Thread: Blew my Diff .... :(

Originally Posted by Drover

Happy for ones more learnard than I to impart their knowledge . ..... But always to benifit of all to hear your technical explanation for you statements.

The size difference is surprising, half the reason why it's know as the plough...lol

Oh and the saying is " polishing a turd....."

Merry Xmas all !

Ok, so it sounds like you made your comment not knowing what a Sals really is. As has been pointed out many times on this forum, it is an English adaption of the famous Dana 60. It shares many physical similarites in the diff centre itself.

It is Hypoid just like the new Ashcroft HDP38. So the questions you need to ask to have the HDP38 any chance of being stronger than the Sals are:

What are the hypoid offsets? (the distance from pinion centre line to ring gear centre line)

What size are the ring and pinions?

What are the size and spacing of the pinion bearings?

What size is the output spline of the pinions?

What size are the carrier bearings?

Are material type and treatment close?

Gear design, is one gear design better(stronger) than the other? And if it is the smaller of the two, is it enough to make up the differnce in size?

Cast housings, is one prone to deflection more than the other?

Merry Christmas

Originally Posted by uninformed

Ok, so it sounds like you made your comment not knowing what a Sals really is. As has been pointed out many times on this forum, it is an English adaption of the famous Dana 60. It shares many physical similarites in the diff centre itself.

It is Hypoid just like the new Ashcroft HDP38. So the questions you need to ask to have the HDP38 any chance of being stronger than the Sals are:

What are the hypoid offsets? (the distance from pinion centre line to ring gear centre line)

What size are the ring and pinions?

What are the size and spacing of the pinion bearings?

What size is the output spline of the pinions?

What size are the carrier bearings?

Are material type and treatment close?

Gear design, is one gear design better(stronger) than the other? And if it is the smaller of the two, is it enough to make up the differnce in size?

Cast housings, is one prone to deflection more than the other?

Merry Christmas

Thats all good but the sals on the other hand has one very important weakness which is a show stopper which is well documented that the rover diff does not suffer from
Housing failure
And at the end of the day nothing is inderstructable
Ducking for cover

Originally Posted by rangieman

Thats all good but the sals on the other hand has one very important weakness which is a show stopper which is well documented that the rover diff does not suffer from
Housing failure
And at the end of the day nothing is inderstructable
Ducking for cover

Only when stupidly overloaded by muppets... and from what I've seen on the net only a few that have made good coverage because of the rarely of it happening... How many bent Rover casings have we seen on off road racers etc... Hundreds, but because its common, its no longer of interest... I've had many a vehicle with Salisbury's, the current one having 2, and I've never broken one. (Tho that could be about to change!! ). I've broken 60% of the Rover axles I've owned!

Originally Posted by rangieman

Thats all good but the sals on the other hand has one very important weakness which is a show stopper which is well documented that the rover diff does not suffer from
Housing failure
And at the end of the day nothing is inderstructable
Ducking for cover

Seriously, how many Sals housings have failed, world wide? Consider that they are not just in 110/130s, but in series III 109, Stage 1, One Tons, 101s and I think even in FCs?

I would bet money on more stock Rover assemblies causing a "show stopage" than Sals...

Don't see many posts with people saying I broke my Salisbury diff housing on the weekend.

They certainly can fatigue and break eventually I know one of the prime examples in a post on AULRO has done 800 000 ks of extreme work in Africa.
More disturbing was the one in the Kimberleys.

Originally Posted by uninformed

Seriously, how many Sals housings have failed, world wide? Consider that they are not just in 110/130s, but in series III 109, Stage 1, One Tons, 101s and I think even in FCs?

I would bet money on more stock Rover assemblies causing a "show stopage" than Sals...

Id have a broken Rover centre any day . At least with a stuffed rover centre the car can still be driven with a little bit of effort
Look personly i like the sals but you guys seriously take it all too personal that a sals is undestructable which they are not

Originally Posted by rangieman

Id have a broken Rover centre any day . At least with a stuffed rover centre the car can still be driven with a little bit of effort
Look personly i like the sals but you guys seriously take it all too personal that a sals is undestructable which they are not

Never said it was, and personally have never been a fan of the housing. Mainly beacuse of its shear size, weight and design. I have no fear about it failing in my enviroment either though. Maybe we are not saying that it is indestructable, maybe we are just trying to bring fact to these threads…

So on that note here is a little info I can add:

hypoid offset: Ashcroft HDP38 1.5 inch or 38.1mm, Sals 8ha 1.125 inch or 28.575mm

What does that mean, AFAIK, the greater the offset, the larger the pinion head becomes for a given ring gear dia. This means more tooth contact in mesh with the ring gear, which is stronger. I think it makes the pinion teeth physically bigger which is also stronger. But there is a trade off, the larger offset creates more thrust load (I think), is less effiecent (more heat build up) and I think weaker in reverse?

Ring gear dia: Aschroft HDP38 8.54 inch or 217mm Sals 8ha 9.75 inch or 247.65.

What does this mean, AFAIK the larger the ring gear dia, the larger the pinion has to be to suit. Since the Ashcroft HDP38 has a larger offset and the Sals 8ha a larger ring gear, we need a picture of both ring and pinions side by side to compare

Ring gear thickness: Look at the picture Ben posted of the Sals, now compare that to the pics of Ashcroft HDP38 ring gear. In my mind a thicker ring gear is going to less prone to diflection. Of coarse how it is fastened to the carrier ie bolt size, number of bolts and bolt PCD will matter as well. Maybe thickness allows a different tooth design? (pure speculation on my count, but given too little meat in the ring gear and I think it could limit tooth design?

Pinion diameter: Not sure on either of these. There is more than one measurement ato consider. Inner bearing, outer bearing and output spline minor dia.

Pinion bearing spacing and size, carrier bearing size: (note, not just dia but width). Again I do not have these. If someone can add them Ill edit them in here. Sals and Rover type for the carrier bearings as the HDP38 uses a Rover type centre.

Happy for any of the usual suspects to correct any and all info I have posted. Infact I would not take anything I have said as fact until it is confirmed or corrected.

Real men have 9 inches