Jeff Berk

This is an aside for those installing an LSD in their R180. It came to my attention that R180 ring gears were provided in 110 and 115 mm IDs in the US. The KAAZ model DBN2020 LSD that I purchased was designed for the 115mm. I had to enlarge my 110 ring gear so it would fit on the KAAZ. It took me an hour to mount the ring gear perpendicular to the lathe axis and another hour to carve out about 5mm. The ring gear is incredibly hard steel. Lucky for me there was a knowledgeable machinist available to help me.

This is an amazing project I'm glad I didn't attempt. I have two potential avenues of assistance if you need either one. My fall back mechanic for my Z, Lanny Ritz in Kent, OH can handle just about any issue with a Nissan, except he doesn't do differentials. I can get you the contact information he ships his differentials to if you get into a real bind. If you need help cutting out a shim, I have access to a water jet. You would just have to ship me the stock.

How many years until you can call them NOS (New Old Stock)?

Your machinist's comment about tolerances might explain why when I tinker around at a machine shop at the university, I'm forced to convert all my projects to inches from metric. This thread has convinced me NOT to pull out the pinion on my LSD upgrade. All this trouble just to get the right shim is not worth it.

You are a few weeks ahead of me. I couldn't find anything on the internet about rebuilding a R180 so I was using the instructions for a R200 at: Like you, he also used gear marking compound. I purchased a KAAS 1.5 LSD and it just shipped last night from RHDJapan.com (model DBN2020SQ). I'm reluctant to remove the pinion shaft because I'm not sure I can get the lash correct when I reinstall it with new bearings. I'm looking forward to how it goes with your build. Please keep us updated.

If you contract with an upholsterer, you can select just about any fabric you like. Or, if you are like me and have your heart set on a specific pattern, take this as an opportunity to learn upholstery. I'm doing that with leather so I can cover my dashboard.

I went with leather and I'm happy with that. Otherwise, I'd suggest finding an upholsterer to create a new cover.

I think zKars is right. It's hard to say where the differential came from because the R180 was switched out with an R200 in the early 1980's but some time after that, it must of got switched back to an R180.

I'm trying to determine the gear ratio on my R180. There is a number on the ring gear of ?? x 394 Does this mean 3.94:1 ? Should I just see how many turns of the differential input is required to make a full revolution of the ring gear? Can anyone assist in decoding this? Jeff

Thank you

Thanks all. I'll check to make sure the 1/2 shafts are operating smoothly and if not, I'll dive into rebuilding them.

I'm removing my differential to install a LSD*. While at it, I was looking to see if I need to address anything else in this 49-year old car. I've seen detailed videos on rebuilding half shafts and was wondering what could possibly require rebuilding on them since there is so little movement this component needs to experience. The universal joints appear to be fine so far. *BTW: I decided to go with a KAAZ unit because I like their technical support, ability to adjust (although not easily) and I found a great price including shipping if I order them from a Japan-based vendor. Jeff

Has there been any updates on this project since May?

OK, not prefect but close. I'll post the obj file tomorrow if anyone wants to make one or two. I printed it in PLA, sanded it, sprayed it with a few layers of gloss, then stretched chrome vinyl film over it. I will print the next one in ABS because this one warped a little when I heated up the vinyl wrap to stretch it. The photo shows the original one in my hand and the printed one installed. It looks like a chip is missing in the printed one but that's just some strange reflection.

Well, if you think you might need a hitch, go for it. I don't think I can afford a drive all the way to AZ for this. I suspect it should be almost exactly what is on a 240z.

I think its an April '74 (VIN RLS30019158). My Z spent much of its early life in AZ with an previous owner.

I was looking into installing a hitch to tow a support trailer for Auto-X and checked with U-haul and got a strange response that I cannot act upon since I live in Ohio.

The OBX LSD ebay listing indicates that it fits the 84 to 89 300ZX. As far as I can tell, I have a R200 out of a 280zx so it should NOT fit my differential. But, from what I read in a posting here on ClassicZ is that the difference between 84 to 89 R200's and the 75-83 R200's is that the 75-83 R200s used a ring gear bolted to the carrier with 10mm bolts while the ’84-89 used 12mm bolts. In the video by Stewart Motoring, he had used bushings to fit the 10mm bolts into the 12mm holes. Does that mean that all I need to do is purchase the same bushings he did from McMaster Carr and that will adapt the LSD to my ring gear? I'm assuming that I can retain my existing side shafts or half shafts (whatever they are called) between the rear wheels and differential. NEW TWIST: The vendor shows the OBX unit is out of stock but he has MHP LSDs at the same price.

Going back to the LSD option, I found this OBX on e-bay from what looks like an authorized dealer. https://www.ebay.com/itm/185599652068?fits=Make%3ANissan&hash=item2b3699f0e4:g:vqgAAOSwhrFjNjda&amdata=enc%3AAQAIAAAA4MIe6Uoer6SZ0hsN5krJSbV4iFzg4hk%2BAWSrQNuI663pte0VClGAiTftyVKD9QBBi5zpeWVgyuK7X8d5qM%2FvG4Fo2gXX2RUObNdHtG7D73Mo9nfI0dJ%2Byd593rpBfvqSsa06fVSNP9akt2sG6CZD7DFkwHTKIkLlpH1aKehC0cNbptijaXZ0q2oTs7O8rOM1knezPhA2heLZqUcojkWuFCv528k9hwvcmaAXmIzBdy8Glh3gTCT%2FOHue2Fql5GMDzkHZlZnI6Rfj5h2XZdh9jjET%2B9q3StxSl37CyBSmwgLf|tkp%3ABFBMhuTRzfZi I think my differential is an R200 out of a 280zx so I'm assuming this unit will work. I understand that I'll need some ancillary parts like shims, but I can use my existing axles. I've been reviewing the following youtube video which seems informative (how did we survive pre-youtube?).

I've never touched the castor and camber, just the toe in using a tape measure and two aluminum plates. I'll need to read up on the other two adjustments.

Perhaps breaking loose is the wrong words. I get tire screeching and oversteer both right and left. I understand that oversteer is inevitable when the car is pushed beyond its limits. I want is to expand the car's limits. I thought sticky tires was my most cost effective way to do this but now it sounds that an LSD might be the way to go. My suspension configuration is as follows (italics indicates early 1983 owner upgrade based on documents that came with the car.): 1) Technics front/rear anti-sway bars (links and bushings replaced 2018) 2) Quick steering knuckles (I have no idea what this is) 3) FIA Nissan Racing Calipers (4-pistons) 4) KYB front/rear struts (2018) 5) 1-1/2 inch lowering Eibach Performance Spring Kit (2017) 6) Front strut tower bar

It looks like my best option to control my car around the sharp Auto-X turns would be to install an LSD. I'm tabling my tire upgrade for now but if I go back to it, I can always buy a full set of 4 and car-top two of them. Documentation from the owner back in the early 1980's listed the front brakes as FIA Nissan Racing Calipers (4-pistons). I don't know how to differentiate this unit from a Toyota 4-piston so I'm assuming it is still the current unit. I'd like to keep my costs to around $500 +/- so if I go with an LSD it looks like it might have to be the OBX unit. I started looking at videos on its installation. I have access to some uber-gear-heads in my area for support if I get stuck (R&R Restoration & Repair in Kent, OH and Case Western Reserve University's [ThinkBox] machine shop, Cleveland, OH). I've been avoiding the Toledo auto-X because of its distance and my concern over the reliability of my car (see my initial post about break downs). I think I have issues sufficiently under control now and my daughter's family live 5 miles from the Toledo airport and could come to my aid if I get into trouble so I might risk it next season and see you there grazyZlair.

No LSD. Just an R200 installed in the early '80s by a previous owner.

I've tried Auto-X three times but my car broke down due to vapor lock once and a damaged battery cable another time. I made it home eventually under my own power. This past weekend I got a successful 8 runs in at Dragway 42 near Cleveland, OH. The event took place in their parking lot which is a lawn area crisscrossed by pavement. This was their last event of the year so I'm making plans for my 260z's hibernation upgrades. One issue I'd like to address is rear tire grip. I've tried lowering my air pressure to 28.5 psi in the tires all around but my rear tires could still use a little more grip. I'm currently using Kumho Ecsta AST KU25 All-Season 225/50R15 91H which are performing well on roadways. I started looking at a track tire alternatives that I can switch to for auto-X and came across some 225/50R15 Hoosier R7 with 3/4 thread remaining on usedracingtires.com at $100 each (plus shipping). I am likely only able to haul two extra wheels in my '74 Z so unless I want to risk driving with these slicks on the public streets, I would be limited to switching out only one axel at the auto-X event. Now the questions: 1) Are there any issues with using my Kumho tires in the front and these Hoosier slicks in the rear? 2) Has anyone had experience with usedracingtires.com? 3) Since I'll be purchasing a pair of steel wheels to go with the track tires, should I stick with 15 inch wheels? I'm not sure what width and setback are needed for stock fenders and lowering springs, factory drum brakes in the rear. Thanks for reading Jeff

In my latest attempt at logging tens of hours into refusing to spend $30 and up for parts that should cost <$10, I'm focusing on recreating the chromed plastic cover over the top bolt holding the arm rest onto the door of my 260Z. The part was reportedly never offered on its own and is NLA except as a reproduction. One of mine broke in half and the other is almost at that point. https://www.thezstore.com/product/1517/door-armrest-chrome-finisher-74-78-260z-280z I'm playing around with creating a high quality 3D scan, printing the part with a 3D printer, and coating it with chrome. So far I've attempted with a scan using my Android phone, then a $1K+ stand alone scanner. The print is close to being where I want it. I'm going to try and chrome it using chrome vinyl film like what's used in vehicle wraps. I'm posting this to force myself to following through. I plan on posting the final obj file for anyone wanting to print one for their own use. The attached early attempted scan obj file can be opened in MS Paint 3D for viewing. 3DModel_LowPoly.obj