There’s been some recent progress on the van project after roughly a year’s hiatus. We bought another van.
I saw this purple monster 91 E350 pop up on the 3rd Gen Ford Econoline Van marketplace for $600. It had a 351w/C6 combo in it that I wasn’t interested in. I just wanted it for the body. I offered the seller full price with the condition that he would remove the engine and trans before I picked it up. Money well spent. 1000 miles of towing on U-Haul and we now have a solid base to start the next phase of the project. I don’t have to deal with addressing all of that body rot now.
Towing a van shell with no engine/trans that barely fits on the trailer is a very stupid idea. I do not recommend it. I had to add 600 lbs of sand bags to the front of the trailer and engine compartment area to get the trailer to follow safely down the road. I drove 1000 miles/22 hours from North Carolina to Maine doing 50 – 55 MPH the whole way. Don’t be stupid/cheap like me, hire a transporter.
We want the van to be able to go everywhere and do everything that our Land Cruiser BJ45 Troopy can do. And we want it to go down the highway comfortably as well. With that in mind I’ve started ordering some components for the drivetrain. Last summer I bought the ZF 5 speed overdrive transmission with some of our Covid stimulus money. I recently ordered a Offroad Design Magnum Underdrive and a Gear Vendors overdrive unit. Yeah, that sounds crazy but there’s logic involved.
The Troopy can go many places most vehicles can’t go because it has front and rear locking differentials and dual low-range transfer cases. Air down the tires and it floats over sand. We want the same from the van. That’s where the Magnum underdrive comes into play. It mounts between the ZF S5-42 transmission and the NP205 transfer case. It offers two additional low range gear options. So we’ll have the stock NP205 1:1, 1.96:1 ratios and the 2.72:1 and 5.33:1 gears from the Magnum. In first gear, low-low the final drive ratio will be 125:1 with 4.10 gears in the diffs. That works out to about 0.8 MPH @ 1000 RPM (1ft of forward travel per second with 33″ tires). I think we’ll do OK on sandy beaches moving that slowly.
But going slow with good traction is only part of the challenge in getting the driveline setup properly. We do trips that take us 10,000 miles and a lot of time is spent on the highway. With 4.10:1 gears in the differentials the engine RPMs would be screaming if we were keeping the original C6 automatic. Thankfully we’re not 😉
The Gear Vendor’s overdrive unit replaces the fixed-yoke output of the NP205. (It’s only operational in 2WD mode, but we wouldn’t need and extra overdrive in 4WD.) It essentially changes our 4.10:1 rear gears to 3.20:1. Couple that with the ZF’s fifth gear ratio of 0.76:1 and our highway speeds with 33″ tires should have the 300 CID straight six running right in it’s peak torque range of 1700 – 1800 RPM. This will help fuel economy quite a bit and keep the roar of the engine down as well.
So the drivetrain stacks up like this:
300 straight six -> ZF 5 speed -> ORD Magnum underdrive -> NP205 transfer case -> Gear Vendor’s overdrive. I think this will be a great drivetrain for us. Not fast but reliable. It should be relatively fuel efficient compared to other rigs this size. I’m guessing somewhere around 20MPG unloaded, possibly better. We’ll find out someday.
It’s going to be 6 – 8 weeks before these parts start arriving. But I’m hoping to pull the rusty body off the 85’s frame and start prepping to swap the 4WD components to the 91’s frame.