Outer Limits 4x4 Board

Check out this serious diff shave - talk about extra clearance!!!







http://www.pirate4x4.com/forum/showthre ... ge=2&pp=25

The oil capacity would be severely reduced though, so it probably wouldn't be practical on something that sees any amount of highway km's. The only option to compensate would be to place a new filler plug higher up, buit that would probably lead to endless hub seal or pinion seal leaks (and we all know that Rovers are bad enough as it is).

Any thoughts?

Thats a lot of cutting!

i believe that is a GM 14 bolt diff.

landy_man wrote:i believe that is a GM 14 bolt diff.

Yes I know that - but apart from it being a bit bigger than a D60/Sals there aren't too many differences - the principle is the same.

I did similar things to the flanges on my Salisbury/Dana60 front/rear combination and then realised it was a lot of effort for at best a 20 mm gain in clearance. but it did inspire me to goto a lot more effort for 118 mm.
Bill.

daddylonglegs wrote:I did similar things to the flanges on my Salisbury/Dana60 front/rear combination and then realised it was a lot of effort for at best a 20 mm gain in clearance. but it did inspire me to goto a lot more effort for 118 mm.
Bill.

Yes but I think the main benefit of this kind of shave is that you reduce the surface area on the lowest part of the diff. I have shaved my salisbury but this gives a big flat area at the bottom of the diff, and when it strikes a soft rut, rather than plowing through (like a rover diff) it just sits on the surface. I think the shaving method above would be better because it leaves a nice "sharp" bit on the bottom of the diff, good for "plowing" through the softer ruts that the diff strikes.

So you didn't have oiling problems Bill?.

The only oiling problems I had Ben was when i tilted the rear diff to get a better drive line angle on an 88 inch wheelbase and raised suspension. Salisbury/Dana's are a bit susceptible to starving their outer pinion bearings. I am convinced they would lubricate better if turned upside down as in 2 gear portal application.
Bill.

Thanks for the info. Speaking of portals Bill, do you have any pictures of the inside of the portal boxes from when you were making them. I am interested to see how the bearing mounts and other parts were made. I understand if you don't want to give away all your secrets...

I dont keep any secrets Ben. Unfortunately I havent taken any Photos of the internals yet. Coincidently I had both rear portals opened up last weekend, just to check how they were going and to see if the taper roller bearings supports for the portal gears had settled in at all. No problems on both counts. Next time I pull one down I will take some happy snaps.
The bearing housings were made from the flange and throat portion of old series swivel balls.
Regards Bill.

Cheers, Bill, some pics would be great. Two other questions, how much do you estimate each portal weighs, and how well does the oil stay in the right place? - do you get oil going into the portals from the diff?

With projects like these Ben it is probably better to pretend you never heard the term "Unsprung Mass", but all the internals for one portal box weighs 13 kg.s These consist of 4 gears, 2 gear carriers, 4 taper roller bearings, 4 bearing housings, 1 output shaft ( 101 pattern), assorted shims and spacers, bolts etc. The bare portal box that I fabricated from steel channel and flat plate would weigh about 3 kg's as it is mostly holes.
I think it would be easier, cheaper to make and significantly lighter by doing away with the full floating hubs and going to a semi floating design by shortening
something like Nissan GQ rear halfshafts for example.
To answer your second question, my portals are almost fully submerged in oil because I do not use seals between them and the diff housing. The double lip. double spring Rangey hub seals do a pretty good job of containing it all. Of course I have to make certain that the wheel bearings are always correctly adjusted, but due to the reduced loadings of negative offset wheels they rarely need doing.
Bill.