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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
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Discussion Starter · #21 ·
Still waiting to get the engine block back from the machine shop AGAIN? I remember you posting that they painted it and got overspray inside of it, so you took it back to be re-cleaned/hot tanked. How did they handle that?
They hot tanked it again no charge. I have the block back, but its just sitting in a plastic bag in my truck.
 

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3rd gen > all others
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Seriously considering trying this swap now. My U-Pull yard is having a 40% off driveline sale this week (engine, transmission, axles and drive/CV shafts) and I also have the week off of work so it makes for a perfect opportunity. The 3.5 exhaust manifolds should fit the 4.0 so the exhaust is figured out. I already got a front manifold from a Pacifica with a 3.5. That (3.5 Pacifica engine) seems to be the one to pull everything from to make a 4.0 work in an awd van. It has holes in the block for the transfer case brackets, is mated to a 41TE transmission, and uses a cable-actuated throttle body. It is still run from an NGC PCM, so should communicate the same as the van and fit onto the 4.0. Since I also want to do a front crossmember/drivetrain drop of an inch, that should give me the needed room to play with.

I'm still trying to figure out the electronic side of things. I've compared pinouts of the van NGC PCM and the Pacifica PCM and they are very similar. Only differences are usually blank spaces in the van PCM, that are used for the extra things for the 3.5 PCM like 3 extra ignition coil outputs for coil-on-plug. It would be fun to try a 3.5 PCM with autostick in my 2004 van with the 3.8 first, but the trick is to either find a PCM without security, or find one intact in the yard with the keys in it to take the keys, sentry module, and PCM from. I might be able to widen my search if I knew the Stratus and Intrepids 2.7 computers would also work, or even the 3.5 computers in them. Once again I would need the keys and module to make it work together. I've read the Intrepid guys can run their 3.5 swaps on the 2.7 computers with no problems. The 2.7 was the basic engine, so may be easier to find without security (but no autostick unfortunately).

Has anyone tried a PCM swap across to different platforms like this and it worked? Or read about it somewhere?
 

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3rd gen > all others
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I couldn't resist. I pulled a 4.0 from a 2007 awd Pacifica today. The oil change sticker was dated 2019 and had 139,000 miles on it then, so I figure it probably had 150,000 now. The other 3 4.0's in the yard had over 200,000 miles on them and this Pacifica already had the front crossmember dropped. Got it and pulled it over to a 2005 Pacifica to swap some parts around from a 3.5.

I had to swap the intake plenum/throttle body, EGR pipe, valve covers and coils, and engine wiring harness. Then I found out the 4.0 lower intake manifold is lower than the 3.5, so when I stuck the 3.5 plenum on top it wouldn't even touch! Apparently the fuel rail and injectors might be different too, but the 3.5 harness still plugs into the injectors. Might just make a spacer and get longer bolts to make it fit. It also fouls on the power steering fluid reservoir, and that's how I found out the front timing case is different. The cam sensor is different, and won't plug in. I know it's because of the different computers (3.5 used NGC CAN BUS, 4.0 uses NGC CCD BUS) <-did I get that right, or is it switched around? Anyway, I might be able to find and make a different cam sensor fit/work, but it will also need to be timed right with the windows on the front cam gear (which will be off). So either I try to make all this stuff work by modifying parts, or I will have to get the whole front of a 3.5 Pacifica engine.

I chose the 3.5 parts because they are already NGC for my generation of van (2004), the computer has the correct outputs to control the intake valve tuning in the plenum, and they have autostick (which the vans for some reason don't have 2004-2007). Now I just need to find a Pacifica with the 3.5 and keys in it in the yard.

The engine itself will need some external freshening up with seals, gaskets and belts. At least the oil pan wasn't punched through like all the steel ones are! For now it will probably sit around. Once I get a computer and keys for it, I can spend more money on getting the engine refreshed (new water pump and belt tensioner), get an alternator, power steering lines (they cut all the ones in the junkyard), etc. So the engine, A/C compressor, P/S pump and 62TE torque converter (couldn't get it off, had to pull with engine) came to $220 without the 30 day warranty. That was with the 40% off sale price. (y) Normally just the engine is $228, so I had to take advantage of this. Since my particularly equipped van is heavier than a 5th gen, a 5th gen powerplant should move it along nicely. 😁
 

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3rd Gen Plebeian
1997 Plymouth Grand Voyager Rallye
Joined
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1,058 Posts
Discussion Starter · #24 ·
I couldn't resist. I pulled a 4.0 from a 2007 awd Pacifica today. The oil change sticker was dated 2019 and had 139,000 miles on it then, so I figure it probably had 150,000 now. The other 3 4.0's in the yard had over 200,000 miles on them and this Pacifica already had the front crossmember dropped. Got it and pulled it over to a 2005 Pacifica to swap some parts around from a 3.5.

I had to swap the intake plenum/throttle body, EGR pipe, valve covers and coils, and engine wiring harness. Then I found out the 4.0 lower intake manifold is lower than the 3.5, so when I stuck the 3.5 plenum on top it wouldn't even touch! Apparently the fuel rail and injectors might be different too, but the 3.5 harness still plugs into the injectors. Might just make a spacer and get longer bolts to make it fit. It also fouls on the power steering fluid reservoir, and that's how I found out the front timing case is different. The cam sensor is different, and won't plug in. I know it's because of the different computers (3.5 used NGC CAN BUS, 4.0 uses NGC CCD BUS) <-did I get that right, or is it switched around? Anyway, I might be able to find and make a different cam sensor fit/work, but it will also need to be timed right with the windows on the front cam gear (which will be off). So either I try to make all this stuff work by modifying parts, or I will have to get the whole front of a 3.5 Pacifica engine.

I chose the 3.5 parts because they are already NGC for my generation of van (2004), the computer has the correct outputs to control the intake valve tuning in the plenum, and they have autostick (which the vans for some reason don't have 2004-2007). Now I just need to find a Pacifica with the 3.5 and keys in it in the yard.

The engine itself will need some external freshening up with seals, gaskets and belts. At least the oil pan wasn't punched through like all the steel ones are! For now it will probably sit around. Once I get a computer and keys for it, I can spend more money on getting the engine refreshed (new water pump and belt tensioner), get an alternator, power steering lines (they cut all the ones in the junkyard), etc. So the engine, A/C compressor, P/S pump and 62TE torque converter (couldn't get it off, had to pull with engine) came to $220 without the 30 day warranty. That was with the 40% off sale price. (y) Normally just the engine is $228, so I had to take advantage of this. Since my particularly equipped van is heavier than a 5th gen, a 5th gen powerplant should move it along nicely. 😁
The good news: All SBEC V6's use the same timing, and all NGC V6's use the same timing.

There are only 3 flexplates on Chrysler V6s from the 3.3, 3.8, 2.7, 3.5, and 4.0L engines. Early SBEC, late SBEC(reshaped a torque converter bolt hole), and NGC Flexplates. All are the same size, same ring count, SBEC has three groups of four timing windows, and NGC has maybe 22 windows(?) With a long hole and a skipped hole.
All NGC use the same camshaft timing, likewise with early and late SBEC.
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Theoretically, a 2004 or newer 3.5L or 4.0L is compatible with the 3.8L computer on your minivan, if you can plug it in with the correct sensors. The ignition timing is probably tuned slightly more retarded on the 24Valve SOHC 4.0 than a 12V OHV, but that's what knock sensors or higher octane fuel are for. I plan on attaching the 4.0L with an SBEC(1997) camshaft sprocket and flexplate to my OEM 1997 minivan PCM, it should see it as a perfectly healthy 3.3L. Then I'll just piggyback the aftermarket ECU on to ratchet up the performance, but I'm a bit tempted to see how well the stock computer could run it if I gave it actual control over fuel and ignition...
 
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3rd gen > all others
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Ran out of parts at work and had the day off, so made a drive down to the other U-Pull junkyard (1 1/2 hrs away) to check out their Pacificas. They had 8 of them, all with 3.5's and two had keys in them! So I finally got the NGC computer, key, and ignition switch with sentry module from a 2005 with not even 100,000 miles on it for $45. Yay, another piece of the puzzle collected! They also had one with the steering rack removed, which would have been great to pull the rear exhaust manifold, crossover pipe and downpipe from but I was out of time. Hopefully I can get that another day. Still need an alternator, belt, and power steering pressure line.

Edit 7/23 I have the rest of the week off, so went back to the junkyard today for the other parts. Got the alternator with 100,000 miles, the power steering lines from a 3.5 with the finned fluid cooler, a newer Dayco timing belt, the tensioner pulley and the front head timing sprocket with the correct NGC window pattern. Then I went after the rear exhaust, but it got me first! I had two bolts left, and reached around the cut off stub where they use a hydraulic shear to cut off the catalytic converter and accidentally sliced the inside of my right wrist/forearm about 3 inches. Ouch! I was able to wrap it with a napkin and some tape and finish getting the exhaust off. Got an extra early Explorer wheel for a full size matching winter spare.

Got home, cleaned up, and unwrapped my wound to clean it. Almost passed out it hurt so bad. Got it bandaged up, even though my wife said I should probably get stitches. We'll see how it heals. I had thought about unbolting that sharp stub and removing it first, but figured that would be a waste of time since I was getting the whole works anyway. It would have taken some time, but at least I wouldn't have gotten hurt. Moral: it is better to take a few extra minutes to work smart and safe, than to be focused on efficiency.
 
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