Dual purpose NPR 4x4 build

[DzlToy]

Absolutely brutal!

Matt is taking the truck to the dealer tomorrow for them to check out a noise in the rear diff and a noise at the front right tire/wheel. After he gets the truck back from them (hopefully repaired), we hope to start on the flat bed and the 4WD conversion. He has the front axle already (one ton Chevy D60) but it needs to be rebuilt. It is 1/4" wider (spring perch mount) than the factory Isuzu springs, so he will just make a spacer for it where the springs attach to the frame. If that is not feasible, new spring hangers are not a problem at all.

We talked to EC about the Radflo shocks they are using on the Fusos and while there is nothing COTS for a DoKa NPR, it was reassuring to hear the ride is almost car like from a new EC FX owner. We have some contacts at Fox, so will be looking into that as well. The rear will probably end up links and bags and the front may get custom springs from Deaver, Alcan or Betts.

I would not want to do much on that engine through the floor panels at all. Lifting the cab with the shop crane or a forklift may be worth it for anything other than minor repairs. It's kinda like building a ship in a bottle and removes one of the majour advantages of having a COE truck IMO.

 

[dlh62c]

Find a local CAT scale and weight the truck. Using a air pressure/axle weight table for your tire brand, you might find that you can reduce the air pressure to 45 psi or even lower in the rear duals and maybe 55 psi in the front. The reduction in tire pressures will make a world of difference in the ride. There's no need to be running 90psi without a body on the back.

 

[DzlToy]

Matt and I had that discussion on the way back from OvEx last weekend. I run 45 or so in the 07 FE Fuso and it's better, not a Lexus, but better than 80 PSI with a light weight flat bed on it.

Hopefully the flat bed will be on the NPR soon and we will work on pressures then.

Cheers

 

[SkiFreak]

Does the cab tilt forward on these 4 door trucks?

I have not seen this myself but know that there are setups for tilting the cab that use hydraulics.
As mentioned, accessing the engine through the access hatch is a bit of a pain, especially when compared to the access you have when you tilt the cab.

 

[matt t]

Update

So things have been crazy busy at the shop, however I am tired of looking at the NPR in the corner. I am going to start the 4x4 conversion today. I came across a new, never installed F350 Dana 60. Since it has bushings on the axle for radius arms, I am going to make use of them. Still debating on whether to go with radius arms or 4 link. I will be using coilovers. Should have the axle under it and ready to go in a couple of weeks as long as we do not run into anything unforeseen.

 

[matt t]

Should be about 8" taller. Going with 35" or 37" tires.

 

[45lpv]

Excellent news. I was wondering about you guys just the other day.

I still want to come visit sometime this year to check the place out.

Jim

 

[justbecause]

next time I am in clarksville could I come see this?

 

[matt t]

Sure thing.

 

[justbecause]

:smiley_drive:

I'll be watching, I'll send you a PM next time I get to head that way, its not real often, but we have friends over there we like to see when possible.

 

[4x4coaster]

Nice project!
Now that you are using the f350 front I presume you will use the matching f350 single rear axle.
What diff ratios are you using?

Make sure your mounting design for the front diff allows adjustment for caster angle too.

 

[justbecause]

Nice project!
Now that you are using the f350 front I presume you will use the matching f350 single rear axle.
What diff ratios are you using?
.

Plans for now are to keep the NPR rear axle with 5.13 gears and use the OEM LSD. i am not sure about the front locker choice ATM.

.

an f350 SRW axle would be a several thousand pound rating down grade.

 

[pappawheely]

Is the bolt pattern the same front to back?

 

[matt t]

Not sure on the rear axle yet, I will not be using the factory Isuzu axle. The bolt pattern will match, it will probably be a dana 80 or AAM 11.5. The front axle has a 4.30 gear.

 

[Family Friendly 4x4]

Wicked little truck you have there.

We also build a removable body for our Fuso to be dual purpose. I used hydraulic cylinders but there is no reason you cannot use electric jacks it will be great.

Looking forward to seeing how you get on with it.