Chevy 4.3L Swap For 4Runner
Question: I am working on a friend's 1992 Toyota 4Runner, with a 3.0L V-6. He also has a 1993 GMC S-15 Jimmy with a 4.3L Vortec. Both are 4x4s with automatic transmissions, and we want to transplant the 4.3 into the 4Runner. What all will I need to do this project? Any help will be appreciated. I need to know what adapters I need, and if you could possibly give me parts numbers and an idea of an amount the total cost could be, that would help too.
Answer: It should be a fairly easy swap, especially since both vehicles have automatics. The easiest way would be to use engine/trans/transfer case combination from the S-15 since it uses the 4L60E, which is the electric-shift version of the 700R4 trans, and the manual shift NP 231 or the electric shift version of the NP 233. However, the problem here is that the GM transfer case has the front driveshaft on the driver's side, and the Toyota case has it coming out on the passenger's side. This means that you're going to have to adapt the GM trans to the Toyota transfer case. Advance Adapters (www.advanceadapters.com) has one under PN 50-3701.
Engine wiring will be the biggest problem, and if you're really good at electrical work, you can use the complete harness from the GM vehicle and adapt the proper ends. Or, you can send the harness out to Jim's Performance (877/465-9569, www.jimsperformance.com) and have them modify it to work with the Toyota. Another way would be to use a stand-alone harness from places like Speedscene (210/787-4467, www.speedscenewiring.com), Painless Wiring (800/423-9696 (www.painlessperformance.com), or Howell Engine Development (www.howellefi.com).
You're going to need a new radiator, motor mounts, a modified oil pan and have to either modify the existing exhaust system or spring for a set of special headers as clearance around the front driveshaft is quite tight. All these are available from Northwest Off Road Specialties (380/676-1200, www.northwestoffroad.com). Clearance under the front differential is a bit on the tight side, which is why you'll need the modified pan. I've heard that if you install an aftermarket lift kit, a Chevy Astro van pan just may provide the needed clearance. New front and rear driveshafts will also be needed. A new fuel pump will be needed, and some people have been able to modify the GM pump to fit with the Toyota tank or use an external pump of the proper pressure.
If you want to keep the A/C, your best bet is to have an A/C shop mate new hose ends onto the original Toyota lines to match the GM compressor. You should be able to use all the gauges by adapting the Toyota sending units to the Chevy block. The Toyota throttle cable will work with a bit of modification to the end. There are lots of little things that I didn't cover that just take some time to figure out, but overall, the swap is quite do-able.
Total cost for the project? Tough to answer. Maybe if you take your time and shop around for the right prices on parts, and you do all the work yourself, it could be done for about $3,000.
Letter Of The Month
Cure For Radius-Arm Frame Flex?
Question: I have a 1993 F-150 4x4 with a 6-inch suspension lift. When I back up, the front end squats down. I looked to see what was causing it, and the radius arms are flexing the frame side-to-side. I am very concerned about this. How do I fix this problem?
Answer: I pretty much knew the answer to this, but just to be on the safe side, I contacted Jim Cole, vice president of Cage Off-Road (www.cageoffroad.com) for his opinion. Jim has like 20-plus years of experience working with Ford suspensions, and I knew that he could, and would, supply me with a complete answer. Here is what Jim had to say:
"While the radius arms can and do flex with the frame, it is typically a very minor amount, and most people never notice this flex. If it is an exaggerated amount of flex in the frame, than there is most likely a crack, or quite possibly missing bolts in a crossmember (such as the transmission crossmember). If the stock radius arms were used with drop brackets for the back of the radius arms to correct caster in the lift, then double-check to see that the drop brackets are in good condition and all fasteners are tight. Some movement is going to be normal, but excessive movement can be stopped by building a crossmember of sorts to tie the driver's-side drop bracket to the passenger side to limit any excessive movement side-to-side. Many of the downsize Ford trucks use these type of radius arm crossmembers in stock configuration.
"A little information on the Twin Beam suspension (Twin Traction Beam for 4x4s, and Twin I-Beam for 4x2s) is that it cycles in an arc side-to-side and front-to-back such that when more load is placed on the coils, i.e., backing up and transitioning more weight to the front end, the top of the tires will kick in at the top, showing a negative camber angle. On the other hand, if the driver hits the gas while going forward and then stops softly, the tires will tend to be kicked outward at the top, showing too much positive camber with the front of the truck sitting higher than normal. Once you know this, you'll be able to walk through parking lots and see how every "beam truck" Ford parked, whether they pulled in or backed into their parking space. The taller the lift, the more pronounced it is, and the softer the coil, the more pronounced the movement. It is just the nature of this suspension style.
"As a side note, if the vehicle sees regular use with weight in the bed, it is a good idea to have it aligned with that weight in place (for example, a lumber rack or a slide-in camper). Many a Ford contractor van or truck has "mysterious" tire wear on the outside of the tire due to good alignments on empty trucks which is altered when the truck is put in service and the front of the truck is raised slightly due to rear weight transfer, slightly throwing off the alignment and wearing the outside of the tire.
"To summarize, if the frame is cracked or missing a crossmember, this will be visible (or can be checked by an alignment or auto body/frame repair facility), but what you describe of the frontend down when backed in is perfectly normal for a Ford Beam suspension."