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Discussion Starter · #1 ·
...something goes BOOM?
It's been a while, and I missed the board changeover, but I like the new look. :D

Anyway, I've been thinking about my '95 LX again, and just how far one can push the stock block before it's time to swap in a '99GT. Any ideas? Bear in mind, this includes changing the heads, rods, pistons, etc. I'm more concerned about the actual block itself. BTW, Bird in question has 86k+ on it right now.
 

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I've read...

that a lot of people (with better tires, better driveshaft, and chip) have hit up to 120-130, and their car still runs fine. Whether they are flat out lying, optomistic (unless it's a SC or recalibrated 140 speedo, they are guessing), or true is questionable. Anyone have a TRUTHFUL answer?

Pat
 

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John Langton has his bird up to 211rwhp, and still on the stock block. Stock 4.6Ls are known to last to 200K miles.
 

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I thought he was talkin bout speed.

Anyways, what about people with the Allen. They push over 280 at the wheels (most do), and I don't think they change the block (althought the probably do).

Pat
 

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Well....it all depends

Though the enignes them selves are built to the same standards, they will all have different flaws (e.g. something will break on mn12 #A that doesnt break under the same stress on MN12 #B).

From what I have gathered, the rods are the weak link in all mod motors. Granted you can put Hi-Po heads and a blower on top, but it's just a matter of time before something breaks. Of course then again, you could build up the top and the bottom never blow. What breaks the bottom end of an engine is one's desire to make more and more power. I personally believe if you hit close to the 300hp mark or over and still haven't replaced the internals, then you are asking for trouble.

Personally I would be comfortable with an Allen Roots, and a set of P&P'd NPI heads on top. I believe the internals would hold up as long as the car isn't driven to the limit. <<<< But DO NOT TAKE THAT TO THE BANK. That's what I'm personally willing to try.

It's really what you're willing to risk. By keeping the Engine N/A you shouldn't worry about the internals. But when you decided a power adder (Nitrous/SC/ [Turbo < has that even been tried yet?]) is you're next mod you had better make sure you can handle things if the car would go BOOM!

You should only limit your power to what YOU think you're comfortable running. What everyone else says is there own opinion, and from their personal experiences. If your MN12 is your only car, I would NOT put the NAWWS or a blower of any sort on top without having a back up plan in case the worst would happen.

My 2 and a half pennies :D
 

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Re: Well....it all depends

Stephen C said:
I personally believe if you hit close to the 300hp mark or over and still haven't replaced the internals, then you are asking for trouble.
300rwhp. :D

Stephen C said:
Personally I would be comfortable with an Allen Roots, and a set of P&P'd NPI heads on top. I believe the internals would hold up as long as the car isn't driven to the limit.
a set of PI heads will raise compression to 10.4:1 and running 6psi of boost, that gives an effective compression ratio of 14.64 This all means one thing...BOOM


EDIT:

Noe S. said:
He said "NPI" heads, not "PI" with an Allen Roots kit.
Good Call.
 

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Re: Re: Well....it all depends

GreenBird said:
Oops. Yeah when I said 300hp I was referring to rear wheel horse power, I just forgot the 'rw.' :p


Cheers
 

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Oh boy...

Just a few corrections here...

First, a 4.6L engine that is naturally aspirated can break a piston ring land from detonation. I know this, I have seen it! 1 psi of boost is enough to damage the internals on our engines. If you think it's the tune, you have a lot to learn. Yes a good tune helps, but the damn cylinder pressure is still there, isn't it? Yes. Intercoolers help, but they won't protect you either.


wannabesvt,

I have the stock 4.6L long block in my '95 T-Bird. So does EECDOC. We both runs 12's with our AED kits and make well over 300 RWHP.

You do not have to change the block.

Green bird,

You said "a set of PI heads will raise compression to 10.4:1 and running 6psi of boost, that gives an effective compression ratio of 14.64 This all means one thing...BOOM"

No, a blower NEVER changes the compression ratio of any engine. Period. It changes the air charge compression ratio. The C/R was 9.0:1 before the AED kit, it will be after. Without intercooling the air charge compression ratio would be 12.67:1 @ 6-psi. 8-psi gives you 13.89:1, again without intercooling.

I agree with you about PI heads on a non-PI block and a blower. That is a recipe for disaster since the cylinder pressures will skyrocket. Either the pistons will give up or the rods will. Or both. You really want 8.5:1-9.0:1 C/R with a blower. Anything higher is asking for a headache.

Blackjack_21,

You'll need forged internals to deal with a blower safely. Then you'll need a knock sensor, an ACT sensor and a very good tune on the dyno with a wide band 02. That will get you the power and longevity/durability you desire.

I run a stock '00 GT long block in my '95 T-Bird. It runs a fair amount of boost on the stock parts and while it won't last forever, it should hold up to a lot of abuse. Go lean though and you'll be in trouble.

A-Train
 

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Re: Oh boy...

A-Train said:
Just a few corrections here...

Green bird,

You said "a set of PI heads will raise compression to 10.4:1 and running 6psi of boost, that gives an effective compression ratio of 14.64 This all means one thing...BOOM"

No, a blower NEVER changes the compression ratio of any engine. Period. It changes the air charge compression ratio. The C/R was 9.0:1 before the AED kit, it will be after. Without intercooling the air charge compression ratio would be 12.67:1 @ 6-psi. 8-psi gives you 13.89:1, again without intercooling.
I agree. I suppose my use of puncuation was in error. I meant PI heads raise compression to 10.4:1. Adding a blower pushing 6psi will raise effective compression to 14.64. I would define effective compression as a synonym of your term, "air charge compression ratio".

P.S. Someone ;) should change A-train's status to something much more suitable.
 

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push?

Hey guys, you're all on the right track, but then again I think that we got side tracked too. The bottom line is that the 4.6 stock engine can go a very long time. In a Crown Vic taxi, the 4.6 has logged over 300,000 miles without nary an engine burp.

From my own driver's seat I've logged 132,000 and the engine is sound. The original tranny is out and a 1999 version is in. At 74,000 the '94 went boom! the '99 [knock on wood...like the top-o-me-head...has been trouble free after making the Jerry "mild mods".

I talk to the local Ford dealer mechs at the bars, and they tell me that they have seen 250, 300, even 350 THOUSAND miles on the base 4.6...but none of them can recall a T-Bird with as many miles as mine.

I think what you all have said before is very true: depending on the mods you make and the way you drive, you can push the stress-limit on any component.
 

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Just to pipe in and stand up for these motors, I have over 170,000 miles on mine and go over 140 and 150 mph with no problem. I'm not all stock, but the motor it self is.
I will be posting proof of this later.
 

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[email protected] Once. I ran over 300hp with a vortech and a fmu setup for 30,000 miles. It was pig rich but safe. As said detonation is the death of the motor. If you get around the 450hp rear wheel the stock rods have a tendencey to exit the side of the block.

bc
 

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Yeah and...

Blake was using a little nitrous for an intercooling effect on that run. Things just aren't designed to take boost on the stock 4.6L. The extreme cylinder pressures and extra heat will destory the weak hyperpathetic pistons and skinny rods. Blake is right, the rods will exit the block sooner than that.

That's why the '03 Cobra and '99-'02 Lightnings use forged pistons, forged rods, forged crankshafts, ACT's and a knock sensor.

A-Train
 

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I guess some people believe what they read on the internet. I posted this on the MTC board. I used a pass I made before my new motor was tuned. The first line is the weather on the infamous day it was actually colder than 44 more like 39.
My old motor made [email protected] wheels hot. It runs about 3 mph faster stone cold. I also had the car weight to 3750 with me in it. If you look at the density altitude a true mine shaft day combined with the fastest strip in the country. I have heard it look at the smoke its got to be sprayed. Next time your at a dyno tune and a car detonates real bad what do you see alot of smoke. All the NOS talk was started by one person who in most cases is right but this one was dead wrong. He never has got over it:). I snatched the title from him and he never could get it back after so many gallant attempts and motors:) He finnaly threw in the towel:) I'am the king!!

Blake
The fastest MN12

44.60° F / 7.0° C 35.60° F / 2.0° C 71% 30.54 in / 1034.0 hPa 10.0 miles / 16.1 kilometers 13.8 mph / 22.2 km/h


PaiN's Weather Station
Original Conditions: Temp: 65 Humidity: 90 Barometric Pressure: 30.10 Density Altitude: 389 Original results: ET: 12.3 MPH: 110
Submitted conditions: Temperature: 44.6 Humidity: 71 Barometric pressure: 30.54 Density Altitude: -1,977 Corrected results: (What you would have run under the submitted conditions) Corrected ET =11.98 Corrected MPH =113.01

http://xs-fx.com/da/ws.htm


http://www.wunderground.com/history/airport/KEFD/2001/2/17/DailyHistory.html
 

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The original question was how much can the block hold.
On a '95 block with replaced everything I would expect it could handle 500 hp, but not all the time.
I think you will still fail something else before a block , bearing or cam chain or something else before the block is an issue. Blocks usually fail due to something else , rod lets go or bearing seizes.

I am under the impression that the PI block is stouter, but that may not be true.
For the money, the block should be the least of your worries.

rm
 

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Please corrected me if I'm wrong; but if you are only talking about the blocks on the 4.6 then I agree with RM....Ford (this is where you can correct me if I'm wrong) used the same block for all SOHC 4.6's, which I've seen many of these (stock) in other cars and trucks for 250-350rwhp. Don't worry about the block....it's all about the lifters, rods, and springs.
 

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WolfgangNC said:
Please corrected me if I'm wrong; but if you are only talking about the blocks on the 4.6 then I agree with RM....Ford (this is where you can correct me if I'm wrong) used the same block for all SOHC 4.6's, which I've seen many of these (stock) in other cars and trucks for 250-350rwhp. Don't worry about the block....it's all about the lifters, rods, and springs.
The SOHC and DOHC blocks are the same. the romeo and windsor blocks are different.
 

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Discussion Starter · #19 ·
Okay, I get the idea that the actual block is the least of my worries...
If I want to get 300rwhp, I need forged everything, PI heads, and a blower, or NOS. I don't like the NOS idea, only becuase I've never used it before. For the money, though, I get the idea that I should get a '99 GT motor and build it up instead of building up my current block, putting on PI heads, forged internals, etc..
Add to that a T-45, since I wanna shift the car myself, at least 3.55 Trac Loc gears, good tires and an upgraded suspension/sway bar setup, and you're talking some serious cash.
Damn, I need to sell some of my internal organs or something... :D
 

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No they aren't...

Blocks only?

Well then let's talk about them. There is a bastard block for the 4.6L in '91 that mates to an AOD. Stay away from that block. The '92-'98 ROMEO 2V cast-iron blocks are said to be adequate for most applications with the right parts. They have a 4-bolt main on most while the older blocks did not have the jack screws on the rear main.

The DOHC block is a 6-bolt main and it's aluminum with steel cylinder sleeves. It's 6-bolt for a reason.

The '99-'00 GT blocks are WINDSOR. There are some trucks and Crown Vic's that had WINDSOR blocks from '96-'00 but it's easier to identify a Mustang application. The WINDSOR has a much better oiling system than the older ROMEO blocks. The WINDSOR has more webbing that makes it slightly more ridged than the older ROMEO blocks. The WINDSOR blocks have a 4-bolt main with dowels to spread the load. Its close to a 6-bolt main in that respect. The WINDSOR block is a better starting foundation for a forged build-up.

The '03 Cobra uses a ROMEO CAST IRON block.





This is a photo of a 2000 Mustang GT WINDSOR engine. You can clearly see the two caps screws on the mains and the dowels (2) next to them. Of course on the side of the block there are the side jack screws (2) that you can't see. Good stuff.


How much can the block handle? Don't know, but some Cobra guys making 600 RWHP have split the aluminum (cracked it) block. Others have distorted the main caps. The cast iron block on either application can still have a rod exit the side. I think Kdanner proved the WINDSOR block is no stronger in that respect.

A-Train
 
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