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Discussion Starter #1
Hi.

At the expense of being bombarded with a Normandy-assault-size volume of verbal barrages...I have a couple of questions concerning...yes, the often-idolized, yet often-ridiculed DOHC swap.

And yes, I have perused the 'Search' function on numerous occasions...I've spent quite a bit of time looking in there, but have not really found what it is I'm looking for, so here I am.

I now own a '97 4.6 car. I also now own (for very little cash), a low-mile T45 5-speed out of a Cobra, and a 1994 Lincoln MK8 parts car, which includes a 108K-mile DOHC motor.

Thrown casually into this mix is my original 1992 5.0 car, which I'm really contemplating paying a group of gang members to break into my house, do a bunch of quasi-believable yelling and threatening, and have them steal this car, just so I can have an excuse to go look for something else that's more suitable for a DOHC swap...

Now that this is all out of the way, I'd like to hang onto the '92 5.0 car, and swap in the DOHC/5-speed combo (somewhat like Racecougar and his '90 Cougar), and just keep the '97 4.6 car as a relatively-untouched daily driver.

However, if I am going to have to completely rewire the '92 5.0 car with what sounds like either a 1996 or 1997 4.6 engine and related harness (which I don't have, and i'm not interested in using the MK8 wiring), I'll be honest with you, I'm not really up for this sort of thing, especially if I have to first clear out the existing 5.0 wiring, and attempt to splice it into the car. There are also some aftermarket stand-alone harnesses (or at least they look like a stand-alone), but once again, I'm looking at something of an investment vs. return, in that is this sort of thing even worth it?

....which brings me to the current DOHC swap searches; as it's been mentioned, ad-nauseam, that idiots first utilize the 'search' function here, and in this case, I have looked, and while there are countless mentions of these mythical DOHC swaps being performed, unless I skipped over something, and more than likely I did, all that really ever shows up are the occasional 'update' picture, and "ask so-and-so about what he did on his."

1. Is there a fairly-detailed swap thread out there, concerning the MK8 swap, either to a 1996-1997 4.6 car, or more-detailed version of Racecougar's work, where a 4.6 was swapped into an older Bird?

2. Unless I add a blower/turbo/whatever to the MK8 engine, is this powerplant monstrosity (in N/A form) really worth the effort? I'm recalling seat time spent in a customer's 1996 Cobra that I did a lot of work with, and it was a blast to drive. I wouldn't mind duplicating this car in MN12 form, as the MN12 has much better suspension than the covered-wagon Mustang platforms thoughout the years.

Any thoughts about this one?

3. Is it possible that the 4.6 DOHC and 5-speed would be a better idea for the 1997 4.6 car that I'm currently daily-driving now?

4. Sell the '92 and buy another 1996-1997 4.6 car? I'd like a Cougar this time.

As usual, any comments would be appreciated, and hey, it's not like we're doing anything else anyway, lol.
 

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1. Is there a fairly-detailed swap thread out there, concerning the MK8 swap, either to a 1996-1997 4.6 car, or more-detailed version of Racecougar's work, where a 4.6 was swapped into an older Bird?

2. Unless I add a blower/turbo/whatever to the MK8 engine, is this powerplant monstrosity (in N/A form) really worth the effort? I'm recalling seat time spent in a customer's 1996 Cobra that I did a lot of work with, and it was a blast to drive. I wouldn't mind duplicating this car in MN12 form, as the MN12 has much better suspension than the covered-wagon Mustang platforms thoughout the years.

Any thoughts about this one?

3. Is it possible that the 4.6 DOHC and 5-speed would be a better idea for the 1997 4.6 car that I'm currently daily-driving now?

4. Sell the '92 and buy another 1996-1997 4.6 car? I'd like a Cougar this time.

As usual, any comments would be appreciated, and hey, it's not like we're doing anything else anyway, lol.
1. "Is there a....", no. There is no one single all inclusive thread. You have to piece everything together from all the different threads.

2. Worth the effort? Lets just assume you're going to get tuned since you already know that the timing tables in the MN12 4.6 EEC are completely wrong for a DOHC engine----that said, you'll likely put down about 250 rwhp on 87, and maybe around 260rwhp on 93 octane BUT through a 5-sp trans. Use any auto, and drop-10-15rwhp from those figures. You tell us if it is worth.....

3. For the complexity involved in either donor car, you'd be better off with a PI engine IMO. I get the vibe that you don't want to deal with "nitty gritty details" or "hassles". The DOHC alone (let alone the 5-sp trans) is 120% full of those two things.

4. Getting a 4.6 96/97 MN12 would simplify A LOT of things if you're serious about this.

Besides you'd have to do a heck of a lot more to "match" the feel of that Cobra with the DOHC. It likely had gears, and with the lighter weight, well it's just like more torque multiplication.
 

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My answers would very closely resemble those already posted by GM. It can certainly be done in your '92 5.0L car, but it's a heck of a lot of work. It would be MUCH easier to start with a 4.6L MN12.
 

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2. Worth the effort? Lets just assume you're going to get tuned since you already know that the timing tables in the MN12 4.6 EEC are completely wrong for a DOHC engine----that said, you'll likely put down about 250 rwhp on 87, and maybe around 260rwhp on 93 octane BUT through a 5-sp trans. Use any auto, and drop-10-15rwhp from those figures.
Idk about 235 rwhp then again I'll be making two more runs on the mustang at work soon. With my mods through my built auto what you see in my sig is all I could squeeze out of it (with a conservative tune) heat soaked, but my next couple of runs are going to set new "base line" numbers for work soon to come. I'll be running an unloaded pull on the mustang dyno to simulate dynajet numbers, and get weather corrected SAE numbers now that we have a new weather station add on.

I'll also be the first to try out our new built in Wideband AFR since I have tuned out rear o2's, it will be interesting to compare "professional lab quality" to my Zeitronix setup.

Back to the OP, good luck I can't decide for you, but I enjoy my DOHC swap everyday. I would swap to stick (TR-6060) but with my bad left foot/handicap I can't push the clutch, maybe someday I'll do a hand lever hydraulic clutch and/or dual clutch plate setup. Time will tell.
 

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The Parts Guy
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It's been years, but I think mine put down 243rwhp/246rwtq when it was a stock NA, stock 4R70W, 4.10:1 arrangement.
 

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EvilMooseofDoom said:
Is there a fairly-detailed swap thread out there, concerning the MK8 swap, either to a 1996-1997 4.6 car, or more-detailed version of Racecougar's work, where a 4.6 was swapped into an older Bird?

SCTBird1994 has a really nice build thread over on SCCoA--->>My Latest Project..

He's using the 4.6L DOHC & 4R70W from a Mark VIII in his 1991 Thunderbird..

I don't know if it goes into detail enough for you, but it's definitely worth checking out..



Rayo..
 

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It's been years, but I think mine put down 243rwhp/246rwtq when it was a stock NA, stock 4R70W, 4.10:1 arrangement.
Pretty much inline with what I was linking ±10%. That was on 93 octane?
 

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Discussion Starter #8 (Edited)
I don't know if it goes into detail enough for you, but it's definitely worth checking out..

Rayo..
I'm not trying to have a complaint moment, even though I make complaining a higher art form...I guess with the amount of swaps I've seen over the years, and all the other work/swaps/tech/etc that I've gone through on message board after message board, I guess I'm still a bit shocked to see that people will to to the trouble of telling other people about their exploits...but do it in such a manner that often does not help anyone else who might be wishing to duplicate the first person's efforts.

"I did such and such swap! It was a difficult task, aye, and many dubloons were spent, many a tear was shed, and many a wife were divorced, but I've done it, and I've done it in such a way that it will actually be more confusing to anyone else following my work as compared to if I had never done it at all! Arrgghh! Pieces of Eight!!"

Anyway, you get my point.

Beyond that, I thank all of you for participating. I find myself with a fresh new pile of parts that could be turned into something good and fun to drive, but only if I can separate the time away from my job, my wife and kids, and my horrific writing career to put something together.


http://www.sccoa.com/forums/showthread.php?t=110455&highlight=latest+project

I'm looking at that right now. Am I correct in suggesting that in the first picture or two, that the passenger-side harness which runs over that side shock tower is the main lead from the ECM?

This thread is enlightening, but once again goes back to what I'm saying: There are extreme 'before and after' shots, where major steps have been done, and the photos skip 8 or 9 steps. Argh. Oh yeah...and he never finished the car. Curses.


So far as question #3 and #4 are concerned, I already own a '97 4.6 car, so a proposed DOHC swap would be much easier. I know we're all batting around what might appear to be ridiculously-low RWHP numbers, but I've got quite a bit of seat time in a few different 1996-1997 Cobras, and with just a few mods, they're almost a bit too quick for daily-driver/street duty anyway. I'd like to build my own version of that model of Cobra, but with increased interior and trunk room, not to mention a more-comfortable ride, especially around the misery that makes up the streets around my town.

I'd like to do something fun with my mom's old '92, but unless I wish to spend a small fortune building a pushrod Windsor, installing a heavy 460, or just biting the bullet and tossing a SBC in there, there's not really any reason for my hanging onto the car. I'd like to see if it might be possible to do a 4.6 swap, but not to the point where I've got the entire front half of the car apart in order to make it happen, I simply don't have the time for it, nor do I have the space to keep a half-stripped car parked in the corner of a garage somewhere.

And for some strange reason, I've been having 4.6 stuff quite literally dropping out of the sky, and into my driveway for little to no cost. Hell, the '97 4.6 NPI is almost just perfect for the area around here, but I wouldn't mind rowing my own gears a bit, and make it just a bit quicker.
 

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It's been years, but I think mine put down 243rwhp/246rwtq when it was a stock NA, stock 4R70W, 4.10:1 arrangement.
On what kind of dyno?
 

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My advice would be if you want a DOHC 5-speed bird, swap it into your 97, or get another 4.6 bird to start with. If you are just looking for more power, an explorer PI swap would be a direct bolt-in swap for your 97, and would get you almost as much power with no re-wiring at all. Doing a PI swap with some better cams will actually get you more power than the stock DOHC 4.6, again without having to re-wire anything. Doing this swap into the 92 would be way more work. As for what needs to be done, if you are starting with a 4.6 car, the easiest way to do the swap is to remove the old SOHC 4.6 with the engine harness still attached, label all the connectors, then lay the harness across the DOHC motor, and modify the harness outside of the car so everything plugs in, then you drop the DOHC back into the bird with the harness already attached, plug it in to the existing Tbird wiring, get a tune, and an rpm switch to operate the IMRCs if you are keeping them, and then you are done. Swapping it into a 5.0 car will require first completely rewiring the car as a 94+ 4.6 car, and then doing all the engine swap work from there.
 

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Being so new to this hobby, I am trying to understand the thought process that goes into this decision. My '97 is a blast to drive, even in stock condition. What would be the advantages/ disadvantages of a supercharger as compared to an engine swap, if one of the main goals is to preserve/improve the driving experience. I see lots of info about HP, but what about mid-range torque? Thanks for this educational moment. KF4sign (Warren)
 

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If you do a PI engine swap without a tune, or gears, or converter, then most of the time it will drive exactly the same and will have similar mid-range power and torque. The DOHC is actually down on mid-range power compared to the 2V, but it more than makes up for it with upper rpm power, so with drivetrain mods, it can be a lot faster and a lot more fun. For mid-range power and keeping drivability, nothing beats a positive displacement blower like the SVO or the TorkTech kit, but many of our cars are getting higher mileage and people may not be comfortable bolting a blower on a 150K+ mile 15+ year old engine, and if you have to swap the engine anyway, you might as well upgrade it to a PI motor. This way you have more performance, and a newer engine, and still have the ability to bolt a blower on it if you want.
 

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For a daily driver, you will not be spending much time over 3300 rpms; so the car will feel more sluggish around town, because of the lower midrange power.

Eliminating the IMRCs makes it worse.

A PI swap is much easier. (On a 96, anyway)
 

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For a daily driver, you will not be spending much time over 3300 rpms; so the car will feel more sluggish around town, because of the lower midrange power.

Eliminating the IMRCs makes it worse.

A PI swap is much easier. (On a 96, anyway)
A DOHC swap isn't that much more difficult, it's only a few more wires and a bit more patience on a 94/95 or 96/97 4.6 car. The 5.0 chassis I'm sure could be adapted just like the 3.8 but at that point you'd be doing like RaceCougar did and rewiring most of the car.
 

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Y would rebuild the 5.0 with better parts it should be a good platform for the upgrades for the 5.0 also the trans. Not to compared for the electrical nightmare for swaping a dohc into it. If it is a tremic t45 the bell housing should bolt off and swap on a bell housing for the 5.0 that you have in it. The down side to that did the car come with a 5 speed to start with if not you wound have to find a donor car that was a 5 speed. if it is a 5 speed see if the t45 can swap the bell housing from the 4.6 to the 5.0 bell housing. I found out that the t45 t56 bell housing could come off but i am not sure on the year of car you got your t45 from. the t45 that came out of my mustang when i got that t56. the bell housing from the t45 came off and a 5.0 bell housing went on i am not sure where to get one other than jeggs or summit. I know those two sites has a lot of parts for the 5.0 for engine. go that route
 

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A DOHC swap isn't that much more difficult, it's only a few more wires and a bit more patience on a 94/95 or 96/97 4.6 car. The 5.0 chassis I'm sure could be adapted just like the 3.8 but at that point you'd be doing like RaceCougar did and rewiring most of the car.
wouldn't the exhaust situation with that darn integrated cat present a "problem" for most (if you're not able to get MarkVIII exhaust manifolds)?
 

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The stock mark viii integrated cat fits fine as long as you insert the steering shaft afterwards, and have the wiper cowling removed, and use an engine load leveler, or drop the car on top of the motor installed on the subframe. Or get Kooks, not a cheap option but it fits equally tight.
 

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I'm looking at that right now. Am I correct in suggesting that in the first picture or two, that the passenger-side harness which runs over that side shock tower is the main lead from the ECM?

This thread is enlightening, but once again goes back to what I'm saying: There are extreme 'before and after' shots, where major steps have been done, and the photos skip 8 or 9 steps. Argh. Oh yeah...and he never finished the car. Curses.
Yar me matey .. the passenger side harness, is not for the ECM, the ECM runs under the dash in the factory spot on the Mark, aye, its a Mark PCM with a Mark engine bay harness and a Mark motor. Yar, the car was indeed finished, yet it be needing a paint job, I just stopped posting pictures. And im not going to give you a step 1, 2 3 play by play on HOW TO do this my way as there are MANY ways of accomplishing this task, I have over 20 years of experience wrenching on cars - and you expect an all inclusive how to article ?? For what ? What do I get in return besides complaints and criticism ?
 
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