Portal kits on leaf spring vehicle?

[Ned Kelly]

I guess most of us have seen this portal kit in the making/offering now:
http://motorsports.axletech.com/portal.asp
About $6800 for all four corners I think was the estimate. Neat that they bolt on to existing D60 and 14ff outers.

Anyways, if one was to do this conversion, I was wondering how well an old school leaf springed vehicle would handle this in terms of axle hop? That additional leverage would induce axle wrap - yes? no?

Maybe DIY4x4 Wraptor setup would help the rear stay 'hop-free'.

I think the Volvo C303 had leaf springs with portals. If I recall it was in spring under axle configuration vs chevy leaf spring over axle.

I've also read that portals don't lend themselves to highway speeds (ok up to 50mph or so) due to heat build up in the portal reduction boxes. Supposedly that is one reason Unimogs aren't highway friendly.

 

[Stomis]

IMO its much cheaper to just buy mog axles. Your taling $100 for a 14b, $500 for a d60 then those portals. Ouch.

Any additional unsprung weight will increase axle wrap so I would say coils at least upfront would be in store for a swap of that caliber.

 

[Hogback Fabrication]

With the springs on the top of the axle tube of a portal axle, you will have to deal with tons of axle wrap. This is for the same reason that lift blocks create axle wrap problems; they move the spring way above the axle centerline. This creates lots of extra leverage on the spring and hence, axle wrap.

To talk about something as extreme as portal axles and then still consider using leaf springs is silly IMO. Yes, I'm sure some of the OEM portal manufacturers used them, but they also probably used leaves with a SUPER high (stiff) spring rate (and hence had very little flex) to counteract axle wrap problems.

 

[runamok151]

my friend is running mog 406s under his bronco. 3 link front he used 2" dom, .250 wall and 1.5" heims. he's broken the links/ rods twice. the new rods will be 2.5", 3/8" wall with 2" rod ends.

he's leaf sprung in the rear w/ an anti wrap bar attached to the pinion bolts. he originally used 1/4" plate for the piece that attaches the anti-wrap bar to the pinion. he gets so much axle hop and wrap, that he ripped a 6" wide piece of the plate where its bolted to the pinion. he now has a 1/2" thick plate there. the new truck he's building will be 4 linked.

the problem w/ mog axles is a) they have a very long pinion where the torque tubes attach. this needs to be cut down for drive line angles. b) the diffs are offset alot more than domestic axles and the axle tubes and shafts have to be custom cut. $$$

 

[Hogback Fabrication]

my friend is running mog 406s under his bronco. 3 link front he used 2" dom, .250 wall and 1.5" heims. he's broken the links/ rods twice. the new rods will be 2.5", 3/8" wall with 2" rod ends.

Did the rod ends break? Or did the links break at or right next to the welds?

I'd be REALLY surprised if he was able to destroy 2" .250" wall DOM in tension or compression.

Which also makes me wonder about link placement, portal axles use a whole different set of calculations. Maybe his link placement is putting tons on stress on the upper or lowers?

 

[runamok151]

the rod end broke just outside where the insert was welded and the tube bent.

this is the first time he did it.


pics of the aftermath

he did it again about a month ago but i don't have any pics. his 2 biggest problems with this truck is weight and limited space. even though it's narrowed front and rear and gutted of everything he doesn't need, the full exo makes it very heavy. plus he's only running about 2" lift (+5" for the portals) so he's severely limited on where he can put links. it does not flex well, so i'm sure there's binding putting rods and ends under extra stress.

he's currently building and early bronco (smaller & lighter) it will be built w/ the bigger mog axles (416s?) and like i said, he's going up to bigger/ thicker links. the differences in the frame will let him 4 link it front and rear.

here's an example of the axle hop he gets when he drives hard

 

[runamok151]

i just got off the phone w/ my friend. they are 1" rod ends that he's been breaking. he just bought 1.5" evolution rod ends for the new build/