I'm currently gearing up to do two diesel conversions. The first is a military truck GM 6.2L diesel engine into an International Scout. The second is the SD33T from that International Scout into an AMC Eagle. I've started a project thread here on the forum but its stagnant until I finish the 401 5 speed SX4.
First thing, own a diesel before installing one. My SD33T Scout is my daily driver while my SX4 is apart. It requires incredible patience. You will be willing to pay the extra cost of fuel if you are in a rush. It doesn't start instantly and its bad to turn the engine off instantly. (I idle for at least 20 seconds to keep hot oil from cooling and congealing around the turbo bearings). It accelerates worse than an Iron Duke no matter if you are empty or hauling. No matter how much horsepower you have, a diesel engine will not increase its RPMs faster than a given amount. Power to wieght ratio by itself doesn't make it a race car. If you don't plug in the block heater for at least an hour, it will smoke obnoxiously for several minutes and have absolutely no power until it reaches operating temperature. I always idle for 10 to 20 minutes at the start of each trip.
I obviously like it enough to spend the time and money in putting it in an Eagle, but the end product will be drastically limited in application. My 4.5L inline six or 401 V8 Eagles are considerably more practical and fun to drive across any situation. A daily driver needs to give the option of jumping in the cab, turning the key, and throwing a rooster tail out the driveway. A pregnant wife in labor will not want to sit and idle for five minutes. If you are a typical Eagle owner, you bought the car for less than a grand and figure on spending less than six grand the entire life of the vehicle. I'm not typical. I've spent 23 grand for a 2006 Unlimited Rubicon and I am willing to spend that or more if it makes my Eagles more fun to drive, more reliable and capable, and more practical than the TJ. I'll spend at least 12 grand on each of several Eagles. Do not consider a diesel conversion if you think it will save you money on fuel. Only consider it if you're passionate about the advantages and willing to spend much more time and money on the car than it will be worth when its done. A fuel injected 6 cylinder is simply the most for your money and few people need to look further.
The 6.2L GM conversion is a better conversion than the cummins options in several ways, even tho the cummins diesels do beat the GM 6.2 and 6.5L in horsepower per unit displacement. I went with the GM anyway because it is essentially a small block Chevy that runs on diesel. Its got plenty of power and torque and they are easy to find. All the military Chevy blazers and Humvees are equipped with them. The military trucks have 24 volt systems, but most of the truck uses standard 12 volt parts. The dual 12V alternators have to be uncoupled and the starter replaced with standard civilian parts and you're good to go. Cummins and Ford diesels are just as easy to find, a little more powerful, a little more expensive, and so far a toss up against the GM diesel.
I've found the transmission to be the hardest part of any conversion. Thats where the GM diesel has a profound advantage over any other. If it works with a SBC, it works with the 6.2L. Any motor can be adapted as easily as the next, its the transmission that makes or breaks the conversion. The Jeep 4.0 is the only engine you'll find with compatible front axle mounts. Its the only cheap and simple option to modernize and provide respectable power to an AMC Eagle. With an AMC V8 an adaptor is available to buy. Once you look past those two options, you're accepting the chore of fabricating new motor mounts or doing a straight axle swap. The front axle is the profound difference between an Eagle and every other car ever made. It has a huge impact on the complexity of an engine swap.
There is alot of aftermarket support for people putting SBC motors in Jeeps. The GM diesel shares the same motor mounts, bellhousing, and flywheel as a 454 SBC. Since the flywheel is neutrally balanced it can be swapped with any SBC flywheel. A 154 tooth SBC flywheel is the biggest that can fit in an Iron Duke bellhousing. Thankfully someone else has done it before, so I know the stock Iron Duke starter is said to work well with a Chevy flywheel. Using that bellhousing opens up the full range of available Jeep transmissions and keeps the hydraulic system totally stock. It eliminates a great deal of adaptor cost and complexity. I don't trust a T5 behind a diesel, but I do trust the NV3550. That's easily adapted and compatible with stock drivetrain parts.
If you're going automatic with the GM 6.2L, the best choice is clearly the four speed GM transmission. An expensive adaptor ($420) is available for the necessary Jeep transfer case. The previous owner of my Scout has driven an SD33T with TF727 three speed automatic, and he hated it. The three speed gearing is too narrow and the necessary axle ratio to match the gears to the engine torque curve demanded an overdrive that wasn't there. Thankfully my GM 6.2L will marry beautifully to a readily available four speed automatic.
I'm going with the SD33T in my AMC Eagle because I have two of them, they last forever, they've got lots of support through the Scout community, and its externally the same size as the AMC 258. Its not enough power to keep me happy in the Scout, but its a perfect match for an Eagle. It will fit considerably easier than the GM motor because it has only one exhaust outlet on the driver side, just like the 258. Eagles have an engine offset to the passenger side that is very hard to deal with. The NV4500 is overkill, but its the only five speed available for the SD33T. The axles will be upgraded to handle the torque and the 33 inch tires. It will not be a daily driver, but it will be wicked cool.
Topic: Howdy. I got the shell of an 81 SX4 (Read 10529 times)