Nissan Solid Axle Swap

[burkeee]

Been a few days now working on the steering box relocation.



New mount is plated on the box side, with the back holes sleeved and a plate on the opposite side of the frame as well. The front section of frame is only C channel, so the inside was reinforced with plate where the front bolts go through. Should be a good solid mount.



The pitman was drilled to fit the insert, and the steering mocked up. We ended up having 4.5" to move the axle forward. There is about 3.5" of clearance between the tie rod and bottom of the frame, which we measured out and should be enough up travel to stuff the tires fully.



Have to stuff a panhard bar in there between the tie rod and axle, as well as the mount for the upper link on top of the diff. This is where the huge joints are going to hurt



I think having cheap, easy high steer is the best reason to use a toy axle over a dana in this case, even with the extra work of flipping the housing.




We picked up some PVC pipe to mock up the links with, rather make a $1/ft mistake than a $10/ft one. We'll start mocking them up later this week.


Paul

[burkeee]

Now that the axle is in position, we cleared out some crossmembers and exhaust that were in the way and started measuring for links. I entered them into the 3-link calc to get an idea of the geometry.



My anti-squat (actually anti-dive since its in the front) is good, and the frame side upper is going to be adjustable to fine tune things a bit, since the calc probably isn't right anyway. The roll axis angle is a bit high, but since its a steering axle that amount of flex steer may not even be noticeable. The upper link could be a bit longer to keep the pinion angle better during droop, but the trans x-member will be in the way if the mount goes back any more.

The former torsion bar mounting x-member was a convenient place to mount the lowers. I cut out some tabs to fit the poly chev spring bushings that we're using on this end of the links.



I'll add a bracing plate across the top of the tabs when I weld them solid.



The tcase is in the way, so some of the frame mount for the torsion xmember had to be clearanced.



Mock up link in place to check the fit.



Axle brackets we were able to buy ready made, worth the $15.



Lower link all mocked up. We bolted the spindle and tire up to check the clearance between the link and tire, and everything looks good.



The upper link is next. We have to re-do the trans xmember to allow for the driveshaft that will actually need to move up and down now, and the frame side link mount will be integrated into that.

We also checked the axle at full stuff to see how much room there is for the panhard... Going to be just enough between the top of the pumpkin and the oil pan to fit it between. We'll leave that for last



Paul

[rallyroach]

Made some good progress yesterday!

Are you planning to beef up any of those factory crossmembers?

[burkeee]

I think the crossmember should be up to the task, the torsion bars have a lot of force on them too. I'll probably brace around the tabs a bit.


Paul

[Rue]

Lookin good.How long are the lowers,they look long.


Rue

[johnvon]

I think they measured close to 40" long.

[nissannut]

Lookin good.

Have you decide were to mount the upper link? I think I am going to move mine. I need to understand that calculator. I get some wheel hop on steep hill climbs.

[burkeee]

We figured out the mounting of the upper link today. Started by cutting out the brackets for the frame mount. The new plasma cutter is quickly becoming my favorite tool in the shop.



The mount will sit above the frame some, as close up to the floor as possible. There'll need to be lots of stuff added to the bracket to solidly attach it to the frame, we'll figure that out after we finalize where everything is going.



Cut the tabs for the axle end mount.



Here's roughly how it'll fit. I'm going to have to build some sort of small truss across the top of the housing, to fit the tabs. The panhard takes up all the real estate directly on top, so the mount needs to push backwards.



Only need a fit and driveshaft and exhaust in there now




Paul

[nissannut]

Thats gonna be tight! I am thinking about shortening my upper link. Right now its right below the exhaust and clears fine. But I was think of a shorter one that will allow me to raise it higher. I hope that will help with the wheel hops.

Did you see how King and roastbeef did theres? I basically copied kings 3 link and made all the links longer.

[burkeee]

Yeah, tight for sure. There is plenty of room for the driveshaft, and I figure we can route the exhaust where ever we can squeeze it.

You need to consider caster and pinion angle changes during travel when figuring link lengths. Equal length upper and lowers will give you no pinion angle change, but lots of caster change (death wobble), good for buggies but not road driven rigs. A general consensus is to make the upper 70% the length of the lower, which minimizes caster change, but does allow the pinion to drop during travel, which might bind the driveshaft at full droop. Shorter than 70%, the driveshaft will bind sooner because the pinion drops.

I have seen roastbeef's sas, and I don't see any point in doing all the work to make a short arm setup. It's basically the same as a stock jeep setup, which every jeeper is looking to upgrade to long arms. When you get higher lifts, the angle of the links is really steep, and the anti-dive numbers go up causing hopping, weird braking, and all the other stuff jeep guys with short arm lifts complain about.

The calc is used mainly to find the anti-dive #s (which is anti-squat because the calc is assuming your doing a rear setup). A 100% anti-dive means when you hit the brakes, the front doesn't dive, which is a bad thing because weight doesn't transfer and your front brakes are less effective (and weird climbing behaviour). Race cars look for anti-dive of around 50%, which gives max braking and stability. For a road driven off road rig, 50-70% is said to be good enough. A tall short arm jeep I've heard is around 80-90%.

But just having long links doesn't necessarily solve anything. I can see in your setup the upper link frame mount is low, below the frame. If you put your link #s into the calc, I think you would find high anit-squat. There is all sorts of info on the calc and how to use it on pirate.


Paul

[Kenzie]

so where's the best place to get a high steer for toyota and is it the ifs steering box that ya use ?

[burkeee]

We've gotten a lot of stuff from Trail Gear Canada and had great service from them. They're out in Vancouver, but shipping is pretty cheap, and no boarder fees etc. I would really recommend them.


Paul

[burkeee]

We haven't got a tonne done latley, but John has been picking away at things like cleaning up the frame and cutting the material for links. Tonight we managed to get all the links mocked up.

Droop to the floor.











Flexed out.





Full stuff.












We measured 14" of travel from full stuff to sitting on the floor, but I doubt we'll be able to use that much. Caster change goes from +5 deg at ride height, to +8 deg or so on the floor. The pinion angle looks ok through the travel as well.

Next step will be to mount the coils and shocks, then wind the panhard bar around and through everything.


Paul

[rallyroach]

Man, that is some sick flex for a street-driven rig. nice, very nice ;D

[Rue]

Very nice! Cann't wait to see it in action ;D



Rue