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Explorer Gt-40 to GT40P

Orangeoutlaw

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City, State
Morganton nc
Year, Model & Trim Level
1997 Mercury Mountaineer
I have a early 1997 Explorer with the gt-40 non p Heads , I purchased a gt-40p engine only to find out some emission equipment differences . I live in NC so I have to be able to pass the test both visual and sniffer test . What do I need to do to convert the system over to something I can use and pass emissions with.Any help is appreciated.
 



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the only difference as far as emissions is the P head engine has the EGR tube outside of the intake manifold, that is what you are seeing

P heads: the EGR tube that feeds the EGR system from the exhaust is mounted on the exhaust manifold.

Non P head: On the older non p head engine the EGR feed is done inside the intake manifold.

Both engines are fitted with EGR, so the emissions test is the same, EGR is still present.
 






Ah-
you will also need the gt4op manifolds, with the egr bung. Pre gt 40p manifolds will not work on p heads--spark plug angle issue-

How about the wiring harness and pcm. Will they handle the DPFE sensor input?
 






Jeez .... I knew I should have kept the non p engine..... I was just trying to get every little advantage that the p heads offer.... I wonder if I can take the intake off the my engine and use on the p headed motor
 






yes you can, in fact the intakes are identical up until the throttle body elbow... on the external EGR (P heads) the throttle body elbow just blocks off the EGR passage, on the P head engine the EGR mounts right to theTB elbow

You dont need to swap intakes, just the TB elbow... very simple

HOWEVER I DO NOT THINK the non p head exhaust manifolds fit the P heads... so since you need the manifolds anyways.......
 






Ok good thats good news as I can move forward with the swap. I guess I will need the TM headers for the P-Heads. Then. I am replacing the water pump the oil pump and timing set all the belts and hoses. Its getting Full roller rockers (1.6),comp cams xe258,trick flow valve springs retainers and seals etc. Is there anything I am missing that should be done while engine is still out ? Oh I was gonna ask if the intake spacers are work it ? If so which size ? I am open to any other suggestions anyone has about my project.
 






1" intake spacer yes worth it
delete the hot water bypass for the intake, its just more plumbing to worry about
You will then want to get some sort of CAI and exhaust, I like to delete the secondary cats on the 5.0L and run a dual inlet single outlet muffler, 2.5" -2.75" pipe

After all this tune it (computer) and you are good to go!
 






1" intake spacer yes worth it
delete the hot water bypass for the intake, its just more plumbing to worry about
You will then want to get some sort of CAI and exhaust, I like to delete the secondary cats on the 5.0L and run a dual inlet single outlet muffler, 2.5" -2.75" pipe

After all this tune it (computer) and you are good to go!

soooo whats the intake space thing all about? i tried a search. to no avail
 






The intake manifolds are all different between GT40 and GT40P heads. I would keep the older PCM system and that EGR style. I don't know if the PCM would do fine with the external EGR, I would prefer that I guess myself.

The easiest thing to do is to use your old intake set complete. Use the lower, upper, and the elbow. The lower and upper intake you had have EGR passages in them. The GT40P intake have no EGR passages in them at all. If you used the newer intake you would not have a functioning EGR system. The early elbow runs the EGR flow into the intake, while the later elbow dumps the EGR flow directly into the air flow inside the elbow.

I am using my spare GT40 intake for my 98 engine, for the later EGR style it doesn't matter. Good luck,
 






where in north carolina are you? i'm originaly from the outer banks and they don't do sniffers down there. if your close to hatteras island, or nags head. go over that way to have it done.
 






I live in the foothills near Hickory,found out from my mechanic that they dont do the sniffer test anymore they just see if there are any obd codes in the ecm and a visual
 






wow... all they do in hatteras is have you turn the lights on and hit the horn. and your out the door :p
 






OK I finally rounded up the cash to swap in the p motor to replace the non p . Went and took it to the shop and the guy refuses to do it because of the emmision tubes that go into the back of the heads on a non p do not exist on the p engine. I dont have the facilites to domit my self and everyone around here is is telling me the same thing .... no go . So can I have the heads drilled to accept the emmisions tube ? I need some suggestions guys
 






educate your mechanic about the differences between internal and external EGR as detailed in this thread.

It is ALWAYS emissions LEGAL to convert to a later model engine

both engines HAVE EGR, so there is no difference emissions wise, exept you can physically see the EGR tube on teh p head engine and cannot on teh non p head, that is the ONLY difference, both engines have EGR
just SLIGHTLY different versions.
It was my understanding the only change is in the intake elbow, not in the intakes themselves, but not according to CDW and he knows his stuff!
I vote read this thread a few times, take notes, look at the differences on paper if you can or heck on teh two engines you have, and then educate your mechanic. If he knew the differences he would know this is an emissions legal conversion, even in CA it would be
 






I have a few wrenches to throw in-
will the 97 gt40 PCM recognize the gt40p DPFE sensor? Will the 97 gt40 harness work with the required gt40p sensor connectors?

the external egr has an egr sensor and solenoid-plus the vacuum regulator-

the internal egr has no such sensors-. I'm sure there are other differences?
 






I would:
try to use the P headed engine with my non p head intakes and computer
retain the internal EGR and just plug the EGR bung in the p head manifolds
 






If you use the non p harness, there is no DPFE sensor, there were only 2 sensors on my 96 harness that didn't plug directly into the 98 motor. the TPS and the coolant temp sensor. I didn't have to mess with the TPS because I used a mustang style TB and sensor. The Temp sensor was easily solved by using the 96 style sensor because the holes and threads were the same, 3/8 NPT as I recall.

If he uses the non PI intake and non PI coolant tube assembly: the EGR will not be a problem, the vacuum lines will not be a problem, the coolant lines to the intake will not be a problem.
 






wow... all they do in hatteras is have you turn the lights on and hit the horn. and your out the door :p

Too bad you guys don't live in Michigan- they're so happy that we still live here, they don't even test anything anymore... :D
 






here in CO they dont test anything either, they look with a mirror for a cat converter then they run the sniffer test on the tailpipe, thats it!
Never said a word when I went from 2.9L to 4.0L and then from 4.0L to 5.0L......the 5.0L actually blows better numbers then my old cracked head 2.9L did... so on paper it runs twice as clean even though I have 2 more cylinders and 2.1 more liters of displacement

My conversion would even be legal in CA though....where the emission nazis live

this one shouldnt be too hard to get to pass though, I mean going from a 96 engine to a 98 engine is always a good thing, emissions nazi wise
 



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I'd suggest doing as Jamie and the others mentioned. Keep the OEM vehicle EGR system, the GT40P heads will work great with them. The Explorer V8 EGR system is no longer related to the heads, any head that a header is available for will work.

The GT40P intakes(1997.5-2001) do not have any EGR passages in them. Ford took them out, you can tell by the gap in the center of the lower between the front and rear ports(where the upper meets).

The GT40P uppers also are more likely to break at the front/rear corners. They are not as strong there as before, so the older GT40 intakes are better choices.
 






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