Try using a fan off a crown vic. Cheap and effective. They move a lot of air and are usually readily available for cheap at junkyards.i put an electric and a 4 core rad in my 88 3.9 i changed the fan 3 times and it still gets to hot with the ac on in stop and go traffic let me know if it works i nput a hayden on and it wasn't much better than the cheap one. So i'm going dual fan with custom shroud when i put the magnum in it .
1994 Dakota 3.9 to 5.2 swap questions
I've recently become the new owner of a '94 Dakota. 3.9 V6 M/T 4x4. For a truck that's approaching 30 years old, it's in great shape! However, it has 230k+ miles on the original 3.9 V6, and I'm seeing some leaks and hearing some noises that hint at an engine rebuild in the future.
Or... after doing a bit of research, it looks like the 5.2 V8 is a pretty easy swap! I have several other projects, so this will probably be a gradual "grab parts as they turn up" process, not a sprint to completion. However, I wanted to run through what I (think I) know now, and maybe get some feedback from folks to help plan this out.
1. 5.2 engine. We have a few decent yards nearby and I can get a running engine from a wrecked truck for pretty cheap. Ideally I'd just freshen up the top end. It looks like anything from 92-96 will work? Since the 3.9 and 5.2 are very similar blocks, can I retain all my accessories and accessory brackets from the 3.9?
2. ECM from a 5.2 M/T 4x4 truck (PN 56028263). I've seen a few of these remanufactured for about $300. I'm comfortable re-pinning my harness for the two additional injectors (I've built a few harnesses from scratch). I have a 1994 FSM on the way for wiring diagrams.
3. Exhaust. I'll probably pick up a set of factory manifolds with the engine. I can fabricate the rest of the exhaust myself. Will probably do a y-pipe, cat, muffler, and single exit - as close to factory as possible (also means I can use the same hangers).
4. Front suspension. Here's where my lack of knowledge about torsion bar setups shows. I know on a truck with front springs I'd need heavier springs for the extra weight of the V8. Do I need to swap parts with a torsion bar setup, or just adjust the bars?
5. Electric fan, radiator, and shroud modification (or removal). I think an efan is the way to go (makes for better throttle response). I believe I'll need a radiator from a V8 truck (but please correct me if I'm wrong). Also, I'm pretty sure the V6 radiator shroud won't work without modification, but I can figure that out.
I know some folks might chime in with suggestions for more power (cam, 1.7 rockers, dual exhaust with headers, etc etc) but I'm planning to retain the original transmission (which should be the AX15). I'm not trying to put down huge power numbers or hit the strip/track, so the AX15 will do fine behind the 5.2. I like wrenching, and I figured for a bit of extra time and money I could have a neat project AND a more capable truck.
Thanks in advance for any feedback or info!
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Or... after doing a bit of research, it looks like the 5.2 V8 is a pretty easy swap! I have several other projects, so this will probably be a gradual "grab parts as they turn up" process, not a sprint to completion. However, I wanted to run through what I (think I) know now, and maybe get some feedback from folks to help plan this out.
1. 5.2 engine. We have a few decent yards nearby and I can get a running engine from a wrecked truck for pretty cheap. Ideally I'd just freshen up the top end. It looks like anything from 92-96 will work? Since the 3.9 and 5.2 are very similar blocks, can I retain all my accessories and accessory brackets from the 3.9?
2. ECM from a 5.2 M/T 4x4 truck (PN 56028263). I've seen a few of these remanufactured for about $300. I'm comfortable re-pinning my harness for the two additional injectors (I've built a few harnesses from scratch). I have a 1994 FSM on the way for wiring diagrams.
3. Exhaust. I'll probably pick up a set of factory manifolds with the engine. I can fabricate the rest of the exhaust myself. Will probably do a y-pipe, cat, muffler, and single exit - as close to factory as possible (also means I can use the same hangers).
4. Front suspension. Here's where my lack of knowledge about torsion bar setups shows. I know on a truck with front springs I'd need heavier springs for the extra weight of the V8. Do I need to swap parts with a torsion bar setup, or just adjust the bars?
5. Electric fan, radiator, and shroud modification (or removal). I think an efan is the way to go (makes for better throttle response). I believe I'll need a radiator from a V8 truck (but please correct me if I'm wrong). Also, I'm pretty sure the V6 radiator shroud won't work without modification, but I can figure that out.
I know some folks might chime in with suggestions for more power (cam, 1.7 rockers, dual exhaust with headers, etc etc) but I'm planning to retain the original transmission (which should be the AX15). I'm not trying to put down huge power numbers or hit the strip/track, so the AX15 will do fine behind the 5.2. I like wrenching, and I figured for a bit of extra time and money I could have a neat project AND a more capable truck.
Thanks in advance for any feedback or info!
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Unfortunately I don't have an extra bellhousing, I'm sticking with the AX15 that came in my 94 so I'll need that bellhousing for my build. The AX15 should hold up to the 5.2 (I'm not doing any racing or offroading, more of a trash and slash truck) but if it ever fails I'll swap in a NV3500 and I'll save that bellhousing for you.
How big was your fan? I'm going with a 16" that should move over 2200cfm, 2000cfm seems to be the recommended threshold for a stock 5.2 so I think that would be fine. I'm surprised you had overheating issues with an efan on the 3.9, unless it was a much smaller or worse-flowing fan?i put an electric and a 4 core rad in my 88 3.9 i changed the fan 3 times and it still gets to hot with the ac on in stop and go traffic let me know if it works i nput a hayden on and it wasn't much better than the cheap one. So i'm going dual fan with custom shroud when i put the magnum in it .
I have an old data logger I may adapt and put on the truck before and after the swap to track temps, I'll let you know if I do that. That would give me concrete info on how well the electric fan worlks. I'll try logging:
1. 3.9 with clutch fan
2. 3.9 with efan
3. 5.2 with efan
That's fantastic mileage! I can relate on my truck, everyone in the house thinks it's cool but nobody wants to be seen in it haha. I'm only getting about 18 in my 94 with the 3.9 right now, but all my driving is short trips around town.
If you want to send those parts my way I could definitely use the harness, that would probably be just as fast as repinning my existing harness and then I could swap back to the 3.9 easily if needed. I just picked up a PCM but I have no way to test it until I get the swap done, so an extra would also be handy for testing. Shoot me a DM and we can work something out!
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