minutes. That built up a temperature of 230F. The KAAZ tech warned me that above 200, the oil will begin to break down.

I may need to install that finned diff cover which unfortunately means I need to modify some other components to get it to fit.