It's been a long time coming, but with the engine management and wiring harness sorted out, we could finally justify turning our running, driving J2000 into a driveway ornament for a week or two while we yanked the stock 232, T-14, and Dana 20 drivetrain in favor of some more modern components.
We've been calling this project J2008, reasoning that it's what we'd like to see Jeep offer if the company was still building fullsize pickups. In reality, we're just wishing for better power, drivability, and mileage. And there's no denying the ease with which a 4.0L replaces a 232 or 258 inline-six. Skipping the V-8 allows you to retain the factory six-cylinder radiator, hoses, motor mounts, and engine brackets. And we were shocked to discover we didn't even have to drill new framerail holes to retain the factory crossmember. But you can read all about that elsewhere in this story.
Check out some of the finer points of bolting a modern 4.0L, NV3550, and NP208 into a vintage FSJ in this issue. Next time we'll be wiring, fueling, and firing the beast as well as finishing up a few odds and ends necessitated by the drivetrain swap.
Naturally, the first step...
Naturally, the first step is to remove the stock engine, T-case, radiator, and everything else. The NV3550 that we're using requires a hydraulic slave cylinder to actuate the clutch. With the engine compartment cleared you'll have plenty of room to mount the clutch master cylinder on the firewall. We made a template and found the best spot actually located off an existing bolt hole.
We drilled the firewall with...
We drilled the firewall with a 1 1/2-inch hole saw and then bolted the clutch master cylinder on. After inserting the pushrod, we cut and drilled some 1 1/4-inch angle iron to lower the pushrod mounting position on the clutch pedal as shown.
Advance Adapters supplied...
Advance Adapters supplied us with all the factory components we'd need to mate the NV3550 to the Jeep 4.0L bellhousing, including a new clutch slave cylinder, throwout bearing arm, and throwout bearing. We soaked the oil impregnated bronze pilot bushing in engine oil overnight before installing it in the 4.0L crank.
We bolted the bellhousing...
We bolted the bellhousing to the tranny, then lightly greased the input bearing retainer, pivot ball, and contact points of the throwout bearing before assembling the parts onto the tranny. Don't use grease on the pilot tip of the tranny or it can mess up the oil impregnated bronze pilot bushing.
You can install the clutch...
You can install the clutch cover plate after the flywheel is installed, but it's much easier to put it on beforehand. We torqued the Centerforce cast iron 4.0L replacement flywheel on and then, using a clutch alignment tool, installed the Centerforce II clutch disc and pressure plate. The Centerforce II disc grabs like gangbusters and offers exceptionally long life for a daily-driven application.
In prepping the engine for...
In prepping the engine for installation, we discovered that while the driver-side 232 engine bracket bolted right on using the older engine's 3/8-inch bolts, one of the passenger-side 4.0L holes was drilled and tapped for a 12mm fine-thread bolt. We drilled out the one hole on the 232 bracket a bit larger and then bolted it on.
Since our stock 232 motor...
Since our stock 232 motor mounts were literally falling apart, we ordered up some polyurethane replacements from Daystar, which are the same as those used in Jeep CJs. We also ordered up a TJ tranny mount for our NV3550. The poly bushings may transmit a bit more vibration, but their long life and strength will ensure we never have any tearing issues given the flexible frame of the FSJ.
With the engine brackets,...
With the engine brackets, clutch assembly, and other accoutrements bolted to the 4.0L it was little work to sling the 4.0L home into the FSJ engine compartment using the factory 232's motor mount location. Note the clearance between the intake manifold and the brake master. On certain power brake-equipped models it may be necessary to swap to a booster with a smaller diameter, but we had plenty of room on our manual-brake rig.
With the engine bolted in,...
With the engine bolted in, we heaved the NV3550 into place. We did remove the shifter tower for floor clearance, but it unbolts easily and uses a nice rubber O-ring gasket that requires no sealant. Note the great shifter positioning. Our rebuilt transmission that Advance Adapters supplied is out of a Liberty and the shifter cane is angled back farther than the shifter on a TJ or XJ tranny. The angle works, but had it not we were planning on replacing the factory shifter with a short-throw B&M or Hurst shifter.
Rather than using the cheesy...
Rather than using the cheesy factory plastic hydraulic lines from the clutch master to the slave cylinder, we always prefer these braided lines and brass fittings from Advance Adapters. Advance offers a short extension line, but our application didn't require it.
You need to grind a very small...
You need to grind a very small bit off the tranny case to clear the slave cylinder's AN fitting. We lubed the supplied rubber O-ring with brake fluid, pressed the fitting into the bore, and secured it with the supplied roll pin.
You must bleed the slave cylinder...
You must bleed the slave cylinder before installing it in the bellhousing. We extended the piston and filled the bore with brake fluid, then attached the hose to the master and slave. With the master cylinder filled, depress the pushrod a couple times to purge the air, then depress the pushrod and reattach the plastic bands before bolting the unit to the bellhousing. The bands will break once the clutch pedal is depressed.
The Dodge NP208 bolted to...
The Dodge NP208 bolted to the back of the NV3550 like a dream. We wanted the T-case on before we figured out the tranny mount so we could take the driveshaft angles into consideration. As it turns out, our '68 J2000 had factory mounting holes for the stock tranny crossmember which positioned it right under the built in tranny mount of the NV3550. Our only issue was that the crossmember was a bit low for the driveshaft angle we wanted.
To raise the T-case up to...
To raise the T-case up to where we wanted it, we cut off the integral studs of the adapter plate Advance Adapters supplied so we could use it as a spacer. The additional 1/4-inch dropped the Daystar poly tranny mount just enough to reach the crossmember. We drilled four new mounting holes in the top of the crossmember to accept the TJ tranny mount and then bolted everything together.
While everything bolted together...
While everything bolted together with no cutting or welding, we'll probably need to address the wide gap between the front T-case flange and the crossmember. Chances are the front driveshaft is going to hit the crossmember when the suspension drops out. We won't know for sure until the driveshafts arrive. Tune in next time to find out.