Engine swap dilemma

[paulwilliamson8230]

Hello, new to the forum but have been a reader for a while now. Early this year I bought a 91 town car on marketplace, I had the cash to get a much nicer looking 3rd gen Town Car but have always had an affinity for the bigger, boxier 2nd gen. what better when I found the first year of the 2nd gen and also the first year for the 4.6 for sale with less than 100k on the clock. When I went to look at it it was in pretty good overall condition although the clearcoat was chipped away on most of the car, only one window rolled down and someone had already did the coil spring conversion on the rear deleting the air ride ( with seemingly way too soft of springs) . The car started right up a bit smokey at first but no rough idle and no leaks. Figuring car probably belonged to an old lady who only drove it on Sunday to church hence the low mileage, I forked over the cash and drove it 70 mi back home without issue. The next day however I go out to start the car and it's smoking like crazy and has an idle lope like it's cammed out. Check oil it's a qt low so I figured it's probably valve seals as they are known to be an issue in the early 4.6. I decide to be thorough and end up doing a compression test, all cyl test within spec except for cyl 3 which is at 30 psi ( this is doing a dry compression test with all plugs out and throttle open) . Next I do a wet compression test to rule out stuck valve or head gasket and pressure comes up to about 90 psi. At this point I'm pretty bummed out, thinking I got a low mileage engine I wouldn't have to worry about and could spend time restoring the exterior, now it looks like I have bad rings in cyl 3. As it is now it smokes like crazy chuggs and runs rough so I have it parked. However my brother has a 2002 town car he wrecked into a tree with a perfectly good 2 valve in it, I'm wondering how difficult it would be to swap that motor into my 91 and if anyone has ever attempted such a task. I know a lot of the top end is way different and getting an obd 2 and trying to wire it into an obd 1 sounds like a nightmare but I'm sure it's possible. Maybe even buy a new intake and just put a carb on it and avoid a lot of the computer crap. It would be a nice increase in power with the newer motor and from what I read the old ford aod trans in the 91 should have the same bell housing pattern as the new motor but not sure about the motor mounts matching up or a whole mess of other issues I haven't thought about. I'm a pretty good shade tree mechanic and have done many engine swaps on chevy but I'm worried this may be biteing off a bit more than I can chew. Any advice would be appreciated, should I even attempt this or wld I be better off just buying a rebuild to put in it.

 

[Action]

This is heaven or hell. There is no purgatory. The 1960s are calling and they do not know what a 4.6l is!!!!

Either you are taking the entire power train and electronics from front pulley to the transmission and includes the exhaust system of the 2002 or do not. Just repair what you have.

The Ford Modular engine was never a static design. And the electronics are not the same from year to year nor model to model in the same year!

The version you have is a 4.6l 2V. It came in 4 different HP versions from 1991 to 2011.
The 1991 is a 190 hp was the first and as you have noted is controlled by EEC IV
The 2002 is a 239 hp version is the last and has dual exhaust and is controlled by OBD II
Neither electronic system has anything in common. Making pieces of the two work together is for electrical engineers. And the electronics controls the transmission as well in a total package. New electronics and old transmission will not play well with each other. Either go with one or the other.

Putting a new intake with a carb, I have seen aftermarket parts for this. And in my opinion that is so far off the reservation, you are creating a one of a kind and doing your own engineering, design, fabrication and installation. This means you have to find a nonelectronic transmission as well. (An old C6 might do that as a guess) Then fabricate fuel lines, accelerator linkages. And the ignition system, not sure how that works. If your goals are difficulty and frustration, go down this path and document it. This would be an interesting build. Title the thread Frankenstein Monster.

Any choices you make there is going to be heavy lifting. Personally the 02 transplant fascinates me. For me it would be the full Monte! Electronics, engine, transmission, driveline and rear axle if the ratios are different. And all of the pieces that go with it. Cooling system, AC, everything!!!! However, I do not have Real Estate in a shop to pull that off. Doing it outside would be asking for another bad event.

Action

 

[Norms1stTC]

Buy a rebuild and call it day, so much easier, and cheaper. It's literally a no brainer.

 

[paulwilliamson8230]

Thanks for the replies, I was afraid an endeavor like that would be opening a whole can of worms I wasn't quite ready to deal with. It would be an awesome build to see done and may have even attempted it in my younger days but I just moved and no longer have the shop space or as many tools as I once did, furthermore I'm getting older and it's much more taxing on me than it once was completing large projects. It's mind blowing how many variations there are in the 4.6 platform and can be quite confusing. I cut my teeth on the old small block chevys growing up and those things are like legos just about anything will fit up thru many years. Counting my blessing though my wife works for orileys and I can get a large discount on a remanufactured engine (have an 8.1 chevy 2500 that I replaced the engine in last year, retail was 4,200$ with discount only paid 2,700$) . Just a shame to see that 02 engine sitting going to waste but I always got an eye on market place maybe ill find a 3rd gen with a blown engine for cheap, as if I need anymore projects lol.