Vortecd Toy: 4.3L Toyota Pickup - 4-Wheel & Off-Road Magazine

Toyota pickups and 4Runners, especially four-banger-powered solid-axle rigs, have a two-sided, Superman/Clark Kent reputation. If you own one, you already know what we mean. On one hand, the solid-axle Toys are mechanically bulletproof and can be made into awesome trail rigs that leap impossible obstacles in a single gear; on the other hand, they're grossly, almost ridiculously, underpowered.

131 9802 Vortecd Toy 4 3l Toyota Truck Fix front Engine Hoist Shot Photo 34818237

The Toyota V-6 helps the powerless rep somewhat, but the new mills didn't debut until 1988, two years after Toyota switched to IFS. So, if you want both the super suspension and enough power to merge with freeway traffic on the way to the trail, odds are you've considered an engine swap.

This GM 4.3L V-6/TH700-R4 auto-tranny conversion first caught our eye when we were at Hi-Tech Automotive for our recent Holley Digital Pro-Jection installation (see "Digital Fuel Injection," Nov. '97). The overall buildup is a joint project between Rocky Mountain Off Road Specialties and Hi-Tech. Ken Carner and Chad Morse performed the engine swap for Sean Pond, owner of Trophy Time Outfitters in Grand Junction, Colorado. Pond wanted a powerful, reliable rig to get his hunting clients in and out of the most challenging backcountry terrain and still make great time on the highway.

PhotosView Slideshow In the beginning, Sean Pond's '85 Toyota had a carbureted 22R four-cylinder engine like this. It produced 103 hp and 135 lb-ft of torque. The later, fuel-injected four (22R-E) puts out 116 hp at 4,800 rpm and 140 lb-ft of torque at 2,800. Neither mill was deemed sufficient to power the Toy's 33x12.50-15 Super Swampers with 4.88 differential gearing.

In the beginning, Sean Pond's '85 Toyota had a carbureted 22R four-cylinder engine like this. It produced 103 hp and 135 lb-ft of torque. The later, fuel-injected four (22R-E) puts out 116 hp at 4,800 rpm and 140 lb-ft of torque at 2,800. Neither mill was deemed sufficient to power the Toy's 33x12.50-15 Super Swampers with 4.88 differential gearing.

Why go for the GM 4.3L instead of a To-yota V-6? According to Chad Morse, a Toy-to-Toy swap is more complex and expensive. Besides, the 4.3L simply blows away all but the very latest Toy V-6. A '93 Toyota 3.0L EFI V-6 churns out 150 hp at 4,800 rpm and 180 lb-ft of torque at 3,400. The '93 GM 4.3L used here boasts 190 hp at 4,400 and 250 lb-ft at 2,800. Only the new Toy 3.4L comes close (190 hp at 4,800 and 220 lb-ft at 3,600), but the mill came out in 1995, so it's costly and scarce as a swap candidate.

GM's 4.3L V-6 was intro'd in 1985 as a cut-down version of the 350 (5.7L) V-8. Over the years, the engine has been refined and beefed from its original 155 hp at 4,000 and 230 lb-ft at 2,400 (with a four-barrel carb) to the 190-horse, central-port fuel-injected ('93-'96) or sequential multiport-injected ('97-and-up) screamer it is today. A revamp in 1993 added advanced Vortec heads, an internally balanced crankshaft, and other performance enhancements. The mill and spare parts are plentiful and reasonably priced.

Then the 4.3L was removed for a rebuild. The 4.3L/TH700-R4 position in the bay was determined by first attaching the rear tranny mount of the new bolted-together motor/tranny to the original Toy tranny crossmember. Then the motor-mount position was determined when the assembly was adjusted up and down to make room under the Toy's hood for the Vortec's big intake plenums.

As with any EFI conversion, the real skill involves wiring the harness, sensors, and the computer. It's definitely a job best left to experts such as those at Hi-Tech. Here's how the harness arrived with the GM 4.3L and the TH700-R4. According to Morse and Ken Carner, the basic challenge is to make the Vortec's computer think it's still in the original GM donor. When completed, the engine/computer/sensor array is stock GM. Diagnostics and service are the same as on the original donor.

Morse and Carner cut away the original Toy motor mounts completely, then they modified Advance Adapter mounts (shown) to hold the GM 4.3L. Motor-mount position is critical because the Vortec V-6 is a mouthful for the '85 Toy engine bay and because driveline and differential clearance can be problematic, especially in nonlifted or IFS 4x4s.

Retaining the stock Toyota tranny crossmember and transfer case meant that the TH700-R4 needed a new output shaft and T-case adapter plate to accomplish the mating. Both components came from Advance Adapters. And because the stock T-case stayed in its original position, no driveline-length mods were necessary.

Exhaust clearance is a big problem with this swap. The stock GM 4.3L manifolds are too wide in back to fit between the block and the Toyota frame. The solution came from Advance Adapters in the form of headers designed for the 4.3L-into-Toy installation. Hi-Tech snaked the headers in after the engine and tranny were in place. The necessary oxygen sensor was added 12 inches in front of the catalytic c

The GM 4.3L won't work with a Toy V-6 radiator-the inlets and outlets are on the wrong side. By luck, Morse noticed that a '70s Chevy Monza parked outside the Hi-Tech shop had the near-perfect three-core radiator (that's why the guys look so happy here). The radiator in the 231 V-6-powered car with air matched in overall size, and so did its inlets and outlets; Morse just had to fab a lower support. Of course, you could have a custom radiator built to fit.

Morse cautions that there are clearance problems with the 4.3L/TH700-R4 combo. Even with the Rancho 3 1/2-inch lift on this truck, the 4.3L's oil pan had to be dented in to clear the front driveshaft. According to Morse, if your Toy has IFS or isn't lifted, you'll need an aftermarket pan such as one from Advance Adapters which allows for driveshaft and front axlehousing clearance.

The Vortec V-6 left no room for an engine-mounted fan. Carner and Morse selected a Flex-a-lite electric fan which has a super-thin design so it fits in front of the radiator but behind the front grille. It's shown here with the radiator removed. The unit is thermostatically controlled from 160 to 220 degrees with the twist of a screw, or it can be turned on with a manual override switch.

Little things make a big difference. The original 22R engine was fitted with a return valve for heater water; the 4.3L has no such feature, so Hi-Tech added this valve from an '82 Toy. It's driver-controlled by a dash lever.

The stock 22R gas tank was replaced with the 22R-E (for fuel injection) tank shown here. The 60-psi in-tank pump needed for the Vortec system is too big to fit in the carb-style tank. A frame-mounted pump could be substituted, but the 22R-E tank also has baffles designed to keep fuel from sloshing away from the fuel pickup on inclines when you have less than an eighth of a tank of gas. So it's best to use the later tank and swap in the Vortec pump.

Fuel filters and lines must be upgraded to accommodate the Vortec's high fuel pressure and volume. The Toy's stock 1/4-inch lines must be upgraded to 3/8-inch supply and 5/16-inch return lines because the original lines create too much return pressure and can't handle the necessary fuel volume.

To keep the TH700-R4 running cool and smooth, Morse and Carner chose this trick cooler from Specialty Auto-Tech. The 32-inch cooler is tucked under the Toy's rocker panel. Morse says he likes the unit because it's strong, is vibration resistant, and can't plug up and lose efficiency like a front-mounted unit can.

The stock Toy throttle cable is too short to fit the Vortec bracket. The stock GM bracket is retained, but an Advance Adapters universal Toyota throttle cable is shortened to the proper length and a GM cable end is attached. A stock GM throttle-valve (TV) cable controls the TH700-R4's shift points and kick-down. The 700's lockup feature is retained.

The GM computer is tucked out of sight and out of danger under the dash, and the diagnostic plug is mounted under the steering column. From there, the wiring harness is run to the sensors in the engine compartment and down below. All the GM EFI sensor functions are retained. Hi-Tech supplies the plug-in key and instructions that allow you to troubleshoot the system. Or the unit can be set and serviced by any technician with GM diagnostic equipment.

The stock GM harness wires and plugs provide secure, element-resistant connections between the computer and the EFI's sensors. This central-port injection system has just one injector that is connected to the intake ports by six long tubes. Engine vacuum pulls the fuel charge from the central injector to the appropriate cylinder.

Here it is, nearly twice the horsepower and torque, in a tight-fitting but ever-so-trick package. The 4.3L Vortec conversion isn't the simplest of swaps, but it nets as much power as many small-block V-8s we've encountered. When Hi-Tech Automotive and Rocky Mountain Off Road Specialties finish a buildup like this, it's hard to call it a Toy, and words like stealth fighter and pocket rocket don't seem like exaggerations.

Body Chassis Transmission Drivetrain Electrical Engine Suspension Brakes Wheels Tires Tech QA

Vortecd Toy: 4.3L Toyota Pickup - 4-Wheel & Off-Road Magazine

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