cmerk27

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Apr 26, 2017
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I hope I am posting this in the correct area. I searched for a while on the different engine swap forums and I couldn't find the exact thing I was looking for so I apologize in advance if I missed the correct thread and I am making a duplicate thread. Anyways, I have a manual 1998 Mustang GT with around 192k miles. The engine is giving me all kinds of problems, I feel like I am doing a different repair to it every single day. I'm not exactly sure what is wrong with it this time but I don't care because I want to just swap out the whole motor. I'm pretty sure this is possible but this next part is where I need some help. I have 2 huge salvage yards not too far from me that have 1/2 off motors on Mondays so I want to go up there and get one. I have extremely limited money so I need to do this the cheapest way possible. With the motor discount it will be right around $125 for the entire motor. I am thinking about pulling a 4.6 from a 2001 or newer town car that has the PI 4.6. What I would like to do is just pull the entire engine and auto transmission and swap it directly into my car. My Mustang is having some problems with the tranny so I figured I would swap that too. If that is not possible or if it is way to much work, what would be the easiest way to swap in an engine? I will never be able to find a Mustang 4.6 at one of the yards because they really show up there and are gone almost immediately. If you were in my shoes and had limited money but needed a new motor from the salvage yard, what would you do? Ideally I want to put in another transmission because mine is starting to have problems, and I would love it to be automatic because I have a really bad back and constantly pushing in the clutch is flaring up my back really bad. So if the town car PI swap will work I listed a few questions below so you can kind of get an idea as to what I am thinking. Thank you guys so much in advance!

1. Is getting a PI motor from a Town Car the best choice?

2. If so are there any things to look for in the motor, for example, I want to find a car that had a bad rear impact so that the engine and tranny has been untouched. Is there anything else I should look for when inspecting the engine.

3. What all needs to be changed when putting that engine in my car? I think I heard that I will need to put my old intake manifold on the new engine. I also think I need to put my old timing cover on the new engine so that my distributors can mount on. I think I read that I need to change the valve covers (I don't remember why). I remember hearing something about putting my old heads on the new motor but I am not sure, I would like to keep the new motor not tampered with except for the things that I HAVE to change. Lastly, there was something about maybe having to tap a hole on the aluminum cross member thing up front on the intake manifold where it connects to the thermostat (I know that none of that was technically correct haha)

4. After I swap all of that stuff will the new motor just drop right in and bolt up perfectly?

5. Will the auto tranny bolt right up to the chassis of my car or will it need to be modified? I really hope it will just swaps right in.

6. The last time my clutch was replaced the mechanic said that my exhaust was welded and that they couldn't get to the tranny because they needed a welder and their shop didn't have one so I had to go to another shop that had a welder. Does that mean that it is welded where the headers meet the actual exhaust at the little cross section a little bit behind the engine (Sorry, I know none of that was technically correct)? If so, would I have to get a saw and cut off the exhaust to fit the tranny in there or would it just slide under the car without me having to alter the exhaust?

7. Would I need any special tools? If I have to switch timing covers would I need the crank pulley puller? I know that I will need a quick disconnect tool for some of the hoses.

Thanks a ton in advance guys. I just really need a working car right now and this is the best option I could come up with.
 
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squeak93

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Jun 2, 2005
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Yes a 01 crown vic motor will fit. yes you want to swap your front cover, accessories and cam covers over. yes it will bolt right up. Yes you will need all those tools you described but a great selection of sockets and wrenches/etc.

The auto swap is a bit more detailed. You'll need the correct pedals, wiring harness and the ability for your computer to shift the trans.

As far as the exhaust it does sound like they've welded at least the catback to the midpipe. I'd be very surprised if they welded the mid pipe to the headers due to the amount of working space but I've seen dumber stuff before.

Good luck.
 

cmerk27

Active User
Apr 26, 2017
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How could I get the trans to work? If I decide to keep my manual tranny (it will still last, the syncros are screwed though) would the crown vic engine bolt right up to it or would it be different since it's a PI motor?
 

wmburns

SN Certified Technician
Aug 14, 2009
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Ford did a re-work of the electrical systems in 1999. Therefore electrically a 1996-1998 is very different than a 1999-2004 model year. One of the differences is the change from a VSS to OSS speed sensor. So anytime a transmission is swapped across this model year boundary EXPECT problems getting the speedometer to work. This is not a "plug and play" swap.

Further the 4R70W is a PCM controlled transmission. So a suitable automatic PCM would be needed. So IF looking for a "plug and play" manual to automatic swap, you will need:
  • a 1998 automatic PCM
  • a 1998 modular style automatic transmission with a VSS sensor. Yes this will bolt up to any PI or non-PI modular motor.
  • Pedals, harness, drive shaft, flex plate and other items mentioned by squeak93
If the goal of this project is to save $$, then the cost of swapping transmission far outweighs the cost of repairing.

As for the exhaust problem. It's seems to me that this is a good excuse to get a new exhaust system. A cut off saw should make short work of the problem.

Something that you should consider. Remember that the motor swap reuses almost all of the original cars wiring harness, ignition, and most sensors. Any of the current "issues" that you have are sensor or electrically related, EXPECT those same "issues" to remain after the swap. IMO a motor swap should be done to solve problems with the base motor's mechanical condition.
 
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cmerk27

Active User
Apr 26, 2017
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Okay so it sounds like the tranny is wayyyy too much work so I will just keep my current trans. So will the PI motor mount right up to my manual 98 trans? That's what I'm confused about. I'll probably look into how to replace the syncros in the future.
 

cmerk27

Active User
Apr 26, 2017
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Okay so it sounds like the tranny is wayyyy too much work so I will just keep my current trans. So will the PI motor mount right up to my manual 98 trans? That's what I'm confused about. I'll probably look into how to replace the syncros in the future. Also, does it matter which PI motor I get? For example, an F-150, a crown Vic, town car, or will they all do the same thing once they are hooked up to my wiring harness?
 

wmburns

SN Certified Technician
Aug 14, 2009
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So will the PI motor mount right up to my manual 98 trans? That's what I'm confused about.
How many different ways to say, "any modular motor will BOLT up to ANY modular transmission"? Yes it will bolt up.

What won't bolt up is any combination involving OHV V6 (transmission or motor).
Also, does it matter which PI motor I get? For example, an F-150, a crown Vic, town car, or will they all do the same thing once they are hooked up to my wiring harness?
Yes and no. IF you were to pick a car/truck with a Windsor motor this would create flywheel/flexplate issues regarding the number of bolt holes.

Further IF you were to pick a truck motor the intake manifold is taller and won't interchange with the Mustang (hood won't close among other things). For the least amount of trouble pick a Romeo from a Car.

The Town Car, Crown Vic, and Grand Marquis are from the Ford Panther model line. All Panthers use the SAME motor (in the same model year).