R180's and R200

[gramercyjam]

In San Antonio, TX

Pending the arrival of a new-to-me R190 4.44 Nissan Motorsports LSD, I am now divesting a small collection of R180's and R200's.

Here is the list:

2 each of open R180's - unknown ratio's - probably stock. 1 has relatively new side bearings and seals. Trade for beer

1 each of 4.1 VLSD R180 (never opened it up to verify - but currently in my car so I believe the ratio is correct. This diff is good and tight. $100 OBO

1 each of open R200 3.9 - At least this is what I was told - never tried it or opened it up. $100 OBO

--John B

[kmack]

I'll trade you an recently running (was pulled out of the car last month) '73 L24 for the 4.1 VLSD. Engine is minus manifolds and coolant inlet/outlet manifolds.

[gramercyjam]

That sounds like a good deal but I just sold the 4.1 and the dude was anxious. I checked and he already paypaled me. But I might be interested in the L24 anyway. What do you know about the L24? Did you get a compression check before it was pulled?

[kmack]

Damn! This is what I get for having to be at work!

Oh well. The L24 is the one that was in my car last month. I did not do a compression check, but it pulled 126.9 hp at the wheels back in July. There are a few valve seals that need to be replaced based on the little bit of smoke on start up. Front and rear seals do not leak. Pan gasket does not leak. Valve cover gasket needs to be replaced and 2 bolts on the cover will need to have heli-coils put in the head. (The thread are currently J-B weld but the heli-coils would be a better fix) Rear freeze plug in the block was replaced in March of '02. And I'm a little suspect of the rings in cyl. #3 but I have no current proof of that. (#3 cyl spark plug used to run darker than the rest about 6 years ago, but now is the same color as the rest - go figure)

[gramercyjam]

I'd probably be better off with a scratch built motor. I have a E31 that has all new stuff on it (including big valves and seats) for an L24 that I will be using. I also shaved it purposely to substantially raise the compression ratio so I will want the rings and bores to be in near new condition.

[bryantatem]

KMACK's old engine is a good running engine. I have driven his car and it does run really nice. Good engine. It gets my seal of approval.

[kmack]

WHAT!?! You drove my car? When?

:stupid:

Oh yeah...that's when my tranny blew out on the Exploder! :tapemouth

Duh!

[bryantatem]

KMACK-

you have spent too much time in the monkey cages...

I drove it to the San Antonio Car show

[kmack]

See? How nice of a friend am I when I'll let you drive MY car to a car show only because your's looked like... Well, I guess I shouldn't say that here, huh?

[Busching]

John,

Could you explain some of the terms and ratios...

z-car newbie :-(

Brent

[gramercyjam]

R180 style diff - smaller and lighter than the R200 styles. R180's are found in 240Z/260Z and some 280Z's. R180 denotes a 180mm ring gear.

R200 style diff - larger, heavier, stronger than the R180's. Found in some 280Z's and some ZX's. R200 denotes 200mm ring gear.

Gear ratio's denote the number of times the pinion gear (thus the crankshaft too) turns for 1 revolution of the ring gear (and the tires). The ratio is determined by the the number of teeth on the pinion gear vs the ring gear. Higher numbers better pulling power, increased torque at the rear wheels but reduced cruising speeds due to higher engine RPM's needed. Lower numbers mean reduced torque at the rear wheels but higher crusing speeds due to lower RPM's required by the motor.

Stock gear ratios are good for daily drivers. Competitive Z cars benefit for the increased torque from ratios of 3.9 to 1 and higher such as 4.1, 4.44 or even 5.88! There is an R190 5.88 on ebay right now. This ratio would be good for pulling stumps or perhaps cultivating a corn field. But that is a good price for an R190 limited slip differential. R190's are rare.

Limited slip differentials for Z cars come in 3 basic types, clutch, helical gear and viscous. Clutch type are the traditional mechanism that uses disks and springs to couple power to both the axels simultaneously. These are the type that Datsun/Nissan made for the 240/260/280 cars as add on racing parts. The clutches in these diffs eventually wear out and will need replacing.

Helical gear types, such as Quaife and Torsen couple the axels with helical gears and are the most expensive, but the most trouble free and generally considered the best type of LSD for road race and autocross competition. They are only available from third party manufacturers.

Viscous slip differentials use plates bathed in a fluid. When the wheels slip and turn a different velocities, the fluid heats up and pushes plates together that couple the axels. This type of LSD is better than no LSD at all, but not as good as clutch or gear type LSD's and not up to the tasks required of it in competitive situations.

None of the 240/260/280Z/ZX came with LSD's. Transmissions and differential ratios for Z cars can be found

here .

--John

[Busching]

John,

That was fantastic information!

I feel much more edu-ma-cated

I'll have to read it a few more time to completely understand it, but it was very valuable information!

So the R190 5.88 on eBay would be too torquey (sp) and not good for cruis'n around town? Just for drag racing? What would be it's top speed? Could it be used at highway speeds?

Sounds like the "1 each of 4.1 VLSD R180 (never opened it up to verify - but currently in my car so I believe the ratio is correct. This diff is good and tight. $100 OBO "

You have would be perfect?

How would I find out how my diff is currently setup?

How much does it cost to ship a diff? (to Washington State?)

We should talk more -email me - busching@hotmail.com

Thanks!