Modular 4.6,5.4 and 6.8L Engine Info.
CRANK
The most common cranks for 4.6L engines are the nodular cast iron units.
They come in both 6 & 8 bolt flywheel configurations.
The 2-valve Windsor engines use both a 6 & 8 bolt flywheel, the Romeo engines use 6
The only factory forged cranks available for the 4.6L DOHC engines are installed in the Cobra.
These cranks are manufactured by Gertach in Germany for Ford
The cranks in the 5.4L DOHC and SOHC engines are also available in cast or forged.
Most of the cranks are forged, but not all
The only way to know for certain is to look at the parting line.
Thick line for forged, thin line for cast
Note that just because a crank has 8 bolts does not mean that it is forged
RODS
With the exception of the 2000 Cobra R (Carillo) and the 2003-2004 Cobra's (Manley H-beam)
All modular engines have come with sinter forged powdered metal connecting rods
The 4.6L SOHC passenger car engines have the weakest rods.
the Windsor (or Triton) engines use a larger connecting rod that is stronger than the passenger car engines.
The 4.6L DOHC engines use the same rods as are used in the Windsor's.
The strongest factory style rods to date are the rods used in the supercharged 5.4L lightning.
These rods have a larger big end than the standard modular rods.
4.6L Rod length = 5.93"
5.4L Rod length = 6.65"
PISTONS
The pistons used in modular engines are all of the hypereutectic style,with a few exceptions.
These exceptions are the supercharged Lightning and Cobra.
Most of the pistons used in modular engines are dished.
Pistons are interchangeable between the DOHC and SOHC, 6.8L, 5.4L & 4.6L engines.
But you will need to check piston to valve clearance when doing so.
SOHC 4.6L, 5.4L,and 6.8L
1991 thru 1998 ----- 10.49cc dish
1999 thru 2000 ----- 18.10cc dish
2001 thru 2004 ----- 15.80cc dish
DOHC 4.6L
1993 thru 1998 ----- 2.66cc dish
1999 thru 2002 ----- 4.54cc dish
DOHC 5.4L
1998 thru 2004 ---- Flattop
HEADS
Heads-------Combustion chamber volume/ Intake Valve/ Exhaust Valve
91-98NPI-------------------------52cc/43.69mm(1.752)/ 34mm(1.339)
99-02----------------------------44cc/43.69mm(1.752)/ 36mm(1.417)
FRPP-----------------------------51cc/ 46.74,,(1.840)/ 35.81mm(1.410)
HEAD FLOW
Stock Intake------Stock Exhaust------Ported Intake-----Ported Exhaust
Flow @ .50 Lift----flow @ .50 Lift------Flow @ .50 Lift----Flow @ .50 Lift
NPI---150CFM-------150CFM------------190CFM-----------170CFM
PI----165CFM-------150CFM------------220CFM-----------190CFM
FRPP--215CFM------150CFM------------235CFM-----------200CFM
COMPRESSION
DISH CC-----------1991-1996 NPI------1999-2004PI
Flatop----------------10:3:1--------------11:2:1
2.66cc---------------10:0:1--------------10:9:1
4.54cc---------------9:8:1---------------10:7:1
10.49cc--------------8:9:1---------------9:5:1
15.80cc--------------8:5:1---------------9:0:1
18.10cc--------------8:3:1---------------8:8:1
WINDSOR OR ROMEO?
The 4.6L SOHC and the 5.4L SOHC use the same basic heads.
The difference in these heads is not whether they were installed on a 5.4L or 4.6L,
but whether the engine was built in the Windsor plant or the Romeo plant.
The Windsor heads use 14 bolts for the valve covers while the Romeo engines use 11.
That is the easiest way to tell them apart but there are a lot of other differences.
The two heads share the same basic archetecture but thats about it.
FORCED INDUCTION/NITROUS
Truth about your Rods/Pistons
Truth is, Forced induction cars can run on factory pistons and produce good horsepower, the question is, for how long?
If you are building a forced induction engine you need to understand that the factory pistons do have their limitations and when you reach these limitations, it's not pretty.
Same goes for the Rods they are fine for use in mild performance applications.
If a blower, nitrous or turbo is in your future,and your looking for alot more then 400-425RWHP
You would be doing yourself a favor by upgrading your rods/pistons to forged steel.
NPI VS PI
These heads can be separated into pre-1999 non-performance improved (NPI) and post 1999 performance improved (PI).
If you have a set of pre-1999 heads and want to use them, understand that a fully ported set of these heads will perform a little better than a set of PI heads out of the box.
If your willing and capable of doing your own porting work you can build a strong SOHC engine with these heads,
just understand that these heads will never perform as well as a set of ported PI heads. Be very careful when porting these heads.
There is not much material to play with. This applies to all castings.
The post 1999 heads (PI) are excellent castings. These heads work well as is, but really respond to a
good port & polish job. After porting these heads can flow as well as the FRPP heads listed below.
For supercharged applications or hi-performance engines these heads are a good starting point. The moral of the story is: if you are looking to buy an engine, buy a 1999 or newer.
CRANK
The most common cranks for 4.6L engines are the nodular cast iron units.
They come in both 6 & 8 bolt flywheel configurations.
The 2-valve Windsor engines use both a 6 & 8 bolt flywheel, the Romeo engines use 6
The only factory forged cranks available for the 4.6L DOHC engines are installed in the Cobra.
These cranks are manufactured by Gertach in Germany for Ford
The cranks in the 5.4L DOHC and SOHC engines are also available in cast or forged.
Most of the cranks are forged, but not all
The only way to know for certain is to look at the parting line.
Thick line for forged, thin line for cast
Note that just because a crank has 8 bolts does not mean that it is forged
RODS
With the exception of the 2000 Cobra R (Carillo) and the 2003-2004 Cobra's (Manley H-beam)
All modular engines have come with sinter forged powdered metal connecting rods
The 4.6L SOHC passenger car engines have the weakest rods.
the Windsor (or Triton) engines use a larger connecting rod that is stronger than the passenger car engines.
The 4.6L DOHC engines use the same rods as are used in the Windsor's.
The strongest factory style rods to date are the rods used in the supercharged 5.4L lightning.
These rods have a larger big end than the standard modular rods.
4.6L Rod length = 5.93"
5.4L Rod length = 6.65"
PISTONS
The pistons used in modular engines are all of the hypereutectic style,with a few exceptions.
These exceptions are the supercharged Lightning and Cobra.
Most of the pistons used in modular engines are dished.
Pistons are interchangeable between the DOHC and SOHC, 6.8L, 5.4L & 4.6L engines.
But you will need to check piston to valve clearance when doing so.
SOHC 4.6L, 5.4L,and 6.8L
1991 thru 1998 ----- 10.49cc dish
1999 thru 2000 ----- 18.10cc dish
2001 thru 2004 ----- 15.80cc dish
DOHC 4.6L
1993 thru 1998 ----- 2.66cc dish
1999 thru 2002 ----- 4.54cc dish
DOHC 5.4L
1998 thru 2004 ---- Flattop
HEADS
Heads-------Combustion chamber volume/ Intake Valve/ Exhaust Valve
91-98NPI-------------------------52cc/43.69mm(1.752)/ 34mm(1.339)
99-02----------------------------44cc/43.69mm(1.752)/ 36mm(1.417)
FRPP-----------------------------51cc/ 46.74,,(1.840)/ 35.81mm(1.410)
HEAD FLOW
Stock Intake------Stock Exhaust------Ported Intake-----Ported Exhaust
Flow @ .50 Lift----flow @ .50 Lift------Flow @ .50 Lift----Flow @ .50 Lift
NPI---150CFM-------150CFM------------190CFM-----------170CFM
PI----165CFM-------150CFM------------220CFM-----------190CFM
FRPP--215CFM------150CFM------------235CFM-----------200CFM
COMPRESSION
DISH CC-----------1991-1996 NPI------1999-2004PI
Flatop----------------10:3:1--------------11:2:1
2.66cc---------------10:0:1--------------10:9:1
4.54cc---------------9:8:1---------------10:7:1
10.49cc--------------8:9:1---------------9:5:1
15.80cc--------------8:5:1---------------9:0:1
18.10cc--------------8:3:1---------------8:8:1
WINDSOR OR ROMEO?
The 4.6L SOHC and the 5.4L SOHC use the same basic heads.
The difference in these heads is not whether they were installed on a 5.4L or 4.6L,
but whether the engine was built in the Windsor plant or the Romeo plant.
The Windsor heads use 14 bolts for the valve covers while the Romeo engines use 11.
That is the easiest way to tell them apart but there are a lot of other differences.
The two heads share the same basic archetecture but thats about it.
FORCED INDUCTION/NITROUS
Truth about your Rods/Pistons
Truth is, Forced induction cars can run on factory pistons and produce good horsepower, the question is, for how long?
If you are building a forced induction engine you need to understand that the factory pistons do have their limitations and when you reach these limitations, it's not pretty.
Same goes for the Rods they are fine for use in mild performance applications.
If a blower, nitrous or turbo is in your future,and your looking for alot more then 400-425RWHP
You would be doing yourself a favor by upgrading your rods/pistons to forged steel.
NPI VS PI
These heads can be separated into pre-1999 non-performance improved (NPI) and post 1999 performance improved (PI).
If you have a set of pre-1999 heads and want to use them, understand that a fully ported set of these heads will perform a little better than a set of PI heads out of the box.
If your willing and capable of doing your own porting work you can build a strong SOHC engine with these heads,
just understand that these heads will never perform as well as a set of ported PI heads. Be very careful when porting these heads.
There is not much material to play with. This applies to all castings.
The post 1999 heads (PI) are excellent castings. These heads work well as is, but really respond to a
good port & polish job. After porting these heads can flow as well as the FRPP heads listed below.
For supercharged applications or hi-performance engines these heads are a good starting point. The moral of the story is: if you are looking to buy an engine, buy a 1999 or newer.
thanx. really good info in a nutshell.
