SWAP SUGGESTIONS, RULES & RECOMMENDATIONS
BY Fred Williams
PHOTOGRAPHY FRED WILLIAMS
SINCE THE DAY THE FIRST production 4x4 rolled off the assembly line, gearheads like us have thought we could do it better. In fact, we can only imagine the young GI back in World War II telling his buddies how much better his jeep would be for battling Nazis with a V-8 under the hood. No matter how well the OEMs do, we’ll always want more power. Engine swaps are an innate part of our genetics. Sometimes we want more power, or maybe we just want more reliable power and torque. Off-roaders, like our hot rod brethren, are notorious for “taking a perfectly good vehicle and messing it up,” if you ask an OEM engineer. We think of it is making it better.
Swapping an engine into your 4x4 shouldn’t be taken lightly by the newbie four-wheeler. It’s not an afterschool project that you’ll have done before Mom calls you in for dinner. It can go smoothly, but it can also be so frustrating you’ll end up selling your project truck undone and in disgust. Trust us: We’ve seen it many times. In fact, it often leads to a very cheap project truck for the next guy.
On the other hand, there is a lot of aftermarket support for those of you looking for something better or just different under the hood of your wheeler. There are tired and true recipes, of course, but nowadays with the Internet there are also opportunities to try more oddball swaps because you can usually track someone down online doing the same thing to share ideas with.
We’ve thrown together some pointers, products, and info as a basic starter for engine swaps, but as basic as this is, we’ll bring you even more in part two next month. Remember, the more you research before you start, the more likely you’ll get that new engine in before Mom calls for dinner.
1 Swapping an engine can require a fair number of tools. For example, an engine stand from Harbor Freight Tools is much easier to support an engine than trying to hold it yourself.
2 We are building another wacky Jeep machine, this time a CJ-10 cab on a stretched TJ chassis (read more about CJ-10s this month, page 42). The engine is a Chevy 6.0L engine with a 4L80E transmission we bought used from an ’02 2500 Suburban. To swing this drivetrain into our Jeep, we found that the Harbor engine hoist with the air-actuated cylinder works better than a pet elephant or an engine hoist with a hand pump.
3 By the time we bolted a four-speed Atlas transfer case to the back of the 4L80 transmission we had a very long drivetrain. We had tried maneuvering it with the hoist and a chain, but it didn’t go well.
4 Next we tried the new Pivot Plate from Mac’s Custom Tie Downs. This bolts to our 6.0L engine block with an adapter arm and allows us to lean the engine forward and back to slide it right into position. We did have a clearance issue with the tall truck intake on our engine, but by clearancing a small tab on the intake we were able to get the adapter to fit. We recommend removing the front fenders and grille for additional ease of installation.
5 Putting a Chevy V-8 in a Jeep is just about the easiest engine swap known to man. For example, we were able to call Mountain Off-Road Enterprise (M.O.R.E.) and order up bomb-proof motor mounts specifically for a Gen III or IV LS engines in a ’97-’06 TJ frame. First step, clean the framerails for welding.
6 Mountain’s instructions suggest the best position for the engine by measuring off the factory suspension mounts based on years of swapping experience, and luckily we can adjust the body mounts on our project to guarantee firewall to engine clearance. If you are not doing a basic swap like a GM V-8 swap into a Jeep, you need to consider the following: engine to firewall clearance, oil pan to axle clearance at full suspension compression, front accessory drive clearance, top of engine to hood clearance, exhaust routing, front drive-shaft routing and clearance, air filter mounting location, brake booster clearance, steering shaft routing, and radiator to fan clearance.
7 We only tack-welded the motor mounts into position at first. We wanted to install the engine and drivetrain and make sure all the measurements were correct before welding the drivetrain solidly. Note how the driver-side mount is slightly longer, pushing the engine to the passenger side to allow a bit more clearance for the front axle.
8 We installed the engine, triple-checked our measurements, and burned the motor mounts into place. The M.O.R.E. mounts use a simple bolt-on engine plate and polyurethane bushing and bolts to hold the engine in place. this design is easy to duplicate on whatever oddball engine swap you are working on, but for optimal engine control we recommend building the mounts so the bushings are closer to the engine block rather than close to the framerails. M.O.R.E. also offers a variety of different Bomb Proof mounts including universal kits so check their website first.
9 The M.O.R.E. TJ mounts also offer clearance for the suspension arms to come up as the springs compress. This is important if you are building a custom suspension or engine mounts. If possible, it is best to do them both at the same time to determine clearances. You want the engine to sit as low as possible for stability, but also up enough to keep the oil pan from bashing rocks and other trail obstacles. At the same time you don’t want to limit suspension travel because the axle is going to hit the oil pan, so consider suspension movement.
10 if you think getting the engine in your 4x4 is the biggest part of the job, think again. For example, many people swap a transmission at the same time as they swap an engine, and this can require a new transmission mount. We welded on some tabs, bent up a piece of tubing, added more tabs to the frame and tube, and eventually had this simple-looking crossmember with transmission mount. These are the type of custom parts you have to be willing and able to design and fabricate, especially if you are building something oddball like a cummins in a Land cruiser, or a Buick in a Bronco.
11 One benefit of building something normal like a Jeep is the overabundance of aftermarket support. Though our Jeep truck will look wacky in the end, we were able to use an off-the-shelf GenRight aluminum belly skidplate to protect the swapped-in transmission. GenRight also offers an oil pan skidplate for the engine.
12 Getting fuel to the engine is pretty important as well, especially if you want to be able to drive your freshly repowered 4x4. We prefer an in-tank fuel pump if possible, as submerging the pump in the fuel helps keep it cool and extend its life. Later-model Jeep TJs use an in-tank fuel pump that has enough pressure to fuel most OEM-spec V-8s.
GENRIGHT OFF ROAD
HARBOR FREIGHT TOOLS
MAC’S CUSTOM TIE DOWNS
MOUNTAIN OFF-ROAD ENTERPRISE