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Discussion Starter · #1 ·
Hello Forums!

I've been lurking a while, gathering research for this swap. I have a 1997 Plymouth Grand Voyager, my parents bought it when it was new and I inherited it when my dad passed away 5 years ago.
I've upgraded, rebuilt, and replaced most everything on the van, and the time has come at last for an engine. I currently have the 3.3L V6. My plan is to get a 3.5L or 4.0L long block out of a Pacifica(because it is FWD), swap the externals and electronics from a ~1997 LH Platform car, build a custom wiring harness, and cross my fingers that a 1997 LH PCM will work with my 1997 NS(minivan) BCM and instrument cluster, and the 2000 NS TCM I have in there currently.

There are a lot of 300M's in the junkyards near me, but I think these all have the later PCM with integrated TCM similar to the 2004+ minivans. Not sure if there are heads, camshafts, or intake that would be worth grabbing off of one of these motors.

I'm assuming that all of the 1998+ 2nd gen PCMs are totally incompatible. The 1996/1995 or older 1st gen PCMs probably won't work because they didn't support OBDII.

I know that Dodge crammed a 3.5L into their 1999 Caravan RT Concept, but I don't know how difficult of a process this was.

Came here to get knowledge and insight from y'all, let me know if you have any tips or pointers.



41310
 

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Welcome to the site, I'll say Chrysler's systems are more compatible than most, couldnt begin to tell you what would be involved with yours though; if it was mine, lots of research and trial and error would be involved lol.... as far as LH cars if you stick with the design levels--93-97, 98-01, 02-04, ex it is pretty easy to mix engines and controllers. Sometimes that works across models. Good luck with the swap and post pics if you do it.
 

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My take, I think you are creating a LOT of work and trouble for yourself. That 3.3 can be made into a serious performer if thats what you are after.
 

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Discussion Starter · #5 · (Edited)
Current 3.3L 158hp 203ft/lbs
3rd gen 3.8L 180hp 240ft/lbs
4th gen 3.8L 215hp 245ft/lbs
SOHC 4.0L 253hp 262ft/lbs

I could take a 4th gen 3.8 long block, swap the 3rd gen 3.8 electronics, sensors, and accessories onto it, and probably have a plug and play swap.

The only reason to be shy of the 4.0 or 3.5L is the potential problems with electronics. If I were to try to get SOHC V6 power out of a 3.3 or 3.8L, I would need some sort of piggyback PCM anyways. Even the 4th gen 3.8L long lock might be pushing what my PCM can handle with its different heads and camshaft.

The suspension, brakes, and transmission are already modified into Frankensteins of different years and models of Chryslers, might as well swap a one off engine into it too.


41316




I see the yards near me have a couple 1994-1995 Intrepids, and a bunch of 2nd gen Intrepids and 300m's. Should I harvest anything from the 2nd gens?
I think I'm going to pull the 4.0 motor out of 2010 Caravan I saw totalled, I'm still unsure if I pull the harness, PCM, and engine externals off one of the 1994/1995 Intrepids if this will be suitable? I won't need a 96/97 PCM for OBDII? If I do need a 96/97 PCM, is the 94/95 harness compatible?


100%, I'm pulling a 4.0L from the salvage yard on Saturday. It will either end up working, or the 4.0L motor will end up in the trash...
 

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One of the things you might need to consider is that the control systems for these engines are hardly compatible at all. IIRC, your 1997 SBECII system bears almost no resemblance to the intended 2010 CAN-XX you are eyeballing. This would be a total shot in the dark trying to make your BCM controlled peripherals talk to the CAN bus control system for the engine. Not to mention the inherent differences in bus speed etc.

Maybe you can figure these out... I would consider it a can of worms best left sealed.
 

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Discussion Starter · #7 ·
One of the things you might need to consider is that the control systems for these engines are hardly compatible at all. IIRC, your 1997 SBECII system bears almost no resemblance to the intended 2010 CAN-XX you are eyeballing. This would be a total shot in the dark trying to make your BCM controlled peripherals talk to the CAN bus control system for the engine. Not to mention the inherent differences in bus speed etc.

Maybe you can figure these out... I would consider it a can of worms best left sealed.

This is a 1997 Minivan PCM pinout-
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This is a 1997 LH Platform PCM pinout-
41318


source:
1)
1997 Chrysler NS Platform Service Manual, Property of DaimlerChrysler Corporation
2) 1997 Chrysler LH Platform Service Manual, Property of DaimlerChrysler Corporation






Pretty darn close to identical as far as engine wiring, both are CCD Bus
 

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This is a 1997 Minivan PCM pinout-
This is a 1997 LH Platform PCM pinout-


source:
1)
1997 Chrysler NS Platform Service Manual, Property of DaimlerChrysler Corporation
2) 1997 Chrysler LH Platform Service Manual, Property of DaimlerChrysler Corporation






Pretty darn close to identical as far as engine wiring, both are CCD Bus
Interesting, at a glance, it'd probably run; all the important stuff looks to be the same.

You might have to re-pin a few things such as knock sensor circuit, etc, to get it perfect;

A bit more R&D on the electronics you might be ok;
 

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Aren't the engine block castings for the engine mounts in different places for the Longitude mount engines vs Transverse mount? And other things like Oil filter location, etc different on the mount tyoe engines.
 

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So, what you are after is the OHC of the 4.0L? You are intending to use a 1997 3.5L LH PCM SBEC-II to run a 2010 RS 4.0L? Wow! As mentioned before, that is ambitious! However, differences in the actual flywheel and cam sensors tone wheel construction is probably a major hindrance. It was nearly impossible to run a Can-Bus engine with an SBEC controller. I have no idea what a NGC engine would look like to SBEC. As mentioned before, it might be a task that would require some form of emulation software. My big question would be "Why."
 

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Aren't the engine block castings for the engine mounts in different places for the Longitude mount engines vs Transverse mount? And other things like Oil filter location, etc different on the mount tyoe engines.
Research on that one on the engines he is looking at using. Lots of Chrysler engines were compatible either way by changing brackets etc.

Example; the 2.7 could be used either way. Just had to change the engine mounts, and install a transverse mount front cover. No big deal. All the mounting holes existed in the block for both setups. Pretty cool.
 

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Discussion Starter · #12 ·
Aren't the engine block castings for the engine mounts in different places for the Longitude mount engines vs Transverse mount? And other things like Oil filter location, etc different on the mount tyoe engines.
If I pull a 3.5 or 4.0 block out of a Pacifica or Grand Caravan, I should be gold mechanically. These two had the 3.5 mated to the same transmission I have, they're FWD, they had 3.3/3.8 engines as the base model.

I may have to fab up the front engine mount. I may have to slide the engine forward an inch to clear the firewall, shouldn't be hard if I pour some polyurethane bushings.
 

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2.7L, yes... 3.5L not really. The LX brand of Longitudinal 3.5L was quite a bit different. The 1997 and older 3.5L was a totally different engine IIRC.
 

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Discussion Starter · #14 ·
So, what you are after is the OHC of the 4.0L? You are intending to use a 1997 3.5L LH PCM SBEC-II to run a 2010 RS 4.0L? Wow! As mentioned before, that is ambitious! However, differences in the actual flywheel and cam sensors tone wheel construction is probably a major hindrance. It was nearly impossible to run a Can-Bus engine with an SBEC controller. I have no idea what a NGC engine would look like to SBEC. As mentioned before, it might be a task that would require some form of emulation software. My big question would be "Why."
Yes, the 3.5 or 4.0 out of a FWD would be ideal, that leaves me with 2008-2010 longblocks.

How much I have to swap over, I'm not sure. Maybe I need the intake and sensors off the 1997 Intrepid. Maybe I also need the heads and camshaft. Hopefully the extra 0.5L isn't a problem, I'd like to have the larger displacement if I can obviously.
I am prepared for the possibility and eventuality of needing a piggyback ECU, hopefully I can get it to run ok with the late block and early electronics.
 

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Might have been the LX 3.5 or similar someone intended to use and he found the castings for the mounts totally different and something to do with the Oil filter/cooler location different and interfering. I remember reading about the failed experiment on here. Pretty sure it was going in an LH...not sure if it was 1st or 2nd gen.
 

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I did start that exact project and found those exact differences and several more. It was a severe headache that never saw completion.
 

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2.7L, yes... 3.5L not really. The LX brand of Longitudinal 3.5L was quite a bit different. The 1997 and older 3.5L was a totally different engine IIRC.
Yep, would take some research. The 97 and older 3.5 is very similar to the 98-02 3.5, not sure going newer than that. LX engine could be adapted to a LH, but not sure about transverse setup there.
 

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Special_EDy, take a look at the 2002 and up CS body PCM configuration, (Pacifica) The 3.3L and 3.8L engine controller from 1997 is a different breed. I really don't see it working.
 

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Discussion Starter · #19 · (Edited)
Ok, let me rephrase this.
The most probable, compatible solution-

1997 Intrepid PCM
1997 Intrepid Wiring Harness reconfigured for my application
1997 Intrepid heads, intake manifold, and sensors
2004-2007 Pacifica 3.5L FWD block
Pacifica accessories plumbed to fit my van


I'm going to use a FWD block. The FWD blocks are better anyways, at least the 4.0 has external webbing cast into it and both are capable of mounting to the AWD PTU. 4.0L block has the same bore and journals too, only the crank rods and pistons are different besides the external webbing.

So, the block is a non-issue. FWD 3.5 short blocks are a thing, in fact they are in Pacificas, which also had 3.8L engines that are a direct bolt in to my van. There is even a chance that some combination of front motor mount bolts right up...

The 1997 Intrepid PCM might communicate with my BCM, TCM, and cluster. It looks pretty damn similar. If not, the two engines are close enough that piggybacking an LH Platform PCM onto the NS Platform PCM should be feasible.

The crankshaft position sensor for the 97 LH and my 97 NS are both located inside the transmission housing. They utilize the same exact part number flex plate for crankshaft timing. I'm unsure where the tone wheel for the camshaft is, that might be a key difference between 1st gen and 2nd gen LH engines. I know on our 3.3/3.8, they altered the camshaft tone wheel between the <2003 CCD bus years and <2004 CAN Bus years, swapping this part is essential for us to use an engine from the opposing system.

If possible, it would be better to have the later 3.5 or 4.0 heads and camshafts, as well as the extra displacement of the 4.0L longer stroked crankshaft. More lift, more duration, more power. It might run kind of ok on the 1997 electronics, it might run great, it might run like a turd. If it's ok or a turd, I need a piggyback PCM. Somebody here has certainly seen what happens to a late 3.5 or even 4.0 on a 1st gen PCM?🤷


Everything else is your standard motor swap problems. Plumb the new accessories to fit my system; vacuum system, power steering, AC, coolant, Alternator, fuel, exhaust. Relatively easy stuff next to the electronics. Fabricate the front motor mount(passenger side frame), the casting should be in the block but I may have to get a custom bracket machined.
 

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You'll probably need to figure out how to weld a SBEC cam tone wheel to the NGC cam gear. Same with the flywheel. I think the early 3.5L cams had an adjustable TDC, where the NGC cams had a keyed notch. This made putting an early style cam gear with the tone wheel on the late model NGC or 4.0L cam unlikely.

I'm not familiar with the grinds of the journals on early vs late 3.5L and 4.0L. They might be different too.
 
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