4.6 vs 5.0

[CactusHugger11]

Can someone help explain to me the difference between the two engines besides the obvious size difference? What are the pros and cons of both engines? Which is more expensive to repair and work on etc.... Thanks

[95mustanggt]

The 5.0 is a pushrod V8. I don't know if I have to explain what that is, but if I do let me know. The 5.0 will be cheaper and easier to work on. Although the later 5.0's were computerized, the computer did not control everything. Even in the last year of the 5.0 Mustangs (1995) you could still adjust the timing with a timing light. The 5.0 is considered to have more torque in stock form and because of it's age and popularity has a massive aftermarket.

The 4.6 is an over head cam engine. The 4.6L engine uses a more advance computer and a bigger (the 4.6L block is actually bigger than the 302 block) block. Although it has been on the market for 7 years (originally introduced in the mustang in 1996) there seams to be a lag in aftermarket parts availabiliy. Although this is starting to change now. These engines are not as easy to work on and tuning items like changing timing are not possible with out a computer chip or timing adjuster.

That is just a brief look at the 2 engines, I'm sure you'll get a ton of guys who have actually worked on the 4.6L (I'm limited to the 5.0L) to respond.

[SLOW 97]

The 4.6 is more of higher revving engine as opposed to the pushrod 5.0. Also, they way people modify the engines is different. On the 4.6, basically everyone uses a supercharger because they respond exceptionally well to boost. Not as many people try to build naturally aspirated engines as they do with the 5.0. Parts are a little more for the 4.6 and they are harder to work on. The 4.6 is just now starting to have a large aftermarket. Slowly but surely it's coming along. The 5.0 engine family is pretty much obsolete now and the emphasis has shifted to the ne modular engines. Basically everything 95mustanggt said is correct.

[CactusHugger11]

thanks both of you guys for the informative responses. im not very mechanically inclined so if someone could go into some further detail in the differences between a pushrod and overhead cam. i really appreciate it.

[95mustanggt]

A push rod engine has the camshaft in basically the centre of the engine. As it turns it pushes lifters and pushrods up and down. The pushrod pushes the roller rocker up, which causes the roller rocker to push down on the valves (and open them). The Roller rockers are just that, rockers, "hinged" in the middle.
As you can imagine all these parts moving creates a little more friction (HP loss) and takes a little more time to open and close the valves (I'm talking factions of a second).

A SOHC or DOHC motor has the cam shaft in the head. As the cam shaft turns it pushes more directly on the valves. It is more efficient method of opening and closing the valves.

Most (I think all) import motors or SOHC or DOHC (single over head cam or dual over head cam ) engines.

Most ignorant ricers (and even ricer Magazines!) think that just because a mustang has a V8 that it is "old" technology. What they fail to realize is that the V8's have close to the same technology, we just have larger displacements.

[98SteedaGT]

A pushrod type engine works like this:

A cam sits in a valley in the center of the engine, it's driven by a chain from the crank shaft. This cam rotates with the engine. Directly on top of the cam are something called lifters, these can be Solid, Hydraulic or Roller. This is what transfers the lift from the lobes of the cam to a device called pushrods. Pushrods are long slender pieces of metal that are seated on top of the lifters, and as the lifters rise and fall this causes the rod to push or relase on Rocker Arms. Rocker arms can be Pedestal or Stud mounted, they also make a lot of different types, (like Roller), these rocker arms do just that, they rock back and forth exerting pressure on the top of the valve stem where the springs are. This in turn causes the valves to open and close. This all works together with Cam Timing to provide the 4 cycles of a normal car engine. Intake, Compression, Power, Exhaust (or however you say it).

An overhead type engine works like this:

There is no cam valley in the engine block, there are not lifters (at least, not like the pushrod types) The cams (2 or 4) in GTs sit directly above the valve stems/springs on top of the cylinder heads (if you notice, these heads will look a lot different at the cover, making room for the Cam Sprockets in front). These cams are linked to the engine the same as the other style, via chain or belt, but there are now two timing chains on the engine (one for each bank -left-right). These chains go to sprockets on the heads that in turn rotate the cams, the lobes on the cam push directly on to the valved themselves. This frees up some HP because the force isn't having to travel up the cam valley, through the lifters, up the rods, then to rocker arms, and then to the valves. It just goes straight to them. The 4V engines work the same, but have a main cam sprocket in front, then two smaller sprockets directly behind that link the two cams together. This is how they get the cams sync'd to each other.



If I have left anything out, someone fill it in for me.

[Snakeman]

look at guys like John Mihovitz pushing 1200+ HP from a (worked) stock cobra block!

try that with a stock 5.0l block...

well, only if you want to scatter your parts all the way down the 1320...

[gtsr515]

Well if it's worked it's not a stock block.

[Mustang92]

Originally posted by Snakeman
look at guys like John Mihovitz pushing 1200+ HP from a (worked) stock cobra block!

try that with a stock 5.0l block...

well, only if you want to scatter your parts all the way down the 1320...

As much as I like the 4.6 motors and defend them I have to disagree with you here. Mihovitz's motor is filled and is far from a stock block. Yes in stock form the 281 block is stronger there are people running well over 900 HP with no problems (Dave King, Joe Stewart, etc...) however the pushrod guys have R302 and A4 blocks available that can and will handle as much as a filled 4.6 block. Honestly the filled 4.6 block is the same thing as an R302 block except the R302 block was cast and the other is done by a shop.

What I think is more impressive is that most of the Mod Motor guys today are pushing the limits of their cars with stock heads. I can't think of any Hot Street cars running ported E7's. Mike Tymensky is running ported 4V heads. Mark Vanmeter running Renegade is using stock ported 4V heads. These are just a couple of examples.

Bill

[Unit 5302]

This is a pushrod engine. It's not normal as it's a prototype 32v 5.0L. It does, however, allow you to see the pushrods coming from the center of the engine up to the head.



Here is a picture of a 4.6L SOHC engine. Notice the curved pedestals that the camshafts ride on. One camshaft per head.



Those may be helpful.

Engine History:

The 302 or 5.0L OHV Pushrod V8 debuted in 1968 as a derivative of the 90* V8 family of Ford engines. The family of engines dates back to the 260 first released in 1962. The Mustang has had the 302 as an option from 1968-1973, 1975-1979, and from 1982-1995.

Properly cared for, a 5.0L engine should turn 120,000mi onto the clock before any noticable performance drops occur. It's a very reliable and proven engine.

The 281 (4.6L) has been around since 1992. It was first placed into the Crown Victora sedans 11 years ago. The Thunderbird got it in 1994, I believe, and the Mustang in 1996. There are a couple different varients of the engine. The SOHC, found in the Mustang GT, and the DOHC Cobra engine found in the Mustang Cobra. If you are comparing 5.0 vs 4.6, I'm going to assume your looking at the SN95 series cars, and quite frankly, the GTs. The DOHC Cobra is expensive as all get out. If you can find one in good condition, with low mileage for less than $16,000, you're doing well.

So far, the 4.6L has proved to be a sound, reliable engine, with few problem areas. The intake manifold on the older GT's is definately one issue. There is a replacement recall which allows you to get a different one when you stock one pops. You'll find few 4.6 GTs with 100k or more on them.

Engine performance:

The 5.0L can be built for whatever you want it to do. There is an aftermarket product to meet your needs. You can retain mostly stock driving charachteristics with a 320hp combo that'll set you back about $2500, new. If you can do the work 320hp is about $2000. Or you can build a streetable engine to make as much as 375hp with EFI on the 302, or going to a stroker can net you N/A performance in excess of 400hp. Spending under $4000 for a streetable 400hp engine isn't hard to do with the stroker 5.0, providing you can do the work. You can get a fully assembled 306 long block and slap heads and a cam into it for well under $5000 and make 350hp+. Incon makes a twin turbo kit that can push an otherwise stock 5.0 to over 400hp easy for about $4000. Adding a small supercharger and a light N/A build can net well over 350hp for under $3000. An intercooled S/C like ATI Procharger can make 450hp pretty easy, again for around $4000. If you really wanna go nuts, the sky's the limit. If you're on a really tight budget, slap a 125hp shot onto the SN95 5.0 for $500.

The 4.6L can make power with some S/C kits out there as well. If you plan on going N/A, you might be able to pull out 320hp by doing a PI head swap, and adding some other parts. You can pull it off for under $2500 if you can do all the work. You'll probably have to be keeping the CR high to pull it off.

The 4.6L isn't as strong as the 5.0L is, stock for stock.

In stock form, the pre 99 4.6L is NOT more rev happy than the 5.0L OHV pushrod engine. I don't know why people keep saying that it is. Just because a car is OHC vs OHV doesn't mean on the street one will be more rev happy than the other. Neither the Gen 1 4.6L nor the 5.0L is a happy engine for much above 5,000rpms off the factory floor in the SN95 Mustang. Also, off the floor, the SN95 5.0L will walk a 4.6L. There shouldn't be a lot of debate about that. It's pretty well documented off the floor the 4.6L GT is a low 15 car, while the same really good driver could probably churn a real high 14 out of the 5.0L.

Repair time:

As far as working on the engine, the 5.0L is like a bucket of legos. The 4.6L is more difficult to work on and access. Some people seem to view OHC technology as "black art." Talk to most motorcycle mechanics (not Harley guys), and they're likely to tell you it's not so bad. Accessibility is the name of the game when it comes to easy to work on, and the 5.0L has the advantage hands down.

Expenses. The 5.0L is cheaper to repair. It's computer systems and electronics are less intrustive, and the parts are easier to find. It's a competitive market out there. If you blow something up, the 5.0 is WAY WAY cheaper to repair. Straight from DSS's site.

Our 4.6 short blocks feature all the same tricks that our record setting Bullet short blocks feature. Torque plate honing and deck equalization are the key to great ring seal. Forged pistons and rods are what is needed for strength.

You would not believe how many 4.6's with a couple of thousand original miles have been through our shop already. It is very expensive to break one of these motors first and then rebuild it. It was common with 5.0's to blow them up first and then pick up the pieces. If you trashed everything it was no big deal, you were going to buy everything new anyway. Not true with a high buck aluminum block or overhead cam head.

What is it you're truely trying to get at with this question, CactusHugger11?

[CactusHugger11]

i never really understood the difference between the two engines before. i knew they were different but i dint know how. thanks to everyone for all the usefull information.

[Snakeman]

by "stock block", i mean that they start with the same casting that the normal cobras ship with, go much over 600 HP with a stock 5.0 block and soon you'll end up with a pretty nice boat anchor...

SHM claims their 800+ HP shortblock is "...the same one used by John Mihovitz...". they don't mention any "filling" though, just the addition of billet rods and oil pump gear and a girdle...of course, just because they don't mention it, don't make it so...

anyway, that's where i got my info.
just parroting what i've read...