Datsun Roadster Forum-311s.org

Does anybody know how much torque the rear axle can withstand without breaking?

Quite a bit. I think the breakage problems occur on re entry, after the tire lifts.

These axles have thee seasons on them,,,,and two driveshafts lol
Ted lost a diff in an SR20DET car after about 20,000 miles.

I read on Datsun1200.com that the diff can have 285 lb/feet and about - 300 hp, so I hope that the shafts can have the same force?

http://datsun1200.com/modules/mediawiki/?title=H190
The Hitachi H190 differential has a 190mm (7.49 inch) ring gear and can handle about 285 lb. ft. of torque, making it suitable for larger V6 or drag racing supercharged 1200s. H190 is the strongest live axle Hitachi fitted to Datsun cars (C200 from pickups is larger), and is available with lightweight aluminium carriers and a variety of stock ratios.

I've broken 6 or so over the past 16 years. They tend to fail in the splined area. My guess is that the failure is due to repeated shock and fatigue. I've had failures on 3 different axle housings. All the failures are identical. I doubt its from too much power, more likely from old age and lots of miles.

Will

Will, what kind of failures on the diff?

No failures of the diff, but the axles essentially shatter in the splined area. I can post pics later.

Will

I've had failures on 3 different axle housings?

Please, show pictures later, Will.

I've had 3 different axle housings on the car, and failures with each so the housings can't be blamed for the failures, unless all 3 have been bent, but I have to tire wear so I highly doubt that to be the issue. I've run the same diff for all of the failures however. Its a detroit locker diff so when one axle breaks the car will still drive.






Where the failure occurs in the diff.



these have been odd failures, I wish I knew what caused them.

Will

could it not be a bearing with to much play.
I hope it will not happen to me, we don't have new or used axels over here.
I saw you use a a locker diff, that could be the problem, my guess.

The wheel bearings have no play. They are correctly shimmed as well. The locker isn't the issue either. I've had a couple break within months of being replaced, others go years. There is no one side that tends to fail more than the other. I seriously think upgrading to new Summers Bros axles will solve the whole issue. I just need to get my hands on a set.

Will

I understand of what I read that this diff locks completely, that means that wheels can't slip anymore, so all the power will come on the axles.
Do others with strong engines have the same issues with the H190 diff, with or without a LSD, or are you the only one with this problem Will.

You will cry if you get the Summers axles and one of them break!! I know Ron runs a locker and he has never told me about issues with axles breaking so it might just be that the stock axles you keep running just can't handle the power.

Non stock U20 grabbing 2nd gear! Boom, Pulls a little to the side until I let off the gas .

Thought about stronger axles but I figure it would be cheaper to snap the axle than the diff.

SLOroadster wrote:I've had 3 different axle housings on the car, and failures with each so the housings can't be blamed for the failures, unless all 3 have been bent, but I have to tire wear so I highly doubt that to be the issue. I've run the same diff for all of the failures however. Its a detroit locker diff so when one axle breaks the car will still drive.






Where the failure occurs in the diff.



these have been odd failures, I wish I knew what caused them.

Will

Combination of old axles with a detroit locker diff.
Maybe another style of lsd diff will save the axles longer.

peter wrote:I understand of what I read that this diff locks completely, that means that wheels can't slip anymore, so all the power will come on the axles.
Do others with strong engines have the same issues with the H190 diff, with or without a LSD, or are you the only one with this problem Will.

Yes the locker locks under power, unlocks off throttle. A high breakaway point LSD is much the same as a locker, and it doesn't matter when going in a straight line. It really only matters through a tight corner, but in that event the inside wheel is largely unloaded, with the outside wheel doing all the driving. I've had them let go leaving a stop light, in a straight line, and only two times while autocrossing. (I think both times they were the outside wheel as well)

I think the issue is that the axles I've used either haven't been strong enough, or have had tons of miles on them before I started using them and I simply fatigued them till they broke. I think this is the more likely explanation. You need to remember all the axles are pushing 50 years old now. Good power with big sticky tires will only put more load on them.

Will