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Core Corner

The 4.6L and 5.4L Ford engines change more rapidly than a speeding bullet, and continue to evolve into more complex mysteries than a Stephen King novel. Any of you who have tried to sort out this enigma know exactly what I am talking about. Careers will be made or broken over the 4.6L and 5.4L Ford engine arrangement variations.

I liken it to multiple-choice exams back in my high school days, the ones that I prayed for when I forgot about, or just plain didn’t study for, a test. Well, we are going to look at the crankshafts of these Ford engines and find the choices to be very similar to those high school exams. Our choices will be: A) Romeo; B) Windsor; C) 6-bolt flange; D) 8-bolt flange; and last but not least, that possible trick answer; E) All of the above.

Let’s get right to the pictures and see if we can get a feel for how many differences we really do have. You’ll see five different crankshafts in the photo (right), identified by letters A through E.

Letters A and B are pretty simple: A is the original steel 5.4L crankshaft (c/n F75-IE, F75-E) beginning in 1997, and has bullnose rounded edges on both leading and trailing edges of the counterweights. Produced at the Windsor plant, the 5.4L has an 8-bolt flywheel flange. Letter B is the cast 5.4L crankshaft (c/n XL3E BA) and it came in all 1999 applications including the DOHC Navigator. According to the parts information, the only application that still retained the steel forging was the F150 Lightning supercharged engine. The steel crankshaft, however, will interchange for all 5.4L applications.

Now we move on to the 4.6L crankshafts. We’re going to skip past C and D for a moment and go directly to E. Letter E is the 4.6L DOHC Mustang Cobra steel crankshaft (c/n F6TE-CE). Notice the additional two counterweights, one on each side of the center main journal. This crankshaft is also an 8-bolt flywheel flange with bullnose counter weights and was used from 1996 on up. This crankshaft is specific to the Cobra.

Let’s move to crankshafts C and D. Although they look nearly identical they are Romeo and Windsor 6- and 8-bolt crankshafts. These crankshafts have knife-edge counter weights as opposed to the bullnose.

Crank D is a 6-bolt flange crankshaft and the original release Romeo crankshaft 1991 through 1995 (c/n F1AE-AD). What you need to pay attention to, particularly if you try to use it in a Windsor block, is that the thickness of the first counterweight is .960-.977˝. Use of this crankshaft in a Windsor production block may result in interference with the rear of the block’s No. 1 main webbing. The worst part is that it may not even happen until the engine is running and start making a sound similar to a lifter noise. Paying close attention to the No. 1 counterweight clearance is always a good idea for all applications.

There is also a 6-bolt Windsor crankshaft from 1996 (c/n F65EBB-22D) that has a front counterweight thickness of .920˝-.940˝ and can actually be used in either a Romeo or Windsor production. In 1996, the Romeo engine also got a narrow front counterweight crankshaft (c/n F65EBB-39D), which is a 6-bolt flange as well and could actually interchange for the Windsor.

Crankshaft D is an eight-bolt flange and has the narrow front counterweight (c/n F65EBB-44D) and is traditionally considered a Windsor crankshaft and should be in all Mustang SOHC applications. After that it becomes a crapshoot. We have seen 6- and 8- bolt crankshafts in engine production runs that have the same broadcast code.

The 8-bolt flange crankshaft is also the service replacement crankshaft so if you had a 6-bolt you need to change the flex plate. It is considered best practices to get that information from the customer prior to shipping an engine if possible. If an engine is shipped with the incorrect bolt flange the solution is simple, replace the flex plate and you’re done.

Lastly, it has been our experience that standard transmission applications after 1996 are all 8-bolt. So all things being equal, the 8-bolt cranks can actually be letter E of that high school test – "All of the above."

Special thanks to Larry Eriksson, Crankshaft Rebuilders, and Chip Helderman, Jasper Engines for their assistance.