New PI Motor Or rebuilt Non PI

Bramcavender

Bramcavender

Active User
Apr 1, 2009
55
8
18
Barboursville, WV
#1
Hey guys, I'm a newbie by the way. I have a 98GT that I was either considering doing a used PI motor swap, or rebuilding my motor with .30 forged pistons/stock crank/rods and ported Non PI heads, with long tubes and a few other bolt ons. My question is which would run better, which would you do? I'm new to the 4.6 things so I'm not sure whats the best route, thanks for any help
 
#4
After being ported, NPI heads will certainly flow more than a stock PI head, and even more than a ported PI head of the porter is talented. The real shame would be to keep running a NPI intake and NPI cams.

Rebuilding the NPI will be a LOT more expensive than swapping in a PI engine. I assume your NPI is shot? If it doesn't need to be bored over, you can save a LOT of money.

As for what combination would be best... if you are going to stick with a NPI intake and cams, but run ported heads, you'll be very disappointed. However, a stock PI engine won't make that much power too.

In my opinion, the ideal 'budget' combination would be a NPI shortblock with ported PI heads, a lopey cam, PI intake and long tube headers. With the other supporting parts, it should put down more than 300rwhp.
 
#5
No the motor still runs strong, it's got over 100k and is starting to smoke a little. I originally was gonna put on pi heads, but it seems like more work than swapping in a whole pi motor. And than I thought why not just rebuild my npi motor. So I really have no clue which direction to go. i don't think my npi motor needs it but I was gonna go the .30 over route just for some extra cubes(small I Know). that way I knew the bottom end would be a little stronger than stock and add some N20 later. These mod motors aren't like my ol 5.0, so I am sorta lost. Thanks for the replys, keep em coming
 
#6
Bramcavender said:
No the motor still runs strong, it's got over 100k and is starting to smoke a little. I originally was gonna put on pi heads, but it seems like more work than swapping in a whole pi motor. And than I thought why not just rebuild my npi motor. So I really have no clue which direction to go. i don't think my npi motor needs it but I was gonna go the .30 over route just for some extra cubes(small I Know). that way I knew the bottom end would be a little stronger than stock and add some N20 later. These mod motors aren't like my ol 5.0, so I am sorta lost. Thanks for the replys, keep em coming
Click to expand...

Sounds like the valve seals need to be replaced. I wouldn't rebuild the engine if that is the case.

To answer your original question if the engine needs to be rebuilt. I would swap an Explorer 4.6L 2V in. It is a PI engine with an aluminum block so you will knock about 85 pounds off the front end. It is pretty tough to beat this option because of the weight savings and how cheaply you can get an Explorer engine compared to the other options...
 
#8
At this point, for all the trouble you'd go through just to replace your items with the stock crank and rods and having to swap over to a later PI intake anyway to make any power, you're probably better off just swapping in a low mileage PI engine from an '02-'05 Explorer. Same platform as the GT, but with an aluminum block for weight savings.

Its cheaper, with quicker turn around time and far less hassle to perform and in the end you'll end up making the same amount of power. Especially if you port the NPI heads, but stick with the stock NPI cam profiles. And unless you're running nitrous, or some form of forced induction, the forged slugs are overkill. And if you are running some form of power adder, then your rods are going to be replaced as well.

Again....skip the rebuild and swap it outright. Your fuel and ignition components will swap over to the new engine. Your nerves will thank you in the end, especially if you're a newbie to the modular scene.
 
#10
Bramcavender said:
Again thanks, I am really liking the Explorer swap option, seems like the way to go, a lite car is a happy car, right. Anybobdy does this swap, and really happy with it.
Click to expand...

I don't see how one couldn't be happy with it. Anytime you remove weight from the front end, you're improving both handling and the over all balance opf the car. Not to mention more capably transfer weight to the rear wheels in those situations where strait line acceleration is the goal.

For the life of me, I don’t know why Ford chose not to equip all their modular engines with the IL2E block. It’s almost as strong as the standard iron block (by strong I mean capable of well into the 800hp+ range) and not a whole lot more expensive to mass produce. :shrug:
 
#13
I just did this swap. 03 mounty pi engine in. The only thing I ran into was the intake. While it is a pi intake, it doesn't have the heater return on the passenger back. (it is there, but not drilled out for the coolant to dump into). I did not notice this until the motor was in the car and we were hooking up the last of the stuff to start it. So we just ran a hose up to the front to the cross over and t-ed it off with one of the sensors. Works for now, but if I had to do it again, I'd pull the intake and drill out the plastic in the back. Real easy fix, just needed the intake off the motor.

I cannot tell you how good of a difference it is between the npi and pi b/c my npi motor was only hitting on 6 cylinders. But overall, my car feels great.

You have to swap your front cover, cam covers, oil pan and pick up to make this work. Everything else bolts right up. The mounty motors use a 6 bolt flywheel like your 98 does so that. Do yourself a favor and go to oriellys and rent their thread repair kit to clean up all the threads on the block before you go bolting stuff on. We had a few threads that were dirty and needed cleaned before we could get things on correctly. You will also have to swap over your oil filter housing, Pita.... but is needed. Thats all I can think of for now. Well worth the swap to. I pulled my a/c at the same time so i really lightened up the front of the car.
 
#15
Its really a direct bolt in swap. I don't know about your area but here you have to order mod parts ahead of time (gaskets, motor mounts and such) so plan ahead unlike I did. (I'm used to 5.0's that EVERYONE stocks most parts). Take your time. We swaped the crank timing chain sprocket and crank sensor pick up wheel from the 98 motor into the 03 and re timed the cams. I do not believe that is needed though. Make sure you use the 98 front cover AND SENSORS. The 03's will bolt in but are different sensors.

Replace ur motor/trans mounts while your doing this for good measure. Install a set of long tubes if your budget allows, mine did not and I wish it did....

Good luck and keep us posted.
 
#17
I've been looking for a new motor and I keep finding ones from crown vics/mercury and vans that say they are PI motors. Are any aluminum, or will they work for my PI swap, thanks!
And I also found a 03 Mercury Mountaineer 4.6 with 60k for $650. Is that a good deal and the aluminum engine we've been talking about?
 
#18
Bramcavender said:
I've been looking for a new motor and I keep finding ones from crown vics/mercury and vans that say they are PI motors. Are any aluminum, or will they work for my PI swap, thanks!
And I also found a 03 Mercury Mountaineer 4.6 with 60k for $650. Is that a good deal and the aluminum engine we've been talking about?
Click to expand...

No, the only aluminum block 2V PI engine available was in the '02-'05 Explorer/Mountaineer. Check the link I gave you, I did a quick search and found more than half a dozen of them within a couple hundred miles of your area.

...and yes, $650 for an '03 Mountaineer engine with 60K on the clock is a great deal. If it runs, jump on it....fast, before someone else does. The Explorer/Mountaineer swap is very popular amongst the T-Bird/Cougar XR7 guys as well as the '96-'98 Mustang guys....so the engines don't normally sit around long.
 
#20
Look at it this way, even if this one turns out to be bunk and you did have to pay the $125 for shipping from one of the other, you're still ahead of the game. Unless you plan on porting your own heads, you'd sink at least that into a custom port job which basically would cover the cost of an entire used PI engine....and that still doesn't cover the cost of your rebuild, the balancing, PI or better cams, or all the friggin labour you'd have to do to get apart and back together.

Like I said, unless you plan on getting serious with a power adder, you’re wasting your money working with your existing engine. And even still a stock PI engine will take you well into the 375-400rwhp range before you need to start getting nervous.

You're making the right decision by going with the engine swap and saving yourself the headache's :nice:
 
You must log in or register to reply here.

Similar threads

1
Engine Motor swap from a 2003 Explorer
Replies
7
Views
542
SN95 4.6L Mustang Tech
squeak93
squeak93
H
Forced Induction On3 Turbo Kit- Parts list NEEDED - 302 Stock Motor
Replies
21
Views
885
Fox 5.0 Mustang Tech
slow84lx
S
MadSquirrelTech
Engine Suggestions on an engine rebuild. Stock cam/GT40Ps or aftermarket on both for a fun weekend driver?
Replies
23
Views
614
Fox 5.0 Mustang Tech
MadSquirrelTech
MadSquirrelTech
J
Help Figuring Motor Choice(Possible future turbo)?
Replies
13
Views
483
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Jarhead67
J
K
Engine 2000 Mustang GT - Fuel issue post-blown spark plug repair
Replies
4
Views
291
SN95 4.6L Mustang Tech
kenster1092
K
Top Bottom
Back
Forums
Menu