Mod motor guys...need experienced advice/opinions about 4.6 longevity...

[Back2Mustangs]

1996 GT...driven by some guy for around 300 miles a weeks, he says. Car has 144K miles. I'm thinking, "worn out!"...I may buy this car, and if I do I'm already planning to build a new bottom end for it with a DSS iron block and forged internals. If this was a 302 with 140K on it I wouldn't worry hardly at all, but I don't know how long these recycled beer-can motors last! Please give me some advice on what condition this motor should be in for the miles it has. Thanks to all in advance.

 

[reeber]

I have 100,000 on my 96 and it runs great.. for now...

 

[Back2Mustangs]

Did you buy it new?

You don't notice the engine seeming 'tired' or using oil? Of course I'm not going to put any serious mods/stress on a stock 4.6 bottom end...thats what the DSS will be for, but I guess I just want to know, with that many miles is the thing gonna blow any time soon ya think? Anyone have trouble with the rings or excessive oil blow-by with high miles? Any issues with the stock valvetrain lasting that long?

I guess I'm just a little scared and untrusting of something I have no experience with. I'm a die hard Iron Block, 5.0 fan, and I always viewed the aluminum blocked, modular 4.6's to be weak. No offense meant, thats just the way I have always perceived these motors. I'd like for people with experience with the 4.6 now to show me that it can be a strong motor. I mean Ford starting using it way back in the Crown Vic's, so I know its got a little history...and its replaced the 5.0, which I have always trusted and bragged about Ford for being tough, built well, and made to last. I was a little proud to see Ford put an iron block back in the Cobra in '03...with Manley rods and forged pistons...but the 4.6 is still everywhere. How tough is the 1996-1998 motor? Can it handle 144K miles and keep on ticking?

 

[billyfe390]

If it was serviced regularily you shouldnt have any problems. I tore mine down at 104000 miles and I had less than .001 taper in all of the cylinders. Most 4.6's that have had a good service interval and have not been thrashed will outlast a 5.0 pretty easily. For example I had a 95 crown vic police car. I bought it with 104000 miles and sold it to a friend when it had over 150000 on it. Up until it was totaled at 278000 it burned 1 quart of oil every 2200 miles.

BTW its not totally a recycled beer can. The block on a 4.6 is one hell of alot tougher than a 5.0. The heads yes but the rest of the motor no.

 

[showstopper2]

buy it cheap and if it blows just order a forged crate engine with the money you save on the purchase.

 

[Back2Mustangs]

Now we're exercising those brains!

BTW its not totally a recycled beer can. The block on a 4.6 is one hell of alot tougher than a 5.0. The heads yes but the rest of the motor no.

Really? I'm a very logical, rational, realist, so I soak up pertinent facts like a songe. If you have specs on the block's strengths or numbers to back that up I'd really like to see them. If that is true and you can prove it, I'll be converted...but I don't see how any aluminum block can stand up to the abuse of N20 or boost better than an iron block...because then what would be the reason for aftermarket Iron 4.6 blocks if aluminum 4.6's are already tougher than iron 5.0L's?? Is the 4.6 block 'webbed' like an LS1? Also, anyone know how much lighter the bare 4.6 block is than an iron 302?

 

[billyfe390]

Really? I'm a very logical, rational, realist, so I soak up pertinent facts like a songe. If you have specs on the block's strengths or numbers to back that up I'd really like to see them. If that is true and you can prove it, I'll be converted...but I don't see how any aluminum block can stand up to the abuse of N20 or boost better than an iron block...because then what would be the reason for aftermarket Iron 4.6 blocks if aluminum 4.6's are already tougher than iron 5.0L's?? Is the 4.6 block 'webbed' like an LS1? Also, anyone know how much lighter the bare 4.6 block is than an iron 302?

The only aluminum block 4.6's that came in mustangs were the 96-01 cobras. The GT has an Iron block as well as the 03+ cobras. The stock GT iron block itself is capable of handling 700+ hp the internals are a different story but the block is good. There are quite a few cobras running around with 500-600+ at the wheels on the stock aluminum block with forged internals. No stock iron 5.0 block will do that without serious core shift and main bearing walking. The GT iron block is a deep skirt cross bolted block and the aluminum one is a 4 bolt main cross bolted block. Either way the deep skirt cross bolted block is miles ahead of the ls1 in terms of strength. I am not discounting the strength of the LS1 but the 4.6 block by design is inherently stronger. I am not aware of any aftermarket iron 4.6 blocks SHM is making aluminum race blocks. The internals of every 4.6 except the 03+ cobras are the weak point not the block they simply will not handle that power the rods tend to snap around 450 bhp or around there anyway. If you want to speak to an authority on this subject email either jim@vtengines or scott@vtengines .

 

[dkshadow]

Werd...

The block itself is stronger than the 5.0s.

 

[Defleshed]

the 4.6 engines are incredibly durable if taken care of. Cops use em in the crown vics, the ford explorer uses it, and hell, even many of the billions of taxi cabs going all over the earth use em. They're phenominal engines.

 

[cmb91LX]

The only aluminum block 4.6's that came in mustangs were the 96-01 cobras. The GT has an Iron block as well as the 03+ cobras. The stock GT iron block itself is capable of handling 700+ hp the internals are a different story but the block is good.

Finally, intelligence has reared its ugly head

 

[Premium Speed]

The only aluminum block 4.6's that came in mustangs were the 96-01 cobras. The GT has an Iron block as well as the 03+ cobras. The stock GT iron block itself is capable of handling 700+ hp the internals are a different story but the block is good. There are quite a few cobras running around with 500-600+ at the wheels on the stock aluminum block with forged internals. No stock iron 5.0 block will do that without serious core shift and main bearing walking. The GT iron block is a deep skirt cross bolted block and the aluminum one is a 4 bolt main cross bolted block. Either way the deep skirt cross bolted block is miles ahead of the ls1 in terms of strength. I am not discounting the strength of the LS1 but the 4.6 block by design is inherently stronger. I am not aware of any aftermarket iron 4.6 blocks SHM is making aluminum race blocks. The internals of every 4.6 except the 03+ cobras are the weak point not the block they simply will not handle that power the rods tend to snap around 450 bhp or around there anyway. If you want to speak to an authority on this subject email either jim@vtengines or scott@vtengines .

listen to this guy...

back2mustangs - you must be VERY new to the 4.6 crowd...these motors are known to go 200k miles with routine maintenance. my friends 99 GT has 190k miles on it and still runs very smooth. he said it burns 1/2 a quart every 3-4k miles and he still races it on a regular basis. the rods and intake are the weak points IMO.

 

[grodgers]

The only aluminum block 4.6's that came in mustangs were the 96-01 cobras. The GT has an Iron block as well as the 03+ cobras.

'03 and '04 Mach-1's have aluminum blocks...

 

[Back2Mustangs]

The only aluminum block 4.6's that came in mustangs were the 96-01 cobras.

Now that I did not know! And yes, I am 100% new to the 4.6 modular world. Thats why I'm doing my homework and asking people who know instead of reading crap out of some magazine before I go buy. So then a 1996 GT's block is cast iron huh? Well that alone makes me feel tons better. I haven't done a whole lot of searching for aftermarket blocks but I saw that DSS offers their "level 10" and "level 20" 4.6 iron blocks. So basicly all that has to be done is replacing the internals with forged crank & pistons...some strong rods, and the bottom end should be fairly stout? DSS also has forged internal kits, but they are like $1300.00. That sounds to me like the usual DSS high pricing.

Well you guys have been really helpful...I really appreciate the info, and I invite you all to my next thread about aftermarket 4.6 heads!!

 

[mrpositraction]

Our you saying that the 4.6L in a GT has a 4 bolt main. And if you could explain what a deep skirt cross bolted block is. I know this may be hard but I'll take what you got.

 

[bdcardinal]

a deep skirt block is one where the crankshaft is completely inside the block. usually motors have the crankshaft counterweights go below the oil pan line. the metal is fairly thick in the 4.6 blocks, both aluminum and iron. the iron blocks have 4 bolt mains, there are 2 center bolts, then on the outside there are 2 jackscrews or locating dowels(different on romeo vs windsor), and then it has 2 bolts on the outside that face inward(side bolts, if you look above your oil pan gasket you will see them. the aluminum blocks have the same setup, however instead of jackscrews or dowels, it has bolts.

 

[mrpositraction]

a deep skirt block is one where the crankshaft is completely inside the block. usually motors have the crankshaft counterweights go below the oil pan line. the metal is fairly thick in the 4.6 blocks, both aluminum and iron. the iron blocks have 4 bolt mains, there are 2 center bolts, then on the outside there are 2 jackscrews or locating dowels(different on romeo vs windsor), and then it has 2 bolts on the outside that face inward(side bolts, if you look above your oil pan gasket you will see them. the aluminum blocks have the same setup, however instead of jackscrews or dowels, it has bolts.

Thanks, everything is clearer now. That is the answer I was hoping for.

 

[kirkyg]

You don't notice the engine seeming 'tired' or using oil? Of course I'm not going to put any serious mods/stress on a stock 4.6 bottom end...thats what the DSS will be for, but I guess I just want to know, with that many miles is the thing gonna blow any time soon ya think? Anyone have trouble with the rings or excessive oil blow-by with high miles? Any issues with the stock valvetrain lasting that long?

I guess I'm just a little scared and untrusting of something I have no experience with. I'm a die hard Iron Block, 5.0 fan, and I always viewed the aluminum blocked, modular 4.6's to be weak. No offense meant, thats just the way I have always perceived these motors. I'd like for people with experience with the 4.6 now to show me that it can be a strong motor. I mean Ford starting using it way back in the Crown Vic's, so I know its got a little history...and its replaced the 5.0, which I have always trusted and bragged about Ford for being tough, built well, and made to last. I was a little proud to see Ford put an iron block back in the Cobra in '03...with Manley rods and forged pistons...but the 4.6 is still everywhere. How tough is the 1996-1998 motor? Can it handle 144K miles and keep on ticking?

Um the engine you have is an iron block. You have aluminum heads (except the non-PI heads )which have a proven track record in the performance realm. You also wont have to worry as much about headgaskets with the new ohc engines. Imo the newer engines are even more reliable than the 5.0L. I know its hard to find something 'new' thats built as well as an older product rigidity wise but in some cases it is true.

kirkyg

 

[FallenPhoenix]

Um the engine you have is an iron block. You have aluminum heads (except the non-PI heads )which have a proven track record in the performance realm. You also wont have to worry as much about headgaskets with the new ohc engines. Imo the newer engines are even more reliable than the 5.0L. I know its hard to find something 'new' thats built as well as an older product rigidity wise but in some cases it is true.

kirkyg

The non-PI heads were iron?

 

[bdcardinal]

all 4.6 heads are aluminum. PI, NPI, and 4v. the NPI heads on my current GM are aluminum, and the heads on my 92 were aluminum.

 

[Back2Mustangs]

I know its hard to find something 'new' thats built as well as an older product rigidity wise but in some cases it is true.

kirkyg

Well, I'm about to find out. I'll probably be buying this car in the morning. It seems to be mechanicly sound for the 144K miles it has. Car is much cleaner than I would ever expect for that kind of mileage too. PI heads and intake from a 99GT are coming with the car, and aftermarket cams as well. Don't know what the cams are yet though.