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Umm I just killed my R200


Garrett76Zt

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The R-200 “should” be stout enough for Garrets ride, (AWESOME time slips and dyno chart BTW, good work.)

 

Testimony to the toughness of the R-200…

JnJdragracing is running 9.2 @ 153 MPH in the ¼, full on wheel stands in an early Z car with a 1.36 second 60’ time. Over 700+ HP from a blown N2O fed V-8 using the STOCK Datsun rear end and suspension, R-200 diff, U-joint half shafts, Energy suspension bushing of the control arms and mustache bar, etc. They recently switched over to the 300ZX CV’s….

 

http://www.jnjdragracing.com/ourcar.htm

 

 

http://forums.hybridz.org/showthread.php?t=112868

 

There are times when an R-200 will just fail, though not related to HP. I’ve broken an R-200 with my stock cammed N/A L-28, though the engine didn’t break the diff. The roll pint hat holds the shaft that the spiders rotate around fell out,, the shaft then “slotted” the spider cage, lots of shavings in the oil, clunked pretty bad till finally the shaft broke in half and part of it flung out and lodged in the case while backing up. I’ve sent that happen to a couple other early R-200’s as well.

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There are times when an R-200 will just fail, though not related to HP. I’ve broken an R-200 with my stock cammed N/A L-28, though the engine didn’t break the diff. The roll pint hat holds the shaft that the spiders rotate around fell out,, the shaft then “slotted†the spider cage, lots of shavings in the oil, clunked pretty bad till finally the shaft broke in half and part of it flung out and lodged in the case while backing up. I’ve sent that happen to a couple other early R-200’s as well.

The failures that I've seen on Hybrid Z are:

The roll pin retainer bolt thing comes out.

The cross pin wallows out the hole in the carrier.

The cross pin slides halfway out and beats the hell out of the inside of the case.

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unfortunately for me, they seem to last alot longer on the automatic cars since they can preload. Like I said, I'm gonna give it another shot I think mine just had a hard life and it was time.

 

Thanks for your insight Jmortensen, I havent done much work with diffs yet. This was the stock one that came in my 280.

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Ok I just got it out and Mr. Mortensen is correct, it looks like the cross pin decided to free itself and bang around inside. The potentially good news is that the ring gear appears to be undamaged as does pretty much everything else. I guess the only damage was to the cross pin itself which I'm guessing is not a big deal.

 

So my question is, do i spend the time pulling another diff from the JY. Or can I just replace the cross pin and be on my way?

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From what I've read I would take a close look at the hole in the carrier. It tends to wallow out and get oblonged. If that's happened to yours, forget it. You could use another open carrier in that diff though. Maybe get someone who is installing an LSD to send you their open. You might also think about welding the cross pin in place.

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LOL, right again Mr. Mortensen . . .

 

I just took the carrier out and took the ring gear off. WAY oval shaped. The roll pin has one end completely snapped off. Like I said the ring gear and spider gears look to be in good shape although the pinion gear has some wear on it. I'm thinking it would be better off just replacing the whole thing. Unless someone has a 3.54 carrier they wanna send me . . .?

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3.54 open R200

 

I'm like 95% sure its dead. I dont see anything crazy happening with the CV's and this is some LOUD clacking and binding happening right in the center of the rear.

 

To be fair I've been pulling shavings out of this diff for over a year now. I dont think its liking my current power/torque.

 

Is this gonna keep happening or was it just time for mine in particular?

 

I'll try to get some pics tomorrow. . .

 

If its an open diff expect it to last for about 100 runs or so. Ive broke 4 of them now. Its the PIN that breaks in the center of the gears. If we could get someone to fab a billet pin replacement they may last alot longer. I am looking into that when I get back. The rest of the diff is just fine, its just that damn pin that breaks..

 

Terry

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I've got a theory:

 

When you launch the torque transfers through the ring and pinion and into the carrier. Now the side gears want to turn the wheels, but there is a lot of resistance to movement from the tires. ANYTHING that can move before the wheels start to turn is going to move. The side gears have a little slack and will move just a bit, and load up the smaller pinion gears which puts pressure on the cross pin shaft. I think that repeated shock loading distorts the case, and this causes the slack in the gears to get worse, which causes the case distortion to get worse and worse, faster and faster. Finally it breaks the roll pin and the shaft starts to slide out and beat the crap out of the case and then it breaks in half.

 

I have no experience, but I think that if someone took the time to WELD IN THE SHAFT ON BOTH ENDS, this problem would be for the most part eliminated. Best to pull the shaft out, grind a bevel on the ends so that the weld was stronger, then weld it to the carrier. If that is possible, and I don't see why it isn't, then I think that would make it a lot stronger.

 

That's my theory. Care to prove me right?

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I just swaped my 3.54 for a 4.11 R200 the other day. It's my spare but i'm willing to give it away for 20 bucks if you pay for shipping.

 

Its in perfectly good shape. But, for the price of shipping, you might as well just find one local. anyway its just an offer if you need it asap.

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hmm thats good idea . . .

 

once the roll pin is out/broken should that shaft slide out easily? Obviously mine has taken a beating but it doesnt slide out even when i try to beat it out with a hammer/screwdriver.

 

Once I go pick up a new one I may try welding the shaft in like you said.

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