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View Full Version : 4.6L SOHC Engine swap to 1995 5spd SC



SR71BLACKBIRD
08-04-2005, 05:24 AM
I am needing to replace the motor in a 1995 SC 5spd and am looking at going with a 4.6L Crate motor. And will probably drop a Supercharger on it.
Wouldn't be an SC without one would it?

I am not sure what all this will entail.

Radiator? Tranny? K-Member? Wiring harness? etc....

Does anybody have any advice to give to a new SC guy?

ANY! Help would be greatly appreciated.
And the best advice will win a Half Rack of their favorite beverage.

Thanks in advance,
Jim

CaifanSC
08-04-2005, 08:14 AM
Dont do it man. 95 5speed sc's are the rarest ones to come by. You would be messing it up by doing an engine swap. Whats wrong with the engine?

99GSXR750
08-04-2005, 08:58 AM
I am needing to replace the motor in a 1995 SC 5spd and am looking at going with a 4.6L Crate motor. And will probably drop a Supercharger on it.
Wouldn't be an SC without one would it?

I am not sure what all this will entail.

Radiator? Tranny? K-Member? Wiring harness? etc....

Does anybody have any advice to give to a new SC guy?

ANY! Help would be greatly appreciated.
And the best advice will win a Half Rack of their favorite beverage.

Thanks in advance,
Jim

Your 5 speed will not bolt to a 4.6.

XR7 Dave
08-04-2005, 09:01 AM
Good luck bud, you'll have to change the transmission too. There are a lot of wiring differences between the SC and LX so you'll need to be savey on that too. There's a guy with a sweet 4.6 with a Vortech and 5spd that I've seen run. It's almost as fast as my V6. :) Definititely sounds very cool.

My point is the V6 can be just as fast up to a point for less/same money. Of course if you are planning on 600rwhp then the V8 is the way to go but it will still cost a small fortune. :)

racecougar
08-04-2005, 04:12 PM
As others have already said, don't do it. 95 SC's are rare enough, not to mention 5-speed 95's.

But, if you have any specific questions on the swap, send me an email at [email protected], and I'll do my best to answer them. I swapped a 4.6L DOHC into a 90 XR7 awhile back.

-Rod

Randy N Connie
08-04-2005, 04:28 PM
If you wanting to build a 4.6 with supercharger.
I would start with a 2003 or 04 Cobra.Buy a complete
Cobra from a junkyard.Then you would have most
every part needed.Should be able to get one for
around $10,000.00

www.junkyarddog.com

Micahdogg
08-04-2005, 05:00 PM
A 4.6L with a supercharger to replace the 3.8L with supercharger. Hmmm....to be honest, it would simply be a novelty. You would get a cool V8 rumble too, but that would be it. No matter what brand blower you went with, you would be somewhat boost limited on the motor because you would have weaker cast pistons and crank. Therefore, the most you could really hope for is 300ish RWHP. And for that kind of power, you would be spending a LOT of cash. Even if the motor were free you would have to buy the supercharger kit?

Or you could spend the doe on a supercharger for the 4.6L for an AutoRotor for the 3.8L and be at the same HP level with a lot less headache (getting the motor in there, getting the wiring straightened out, adapting a 5 speed tranny, etc....

If you are bent on a 4.6L, I would just buy a 4.6L and make that your platform. It would be easier to swap ground effects and a T45 than to go the route you are explaining.

Micah

SR71BLACKBIRD
08-05-2005, 03:14 AM
Thanks for all the advice.

First off I wanted to make a correction, it's actually a 1994, not that it matters much I suppose but I know how car guys are about technical stuff.

This is a great technical forum.
You guys know more about these rides than 99% of the mechanics out there.

I talked with Denny Aldridge of Aldridge Motorsports and he pretty much told me the same stuff.
But he sold me when he said he could get me 350-400RWHP and keep the 3.8L platform. Which I am sure will be worth more down the road.

I still have a goal of building a 600+RWHP Vette eater but I will probably take some of your advice and start with a 4.6L LX platform. Alot of advantages there that I saw once the smoke from burning tires cleared from my vision.

1 It will be alot easier to swap Trannys than motors.
2 The project car will be much cheaper.
3 If I convert an LX, no one will give a rats ***.
4 If I reduce it to a smoldering pile of crap wreckage, no great loss.

Although I'm not thrilled about dropping several Grand I can't wait to drive it.

Thanks again everybody,
Lets talk shop again soon.
Jim

darkstar_one
08-05-2005, 03:31 AM
yep. you would want to go with a 4.6L DOHC 32 VALVE. Thats the only way to go. Either that or a 5.0. I would preferablly drop in a 5.0L CAMMER ENGINE. Oh yeah baby! But its you man. I dont think there are many aftermarket parts for the SOHC 4.6L. And if they are i hear they suck!

SanDiegoLXBird
08-05-2005, 04:29 AM
I dont think there are many aftermarket parts for the SOHC 4.6L. And if they are i hear they suck!

I hope that's a joke. ANd if it isn't, just stop talking. Please.

Micahdogg
08-05-2005, 10:19 AM
First off...if your homie can pull 350-400RWHP out of an SC...definitely keep us updated. I don't recall ever hearing that name around the SC community, so if he's going his own direction for go fast goodies it would be very good for us to learn about what he's doing. It's taken us well over 6 years now to consistantly get into the 350-400RWHP range and it was no walk in the park.

Second....I'm not so sure I would go with a 32 valve 4.6L. In fact, I know that I definitely would NOT go with one. I'm really sold on the SOHC explorer motor. They are cheap....like under a grand. Plus they have the 70lb lighter aluminum block with cross bolt mains (effectively the 6 bolt main cobra block) with PI heads. The motors are generally cheaper, more compact and keeps the stock look in a 96-97 T-Bird LX. I've got visions of assembling an Explorer motor with more aggressive cams, some mild porting, flat black underdrives, chip, gears, etc.... having a 13 second screamer that doesn't look modified.

Micah

SR71BLACKBIRD
08-06-2005, 01:33 AM
Thanks for helping out Dogg,
It may be a few weeks before the work is complete and I can pay for it but I am sure I will be letting everyone here know all about it. Like who else is gonna care right? Other than a jealous Bowtie enthusiast who won't believe me anyway! ;)

Blackbird


First off...if your homie can pull 350-400RWHP out of an SC...definitely keep us updated. I don't recall ever hearing that name around the SC community, so if he's going his own direction for go fast goodies it would be very good for us to learn about what he's doing. It's taken us well over 6 years now to consistantly get into the 350-400RWHP range and it was no walk in the park.

Second....I'm not so sure I would go with a 32 valve 4.6L. In fact, I know that I definitely would NOT go with one. I'm really sold on the SOHC explorer motor. They are cheap....like under a grand. Plus they have the 70lb lighter aluminum block with cross bolt mains (effectively the 6 bolt main cobra block) with PI heads. The motors are generally cheaper, more compact and keeps the stock look in a 96-97 T-Bird LX. I've got visions of assembling an Explorer motor with more aggressive cams, some mild porting, flat black underdrives, chip, gears, etc.... having a 13 second screamer that doesn't look modified.

Micah

racecougar
08-06-2005, 05:01 PM
Second....I'm not so sure I would go with a 32 valve 4.6L. In fact, I know that I definitely would NOT go with one. I'm really sold on the SOHC explorer motor. They are cheap....like under a grand. Plus they have the 70lb lighter aluminum block with cross bolt mains (effectively the 6 bolt main cobra block) with PI heads. The motors are generally cheaper, more compact and keeps the stock look in a 96-97 T-Bird LX. I've got visions of assembling an Explorer motor with more aggressive cams, some mild porting, flat black underdrives, chip, gears, etc.... having a 13 second screamer that doesn't look modified.

Micah

Yeah, but the DOHC 4.6's can look soooo good in a MN12:

http://members.tccoa.com/racecougar/showcar/showcar%20engine.jpg

When they aren't all dusty, that is. :)

Plus, the pre 03 DOHC's have the aluminum 6-bolt main block, too.

-Rod

95pearlbird
08-06-2005, 05:34 PM
Hey Bud,
Would have to agree with a lot of the comments already posted.
If you want a V8, start with an LX that already has one. There are still a lot of "birds out there with under 150K, and they are fairly cheap. You can search for specific years on autotrader.com with a nationwide search. You will also find SC's on here in the 100-180K(miles) range for under 5 Grand.
Realize first of all, its going to be heavier, and with the limitations of stock crank and pistons in the 4.6, you don't want to stress it too much. That's why it was mentioned to go with a junkyard Cobra engine. All the good internals are already there, and you need that to even consider putting a blower on it. You will need the trans also, and a BIG shoehorn, to put this in an SC! It can be done, but is a lot of work, and pretty involved! Start with an LX first. But then you won't have all the goodies the SC comes with. Incidentally, yes, the '95 5-speed is more rare than the '94 5-speed, the production numbers are higher for the '94.
Honestly, your best bet is to just pull out your 3.8 V6, crate it up and send it off to Coy Miller for either a Stage I or Stage II Rebuild. He has many very satisfied customers here in SC-land, and when you stack it all up (including all the labor) the prices are actually very reasonable! The main thing is that YOU WILL NOT BE DISAPPOINTED! That in itself is priceless. You will also have a fresh SC that retains its "stock" configuration, thereby actually making it worth more! Figure it out on paper... you will actually be saving money, as opposed to swapping out with an 8.......and weight.:)

Micahdogg
08-08-2005, 10:49 AM
It's been my experience that the LX 4.6L birds are almost always lighter than an SC. Even if the motor is heavier (which I doubt), the entire car is easily 150-200lbs lighter on average. A friends 95 4.6L weighed in just over 3700 when checking the scales at the track. On a good day mine is over 3900.

Also, Coy Miller would not be the best option. That would be a $7500 option that would turn to $10,000 after cost of crating, shipping to VA and buying supporting pieces for the engine that don't come with the build up like injectors, fuel pump, exhaust, MAF, TB, and it would be backwards to not upgrade the blower to something better than a run of the mill stock M-90.

For $3500 you could get the AR and with absolutely nothing but exhaust be putting 280-290 RWHP down. Of course 300 is just a fuel pump, injectors and C&L meter away.

Micah

007_SuperCoupe
08-08-2005, 03:07 PM
It's been my experience that the LX 4.6L birds are almost always lighter than an SC. Even if the motor is heavier (which I doubt), the entire car is easily 150-200lbs lighter on average. A friends 95 4.6L weighed in just over 3700 when checking the scales at the track. On a good day mine is over 3900.

Also, Coy Miller would not be the best option. That would be a $7500 option that would turn to $10,000 after cost of crating, shipping to VA and buying supporting pieces for the engine that don't come with the build up like injectors, fuel pump, exhaust, MAF, TB, and it would be backwards to not upgrade the blower to something better than a run of the mill stock M-90.

For $3500 you could get the AR and with absolutely nothing but exhaust be putting 280-290 RWHP down. Of course 300 is just a fuel pump, injectors and C&L meter away.

Micah

The AR is not just a simple bolt on either. You have to have a better IC, larger fuel pump, larger injectors, different MAF. $3500 simply won't get the AR on your car. Closer to $5k to get it on with all the supporting parts if you're going from a stock car. I know, because I'm doing it right now. I'm getting my SC all set up for the AR. But the AR is the cheaper and faster way to go to get to over 300 rwhp. With a built car (heads and cam) you'll be looking at closer to 400 rwhp, but a lot more money.

Micahdogg
08-08-2005, 04:51 PM
Not true. All you NEED for the AR is $3200 (last price I saw) and $200 in exhaust work. That'll get you over 270RWHP. Dalke was getting 296RWHP with just an intercooler beyond that.

So that tells me with a C&L 73mm MAF with 42# tube for $180 tops, set of 8 42# injectors new for $250 to your door and a 255 fuel pump for $130 you could clear 300RWHP...through a paper filter and on stock IC. And if you hit the rollers (usually $75 for 3 pulls) you would have gotten a tune to seal the 300RW deal.

But yes, the AR will work on 100% stock everything....and if you open up the exhaust it should support 270RWHP with no other mods.

Even if you supercharged a 4.6L and ran with the 6# pulley (typically used on a stock 4.6L with mileage) you would be lucky to be over 270RWHP.

Micah

P.S. Last I checked, when you sign up for a Coy Stage II, Coy will strongly suggest you upgrade the other parts like I mentioned before. Even with that stuff he was getting 440HP at the crank. His motors typically ran 300RWHP with these parts in place. If you want nothing other than his $7500 motor you power would only be increasing from heads/cam (the roller rockers and titanium valvetrain would wash from the increased friction of a fresh rebuild IMO). YOu don't need a built race engine for that. And quite frankly, just his heads and cam on a stock everything else motor would be LUCKY to break 250RWHP. For $7500.

Compare that to an AR with stock everthing for half the price and you'll blow 250RW out of the water.

SR71BLACKBIRD
08-08-2005, 06:29 PM
Although the AR setup will be something I need to do in the future.
The original reason behind doing this was because I have a Rod bearing going out and need to rebuild the motor.

I am convinced that I can pull the power out of the 3.8 with a proper build up so the motor swap is now off the table.

As far as the AR setup I don't think that would answer my immediate concern which is a motor going bad.

By the way how long do you think the motor would hold up to an AR setup with a rod bearing going?

Thanks for all the advice guys,
lets keep these bad birds rolling.
Jim

007_SuperCoupe
08-08-2005, 06:33 PM
Micah,
I don't want to get into a contest with you here. I've seen the AR in action, and there are a few things that you're missing on. Remember that even though Dave D. was getting 294 RWHP on the AR and a few other mods, he did it at 4200 rpm...and then ran out of fuel. First off, you need 50 lb injectors minimum. Ask Julian Miller why... 42s just don't cut it, even on an otherwise stock engine. Last time I checked, it was around $500 for an exhaust, and that's getting a deal. I wouldn't run the AR with anything less than a full exhaust behind the manifolds. MAF is a must as is a better IC. Even though the AR is more efficient than the M90, it still requires an IC. And it better be better than stock because of the amount of air passing through it. So lets go back to the math boards and see what we're up to now...

Base price for the AR: $3200
MAF: $180
50lb Injectors: $300
Fuel Pump: $130
Exhaust: $500
Double IC: $450
SCP Chip: $300
Dyno time for a tune: $100

That adds up to $5160 plus tax where applicable. Even knocking the IC off it's still $4710, close enough to call it a budget of $5k. If you can get in on some GPs you may get that $5160 down to about $5k, but in order to get power above 4200rpm, that is the MINIMUM that you need to safely run the AR on an otherwise stock SC. Add a TB and you up that by another $240.

I'm not arguing that Coy is the way to go. I'm not, nor would I recommend him to any of my friends. I can get better performance for less locally. I just think that the AR needs to be accurately represented. You very well may be able to get 270 rwhp out of the AR with nothing more than exhaust, but who wants to run out of fuel at 4000 rpm? I've got my rev limiter set at 5500 rpm and wish that I didn't have to. But to keep it safe, that's what I have to do until I get larger injectors.

Like I said Micah, I don't want to step on any toes here. But the truth is that it takes more than just slapping on an AR to make power. If you disagree with me, then that's fine. Better your SC than mine. I'll do it the right way to make power...and if someone asks...(as is the case here) I won't steer them down the wrong path.

SR71BLACKBIRD
08-08-2005, 07:03 PM
Thanks for the advice.

Sam,
I am getting a pretty nice bulid up from Aldridge Motorsports out here in Portland. He says he will deliver 350+ RWHP but I want to make sure it is still going to be a high mileage motor as I can't afford to drop $7-8000 bucks evry couple of years. Do you have any advice on internals that I need to be aware of?

Also,
I have a true Borla 2.5" Dual exhaust on thh car and will soon have a complete rebuild. What else do I need to handle a AR Blower system?

Thanks,
Jim

seawalkersee
08-08-2005, 09:43 PM
Wow...and I mean WOW. That is the most technical arguement that I have ever seen. And, the thing gives me what I need to know to make the good HP. I thought the AR kits were closer to the 400 HP range. If I am not mistaken though, last run I saw numbers on, the HP passed the TQ at likd 4700 and was near 440 at the rear wheels. THAT WOULD BE NICE.

Chris

007_SuperCoupe
08-08-2005, 11:22 PM
Sam,
I am getting a pretty nice bulid up from Aldridge Motorsports out here in Portland. He says he will deliver 350+ RWHP but I want to make sure it is still going to be a high mileage motor as I can't afford to drop $7-8000 bucks evry couple of years. Do you have any advice on internals that I need to be aware of?

Also,
I have a true Borla 2.5" Dual exhaust on thh car and will soon have a complete rebuild. What else do I need to handle a AR Blower system?

Thanks,
Jim

The stock internals have been proven to take in excess of 440 rwhp, but I don't know what the longevity of the motor would be. With a rebuild, you want to keep certain things in perspective when it comes to quality. Don't skimp on the bearings. Get the best. For the little more that it costs, you'll be better off. Then depending on your ultimate end goals decide what you need internally. The stock crank is good. You could go with '94-'95 connecting rods with forged pistons (and also go with the best connecting bolts, studs...ARP). This combinations should be good for sustained 400 rwhp...but I wouldn't push it much farther. You could look at 351 W I beams and custom pistons (a lot of SC's have this combo) which is stronger yet. Bottom line is with 350 rwhp, stock internals are really enough, but you could look at forged pistons for that extra added durability. Also the '94-'95 oil pump is better than ealier years. Definately go with high quality fastners and bearings along with a bit stronger rods. Forged rods would be better, but I honestly haven't looked into whether they are offered for our 3.8 or not.

As for what you need for the AR...my previous post pretty much says what I'm doing. That's the way I'd recommend others go about it as well. That with a VERY mild cam will get you in the ball park of 310-330 rwhp with some minor head work getting you the rest to 350 rwhp.


And seawalkersee,
The AR is a 80-100 rwhp BOLT on, with the correct supporting mods. Still it's a hell of a bang for the buck. Heads, cam and snow perfomance kit will yeild VERY impresive results as most of us have seen from Dave D.

seawalkersee
08-09-2005, 05:57 AM
I did see that. However, I would like to know how the HP passed the TQ. To me that would seem that there was a restriction somewhere. I have never seen or delt with that before so I dont even know what to question. As far as the rebuild goes, why are the 94+ rods better?

Chris

007_SuperCoupe
08-09-2005, 09:17 AM
seawalkersee,
It's not uncommon to see higher hp ratings than torque ratings in other cars. It isn't seen in SCs generally because the torque peaks early, and the VE (Volumetric efficiency) of the engine is not great enough to produce better power at higher rpms. Then in Dave D's case (as others who have similar heads) when the VE is where is should be, the supercharger cannot keep up to provide enough airflow for the heads. Now in Dave D's case he's also got one other little trick that increases VE at high rpms...a Randy Baker intake manifold. That allows for much more air to enter the heads at higher rpm, allowing for more rwhp. There isn't a restriction, but rather one removed that is on nearly every other SC out there.

I haven't looked into '94+ rods as I'm going with 351 W rods in my rebuild, but I do know that they are stronger than the earlier rods. I don't know the particulars though as I really haven't looked into them closely.

Micahdogg
08-09-2005, 11:03 AM
I'm not in a contest. But just because you think it's absurd to bolt on an AR without components in place to support it's full potential is no reason why you can bolt it on with minimal mods and enjoy something in the 270RWHP range for far less than the numbers you are throwing out. Why would someone want to buy an AR and ONLY be limited to 270? Well, the signature says it all. But at least with an AR you have the flexibility to go from mild to wild whenever you want to pulley it up for 400RWHP goals. With a Coy package, you need all the goodies to even see the numbers he's touting on the site which was my entire point.

Micah

P.S. The $300 chip was included in the package providing you pony up $75 for the dyno time with a WBO2.

seawalkersee
08-09-2005, 11:04 AM
Cool, thanks man. I believe what you are saying is that the VE of the engine has reached 100% and there is NOW not enough air to lower the percentage back to a range that could improve torque. It sounds right in my head...the engine is outrunning the air supply. Then why does it continue to build HP?

Chris

007_SuperCoupe
08-09-2005, 03:31 PM
Dave D's car has teh VE to allow for the HP to continue to climb at higher rpms. HP and Torque are directly proportional to one another. Depending on what expert you listen to, either is derived from the other. The VE of a stock engine is sufficient for stock power levels. There is not enough rpm to display the lack of VE at higher rpms. Now, about the 100% VE...on a forced induction engine, VE can be much higher than 100%, depending on CFM flow from the (in our case) supercharger. In Dave D's case, his supercharger is keeping up with what the engine is capable of. In stock form, the engine and stock M90 are pretty comparable. The engine can take a bit more air than the M90 is capable of providing. Which is why minor porting and overdriving the sc results in more power. There is a limit though with stock heads, cam and M90. The largest limiting factor is the fuel system though. Take my car as an example:

go fast mods include:
76mm MAF
70mm TB
Ported Gen II M90 w/ port matched inlet plenum
5% pulley
Custom 2x IC with IC fan
Custom Exhaust
Shift Kit
Tune by Dave Dalke

Right now my mods are pretty evenly matched with my fuel system. But even with a 255 lph fuel pump, I run out of fuel at 5200 rpm. Peak power with stock heads, cam and M90 is around 5k rpm. With the mods I have right now, adding an AR to the mix without upgrading injectors, will put me at peak power just below 4k rpm. Granted, I'd be making more power faster, but my useable power band would be so small that my car as it is now, would probably end up being faster in the 1/4. And even with a good tune, you'd have to have the rev limiter set so low that you'd constantly be hitting it. It would be even exagerated more in a 5-speed SC because now instead of 2 shifts in the 1/4, you'd be making 3, or maybe even into 5th gear.

I'm sure that Dave D. will also strongly recommend that there are MINIMUM mods that have to be installed on a SC in order to SAFELY run an AR. I've spoken with him about it extensively while preparing my SC for the AR.

And Micah, the $300 chip is included so long as you install all the mods at once. But 99% of the club doesn't have that much money to drop at once to install mods. Most have to do it on a budget and in so doing, they will need the tune long before the AR. That is why the price is broken out. I don't know if Dave D will provide a "discount" if you already have an SCT chip, but I'm guessing there won't be much of a discount. I'm just trying to be realistic when it comes to modd'ing a SC. From what I've seen, over 80% of the people on this site, just through parts at their SC instead of carefully planning their mods out. I personally believe that is the biggest reason there are so many who blow their HG. I've taken great care to mod my SC in a way that will best prevent premature HG failure. Bottom line is that it is not a direct bolt on and go.


Cool, thanks man. I believe what you are saying is that the VE of the engine has reached 100% and there is NOW not enough air to lower the percentage back to a range that could improve torque. It sounds right in my head...the engine is outrunning the air supply. Then why does it continue to build HP?

Chris

seawalkersee
08-09-2005, 10:16 PM
Just a touch off subject BUT, did you guys see the magnaport III. Check it out on the new products thread.

Chris

Ty Whutaker
10-10-2005, 04:59 PM
please explain the tranny swap. i understand the 5-speed and the 4.6 to be compatible...


Good luck bud, you'll have to change the transmission too. There are a lot of wiring differences between the SC and LX so you'll need to be savey on that too. There's a guy with a sweet 4.6 with a Vortech and 5spd that I've seen run. It's almost as fast as my V6. :) Definititely sounds very cool.

My point is the V6 can be just as fast up to a point for less/same money. Of course if you are planning on 600rwhp then the V8 is the way to go but it will still cost a small fortune. :)

racecougar
10-10-2005, 08:13 PM
please explain the tranny swap. i understand the 5-speed and the 4.6 to be compatible...

The bellhousing bolt pattern for a 3.8/5.0/5.8L is different from a 4.6/5.4L.

-Rod