So currently my daily driver is a just-purchased 1999 Voyager (re-badged Caravan) with the I-4 2.4L engine and three-speed 31TH transmission. It's running OK, but when the engine is hot and idling (say, at a stop light) the oil pressure light has a tendency to come on. Makes me think that the bearings are shot. Right now the odometer reads 152800 miles...but, according to Equifax's Car Data, it was showing 274,000 at the time of it's last state safety inspection. Amazing how that happens....

I'm not thrilled with the 2.4L's performance and, since a 3.3L V6 crate motor is actually cheaper than the 2.4, even if I eat the core charge, I'm thinking of going that route. Please note that I have no pretensions of "restoring" or otherwise tricking out this well-worn Plymouth; I just want a reliable daily driver to keep me going for a few more years. But I've never done an engine swap before, although I have pulled and rebuilt a (318) engine...Reagan was president. So I'm wanting to be aware of the ramifications which go along with it, such as cooling, suspension, air conditioning, and so forth.

• The front end needs some work; I'm planning to replace front struts and (probably) ball joints and this currently has a higher priority than the new engine. Is there a difference in struts between the engine sizes, and if so should I purchase parts in anticipation of the engine swap? Also, what other work (brakes, etc.) should I plan on doing while I'm in there?
• One of the reasons I bought this van was that the air conditioning, after all these years, was still good. Can the compressor and related items from a 2.4L be re-used on a 3.3L? Will new mounts and brackets be necessary?
• Do any changes need to be made to the engine computer for emissions purposes? I live in an emissions-regulated county.
• Will the engine cooling system need an upgrade?
• If I'm going to change out the engine, would a transmission upgrade be advisable as well? What's the consensus on the best engine/transmission combo for this vintage of a vehicle?

Thanks in advance for any helpful replies.

 

If you do the swap you need an ECU that matches that engine. You likely need a different transmission bolt pattern too. Perhaps the gearbox is different too. Go to a parts store lookup and see if the drive axles are the same on the V6. If not then you have to look at the hub assembly and so on until you get to the wheel. If even the wheels are different then you are SOL because you might as well buy a used van with the engine you want.

But as you said "There are very few problems which cannot be solved by a suitable application of high explosives."

 

Yes, after taking a look at what all is involved I think that an engine swap is aiming too high...at least for a 20 year old minivan. If I do change the engine it will be with another 2.4 liter, either rebuilt long block or simply a used engine with less miles. Or, I may just change out the timing belt and water pump and see how many more miles I can get from the existing unit.

 

You could also find a lower mileage used engine and give it a good once over before installing it. Obviously everything is easier to access with the engine out, so replacing timing chain and re-sealing leaks (oil pan for example) would be easy to do before the swap.

Just be observant if you go this route - a lot of salvage yards will pull engines for you but that doesn’t mean they’re always careful in doing so. One of our local yards will cut and hack off anything that’s not a bolt or bracket, so hoses, wire looms and the like are typically useless when the engine comes to us. If there’s anything specific you want or need with the replacement engine, tell them specifically what it is so they don’t destroy it on removal.

It would also be an ideal time to deal with any transmission or steering issues if you’ve had any concerns in those areas.