Questions about 4.6l v8 motor.

thatsnninety5

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So I have a 1998 ford mustang gt. Obviously came stock with the NPI stuff for the motor. I need a motor swap on it and threw in a PI 4.6l motor from an 05’ Lincoln Town Car. What are the differences in these motors other than being NPI and PI?
 

96blak54

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Your in luck with the newer 05 4.6l getting all of the poor engineered flukes that the early pi heads and engines had. Like 4thread sparkplug holes to 9threads and powdered metal timing ring to stamped steel to name a few. Ford pretty much had the flaws lined out around mid03.

Was their some info in particular you looking for?
 

r3dn3ck

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The 03-04 4.6's in the mustang line got very slightly bigger injectors (from 19 to 21lbs IIRC) and the stuff 96blak54 noted but all in all, they're kinda the same picture. At some point (1999 IIRC) they moved the IAT sensor from its own port behind the MAF into the MAF sensor body. 01+ should have the aluminum coolant crossover version of the intake manifold. It's all little stuff that really should not affect you if you're dropping in a donor motor. Swap the intake manifold, burp the cooling system and bolt your stuff onto it. Should be fine. You might want to check the tooth count on the reluctor wheel on the crank. It's been a couple decades but seem I recall there were 2 models of that with different tooth counts, that would matter a good bit but verify that that's a thing before pulling off the front cover. I'm sure the lads will correct anything I screwed up... it has been 20 years since I've done much of any tinkering with 4.6L 2v.
 
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thatsnninety5

thatsnninety5

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Your in luck with the newer 05 4.6l getting all of the poor engineered flukes that the early pi heads and engines had. Like 4thread sparkplug holes to 9threads and powdered metal timing ring to stamped steel to name a few. Ford pretty much had the flaws lined out around mid03.

Was their some info in particular you looking for?
Yes, so in terms of stock tunes on each motor, how timing is set up, the difference in cams, block, heads all that jazz. I currently have that 05 Lincoln Town Car motor in with Ford Racing 21lb/hr fuel injectors, obviously the PI heads and intake, I have a coil pack set up, as well as BBK Shorty Headers paired with a BBK Catted X-pipe and no mufflers. I also have Motorcraft racing suspension and 3.73 gearing in the rear end. A couple other things too just cant think of them right now. But like I said, is there a difference in the internals of the motor?
 

96blak54

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Being an 05 and from a lincoln, you are good with the latest and greatest the modular platform offered for the platform. Pistons were full float wrist pins by the 2000 in all modulars. Its possible the pistons got 1.2mm thick rings from 1.5mm(not 100% sure, but possible). The timing reluctor is definitely stamped steel and way better than the powder metal cracked prone version.

Now one of Ford quality parts for your platform that im not sure about is the timing chain tensioners. I do know for certainty the exploders with modulars came with plastic chain tensioners. These plastic tensioners were a guaranteed to self emplode, destroying an engine. Maybe lwarrior can confirm if plastic or the better cast iron tensioners were used in his lincoln. I dont recall what year his is, but the man is an encyclopedia of knowledge and one of lifes best kept secrets. We here at sn95forums are lucky the man graces us with his presence....But....and maybe you need to investigate what tensioners you have in detail....if your car came plastic tesioners, you need to be swaping them out asap.
 

96blak54

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From what i have discovered and this info is not stone clad, but all 4.6l pi heads are relatively the same, as for the 5.4l pi heads being the same. There are suddle differences between the 4.6l pi head and 5.4l pi head but not enough to separate them into categories.

Camshafts have differences depending on platform. I can tell you the crownvics 4.6l got the least performance cam and was for more torque and the explorer aluminum 4.6l got the better performance oriented cams, with basically same durations but with higher lift valve openings. Mustang and trucks were more widely produced and have the best performance cams with the longest duration and highest valve lift values. Despite what you may hear around other social media sites, there are mutiple pi cam differences and multiple nonpi cam differences. I personally took the time to investigate my 20+ pairs of camshafts by building a cam measuring station and mapping them out. I did not have any cams from a lincoln towncar, so i cannot for certainty say what cam you have and if it fairs well from the other platforms.
 

r3dn3ck

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Check out this thread of what i found mapping stock cams.

https://www.sn95forums.com/threads/npi-pi-cam-specs.7271
Bro, your link is busted. I get a page about a 351W. From what I can tell, I think there's a DB record collision for threadID 7271.

<nerding>
That's neat. See what happens when you take the relational-ness out of the DB and make the app do it? Cascade update/delete can't be reliably implemented in a web app. That's why relational DB's were invented. Someday someone will see the unwisdom of making the app manage the DB and we'll finally once and for all stop it.
</nerding>
 
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thatsnninety5

thatsnninety5

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From what i have discovered and this info is not stone clad, but all 4.6l pi heads are relatively the same, as for the 5.4l pi heads being the same. There are suddle differences between the 4.6l pi head and 5.4l pi head but not enough to separate them into categories.

Camshafts have differences depending on platform. I can tell you the crownvics 4.6l got the least performance cam and was for more torque and the explorer aluminum 4.6l got the better performance oriented cams, with basically same durations but with higher lift valve openings. Mustang and trucks were more widely produced and have the best performance cams with the longest duration and highest valve lift values. Despite what you may hear around other social media sites, there are mutiple pi cam differences and multiple nonpi cam differences. I personally took the time to investigate my 20+ pairs of camshafts by building a cam measuring station and mapping them out. I did not have any cams from a lincoln towncar, so i cannot for certainty say what cam you have and if it fairs well from the other platforms.
So, if I wanted to improve performance with putting better cams in, what would you recommend would go best with the stock internals of my motor that I can push good power and not blow the engine.
For reference this is all done the the motor as it sits in my car currently:
Ford Performance 21lb/hr fuel injectors
Professional Products 70mm throttle body
PI Intake and heads
3in ID cold air intake with K&N filter
BBK Shorty Headers
BBK Catted X-Pipe w/o mufflers

Outside of the motor as car as the actual car:
Ford Racing 3.73 Gearing in the rear end
Motorcraft racing suspension
Nitto NT555 GT tyres (245/45/zr17) Front and rear

Now with all of these things, again what can I add for power (internally) without blowing the motor.
 

96blak54

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If you want to improve power without tuning the car, stay with a stock version camshaft. Mustang pi cams or 5.4l cams will be what you want. With aftermarket cams, the sky is the limit with selections, but will also be dictated by the direction you want to take the car. Almost any aftermarket cam will require the car to be tuned. And then at that point, to maximize tuning costs in one time package, you may as well increase compression some to compliment your camshaft. And then again with the tune your car may require tune regardless due to knock sensors and such programming....i do not know.

Realistically, if this is a daily driver and you dont want to tune the car, source out a set of mustang pi cams and roll with them. Id suggest higher compression pistons but again knock sensors and tuning requirements.

If you want to do more, you really need to consider how much money you are willing to spend just to gain 30-40 more horsepower naturally aspirated. A dyno tune typically costs now around $600-700.

Quick and easy solution for best bang to the buck is supercharger or turbocharger build on the stock engine.....you gonna need a tune too.

This may not be the info you seek. There are others that will fill your brain with info and lead you where you want to go regardless of the damage you do to yourself long as you pay them money. We are always here to answer questions and help out when you need it. Dont hesitate to ask.

Decide 1st what you want from the car. How do you want this car to be.
 

r3dn3ck

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It's a good motor, the modular 2v platform is tough and reliable and but you gotta understand something about them: You can't just flip one part in isolation and call it good and think it's going to not deliver you some surprises. The 2v motor is not a high RPM motor. It's a mid-range compromise engine in every respect. Biasing a 2v toward high RPM operation, even in a properly configured 2v engine, makes nice looking HP numbers on paper but it very often murders the low end torque production because people push the power band too far toward high rpm HP and, by definition, sacrificing low and mid-range torque production thus making the car kind of a dog at more the common operating RPMs associated with street driving. Too much cam and not enough head flow, too much head flow and not enough cam, lower than necessary compression ratios, etc... are all easy ways to leave a ton of performance on the table and end up spending $$$ in places that don't return or support power production.

3.73 gears are the right direction if you're biasing to just slightly higher rpm for your power band, pushing it out 1500rpm higher than stock. As RPM goes up the available pulse width is reduced so you need a bigger injector to be able to deliver the fuel in the available time slice. Ford had/has a habit of providing just enough injector for the factory configuration. More snot needs more fuel. You will want to bump to a slightly fatter injector depending on how fast you want to spin it and a number of other factors. 24-30lb/hr would be where I'd go on that. I started to run out of injector with 30's after 7500rpm in one of my other NA 4v cars. Factory rods and crank are a weakness particularly with rpm's at or over 6500. Factory rods and crank are surprisingly strong but if you want to be zinging to 6500+ rpm I'd replace them with something stronger only because every 2v I've seen self-generate a set of aftermarket rotating assembly inspection ports did it above 6500rpm. That said, not every stock bottom-end 2v I've seen winding out 7000rpm threw a rod or snapped a crank, but they were sure going to sooner than later.

If you want to make power then you're going to get into engine internals. No two ways about it. The factory heads are a limiting factor. So are factory cams. The OEM compression ratio is lower than ideal for a NA car wanting to make bigger power. Slap a Trick Flow top end (heads and intake) and some cams with 20 degrees more duration and a bit more lift, a cobra crank or aftermarket forged crank (kellog), forged I-beam rods, and pistons set up for 11:1 compression along with some 30lb/hr injectors and run it up to 6500 or 7000rpm. Should be a nice performer with your 3.73's but don't get your hopes too high with regard to dyno numbers. Area under the curve is what matters anyway and I'm sure you'll enjoy such a combo.

You really can't do much to these things without doing a tune. That's just how that cookie crumbles.
 
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thatsnninety5

thatsnninety5

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IMG_7879.png
On the header on the bottom. What size is the hardware for the piece that makes the exhaust bolt onto the headers, mine broke and I cannot find spec for the hardware on it.
 

96blak54

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Are you speaking of the passenger side header that has a mating plate that requires a gasket in-between the plates? That exhaust pipe side has the same plate and the pipe is welded to this plate.

I once was into crownvics and used ford shorty headers from a mustang. The driver side was an easy mount together situation but the passenger side had that plate where the gasket sandwiches between head and exhaust pipe. Since the exhaust had to be custom made, i simply machined another plate to be bolted to the header when the exhaust got made up.

I dont know of any sources for the said plate, but if you look around on fb market place for 96-04 exhaust systems, youll probably get what you need and will be able to use most of it. Their might need to be some modifications for it all to work, but youll have most of what you need
 
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thatsnninety5

thatsnninety5

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Are you speaking of the passenger side header that has a mating plate that requires a gasket in-between the plates? That exhaust pipe side has the same plate and the pipe is welded to this plate.

I once was into crownvics and used ford shorty headers from a mustang. The driver side was an easy mount together situation but the passenger side had that plate where the gasket sandwiches between head and exhaust pipe. Since the exhaust had to be custom made, i simply machined another plate to be bolted to the header when the exhaust got made up.

I dont know of any sources for the said plate, but if you look around on fb market place for 96-04 exhaust systems, youll probably get what you need and will be able to use most of it. Their might need to be some modifications for it all to work, but youll have most of what you need
Yes the passenger side. I just need the hardware specs. What size bolt goes into the hole in the headers to hold my exhaust it. It broke off and it is now winter. I cant even run my heat because it just bring exhaust fumes into my car.
 

96blak54

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Most modular shorty headers came with studs on the passenger side. If you manage to get the bolt out just match it up and replace or drill the stud out and use a bolt and nut long enough. Dont forget a new exhaust gasket
 

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