What is the bore and stroke of the 4.6 and 5.4 engines?

I ran a search but found nothing.

 

The 4.6 is 3.55 (bore) x 3.54 (stroke) and the 5.4 is 3.55 (bore) x 4.16 (stroke). Take care.

[This message has been edited by Steven_B (edited 06-02-2000).]

 

Thanks Steven.

Sure have little pistons as compared to the stroke. A 3.54 stroke is more inline with a 350 engine stroke. I bet our rings/cylinders wear out much quicker than the shorter stroke 302 engines due to more distance traveled per revolution. And the 5.4, no wonder they have piston slap.

 

Those figures alone shouldn't have any smoking gun as to piston slap.

But...

...if the piston (or skirt) is shorter on the 5.4 -- there's a real likely suspect!

I've been reading this board since first getting my '97 -- and have yet to read one good explanation of what is causing the infamous piston slap -- much less what was supposedly changed to fix it.

My experience with piston slap is limited to a very few engines (and I used to build them for a living) where piston to bore clearances were either intentionally or unintentionally wide (on the order of .010 inch) -- or where very short pistons running at very high torque low rpm modes ended up rocking back and forth thereby wearing into the skirt or bore -- probably due to poor ignition causing either knock/ping and exacerbating the problem by pushing down on the piston in an un-planned manner.

I'd hate to hear someone parrot'ng back this scenario and thereby making it gospel for the 5.4 -- but I would sure love to hear it from someone in the know.

Does it cause you to scratch your head why Ford is grabbing up all of those supposed-slappy engines? Is there something inside that they don't want anyone to see?


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Y2K™

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

I always thought that a longer stroke yielded higher torque, if you kept total cubic inches the same.

 

Grandpa,

Long stroke does tend to yield more torque with a given engine but there are other factors contributing to torque as well. Cam duration and lift. Usually shorter duration cams give more torque at lower rpm while longer duration cams give more torque higher up. With a given cam advancing the cam brings torque down to a lower rpm. And by retarding the cam causes the torque peak to occur at a higher engine speed. More valve lift, within a given head design, produces more torque but at the expense of valve train life. High lifts tend to wear out the valve train sooner, mostly due to higher spring loads required. Also important is plenum design. Longer runners tend to give more torque but less high rpm hp and torque. Compression ratio is a factor. However, the higher the compression ratio the higher the octane required. Exhaust design is a factor, mostly at high rpm but can increase across the rpm range if designed correctly. Everything is a tradeoff or compromise. This is why all out racing engines don't last very long and require high octane fuels. The truck manufacturers design trucks for general use and this is where we truck fanatics start to modify. We love to tailor our trucks to our needs and likes.

 

Coincident with longer stroke, longer connecting rods help in torque, since the lessened angle at the wrist pin reduces the opportunity for piston skirt wear (did somebody say McPiston Slap?) and transfers more leverage to the crank. The longer the better until the rods become either too heavy or too flexible.

Stroking an engine without changing the deck height usually means shorter skirts on the piston, increased angles on the connecting rod, increased wear on the pistons, and higher piston speeds than accompany longer rods.

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Y2K™

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Y2K,

Good point. Rod length is another factor of torque I forgot about. In the 302 engines they often increase the rod length by raising the pin height in the piston.

 

Larry: I just gotta get a set of Ford manuals -- I can't stand not knowing what's inside any more (do you suppose I'm going to have to sell the farm to pay for one?). It sounds like you've been in a couple of engines in your time, too.

I called a sister division to talk about the xfer case -- only to find out that it and the axles are Ford built -- not Dana.

I've spend hours searching the web using several search engines -- and I cannot find anything about the internals of these engines or the xfer cases.

I suppose I could stop by the local dealership and look at their manuals -- but I get ill even thinking of stepping foot in the door.

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Y2K™

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Y2K,

If you ever find out the fix for the 5.4 I would be very interested. I would think they decreased the piston/bore clearance and lengthened the skirt but only a guess. Let's tear down somebodies engine before and after the fix. I have a set of dial calibers, depth miks, intrimiks, a comparitor, dial indicators, a surface plate, telescoping gages and spring dividers. What will we need? LOL!

 

Larry, I'm with you!

We could put two 4.6l pistons in holes 1 and 2, some 1997 5.4l pistons in holse 3 and 4, some Y2K pistons in holes 5 and 6, and some lightning pistons in holes 7 and 8.

We'd add strain and vibration gages to the water-side of the bores so we could listen and chart the impact of skirt movement against the bores.

On the opposite sides, we'd install video cameras to watch the piston skirts movement -- to visually track any scratching which could occur from the skirt wear study.

On the heads, we could install knock sensors in each squench area of the combustion chamber so that any non-scheduled flame propagation could be detected.

Perhaps even infrared sensors could be added too, so we could actually map the flame propagation.

Despite the fact that bearing issues are not suspect, we should probably strain-gage the main bearing journals -- so that we can ensure that no out-of-synch sound propagation by way of the connecting rods is detected -- while this won't tell us anything of value, it is the easiest to wire, since there's no rotation of the bearing journals -- and good slip-rings are expensive as all get-out.

We should drill and thread into the cylinder bores at the piston skirt area, so that we can remotely control (by way of motorized flex rod) depth gages to that we can measure side-wall clearance when the engines get shut off. If we want, we could forget the gage part and merely put a ball on the end of the threaded shaft -- since then we could just turn in the shaft into the side of the piston skirt and thereby remotely take up any piston skirt clearance -- thereby automatically adjusting the piston-to-wall clearance -- thereby eliminating any chance for slap.

Hmmm. Come to think of it, we could just spring load a roller bearing on the skirt-side of the piston -- and automatically eliminate piston slap completely.

Where's the number for those patent guys that I see during the Movies-for-Guys-who-like-movies late-night show?

Now, all we need is an engine donor!



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Y2K™

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Y2K,

I got a better idea yet. Buy a Chevy truck! That new LS1 engine is one powerful engine. I rode in a 4.8 and it feels like it has 100 more hp than my 4.6 Ford.

 

Slap yourself, Larry!

What are U thinkin?

I think I'll go and join the Chevy board and post a lot of problems (heh heh).