Toyota 3RZ 4 Cylinder Engine Swap - More Turtle PowerPosted in How To: Engine on October 1, 2008
Poor Clampy Has Been Parked In The Corner Of my shop for almost two years now with a busted engine, and not only have I been craving some rockcrawling in my own ride, but I've also hated having my favorite 4x4 looking so derelict. The radiator had busted while four-wheeling, and I patched it together before limping the old truck back to town. Unfortunately the patch didn't hold and by the time I made it back I had paid for it with a blown head gasket and a serious knock coming from under the hood.
Clampy's old 22RE four-cylinder engine was a great powerplant for a mini-truck. Though not a powerhouse, it was torquey and reliable, but when mixed with a blown head and a hundred-some thousand miles it was ready for some help. Of course this opened a can of worms when considering options. Should I repair the old engine or replace it with something else? If I replaced it, what would be the best option? I decided against the rebuild since I was ready for a little more power.
The truck is built around a four-cylinder with ultralow gearing, so I decided against more displacement, and with the price of fuel being so high, I liked the economy of a little motor. I also looked at a small Toyota diesel, but parts are rare in the U.S. I also wasn't sure I could make it a legal swap in California, where many of the trails are roads and require proper registration.
In the end I followed a trend where Toyota guys have been taking the slightly larger four-cylinder from a newer 4x4 Tacoma or 4Runner and swapping it into the old Clampster with help from the crew at Marlin Crawler. Owner Marlin Czajkowski is an icon in the 4x4 Toyota scene, where his work with dual transfer cases is legendary. Both he and his son are also running the 3RZ 2.7L Tacoma four-cylinder in their early-'80s mini-trucks with great results. These 16-valve engines have better cylinder-head flow rates than the 22RE, are small enough to fit in the early Toyota engine bays, and have bellhousings that bolt right up to a G or W Toyota transmission, which were found behind most 22R and 22RE early Toyota engines.
Of course many of you wouldn't dare swap in an engine with less displacement gain than a can of beer, but Clampy has always been an underdog. Clampy still may not win a drag race, but like a good turtle it will keep on plugging away.
Tacomas use a few different four-cylinder engines. The two-wheel-drive models use a 2.4L version known as the 2RZ, and though it's still a step up from the 22RE with a stock 142 hp, for all the work you might as well swap in the 3RZ. The 3RZ is found in the '95-and-newer 4x4 Tacomas, 4Runners, and 2WD T-100s, and can be identified by the 3RZ set in the casting of the engine block. A good thing to remember is that 3RZs are only found in newer six-lug Toyotas (even the two-wheel-drive prerunner models), otherwise the four-cylinder is 2RZ. In some states you'll need a 4x4 version to do a legal swap, so we started with one from a 4x4 Tacoma, but the T-100 version is just as good. Also from '95 to '96 the engines use a distributor, then in the '97 they switched to two coil-ignition packs, and then in 2000 they went to four coil packs, no EGR valve, and two catalytic converters. In '06 they came out with variable valve timing. We went with the distributor engine because it is simpler to install, and when we were hunting for possible engines these were more available.
Before we plucked the tired four-banger from under the hood of this off-road powerhouse, we gave it one last run-on the dyno, that is. We took Clampy over to Precision Auto and put it on the rollers to get some preswap figures. These guys specialize in high-horsepower import cars as well as torque monster diesels, but we could tell they were impressed when Clampy came wheezing and coughing into their shop. Yes, those are the tires off our trailer on the rear end; the 39-inch Krawlers wouldn't fit on the roller.
With the new engine in, we figured it was time to crank up Clampy and give it a run. We raced around the shop a few times and the new engine did great. Can you believe we broke the 39-inch Krawlers loose and did a rear-wheel burnout? (See the video on our Web site). Then we went to the dyno shop for some post-surgery numbers. The Precision Auto guys welcomed us back, and once Clampy was outfitted with the baby trailer tires and safely strapped in place, we started spinning the dyno drum.
The results may astound you, so take a seat. Little Clampy devastated the test with a whopping 100 hp! This is up from the lethargic 59 hp it had with the deathbed 22RE. The torque jumped from 82 to 132 lb-ft...that's a 50% increase. Of course, it's easy to beat a dead horse (or dead four-cylinder), but you may recall a few years back we took Clampy to a local garage and did before-and-after dyno runs with an average tune-up. With a healthy high-mileage 22RE we only produced 83 hp and 111 lb-ft and that was without the drivetrain drag of 1-ton axles. Stay tuned and we'll give you some off-road driving impressions of this engine in a future issue and online.