Are the piston skirts non-existant because of long-stroke? Or because the engine is so short as to dictate that the crank counterweights are in the way? Back to that small bore-to-bore distance...

You are absolutely correct. The R&R on a head is a longer process. And the small distance bore-to-bore is a pain in the neck.

One thing, though, about the longe-stroke, the V10 would certainly not perform the same without it.

 

Lets start a new topic if we want to talk cevy vs ford piston slap. We are kinda hijacking the thread here.

 

"That's because the big block Chevy has a big bore diameter and pistons to go with those long rods."

Keep the subjects straight. Are you implying that the larger bores allow the Chevy to be hot rodded? Or are you trying to say that larger bores prevent piston slap???

Rod/stroke ratio is infinitely more important than bore size when discussing the engine's ability to rev. The piston slap issue is dead. It only affect a limited number of engines and it has LONG been resolved.

 

Its OHC vs OHV.

 

Last time I looked my 4.6L's and V10 were OHV ...

Didn't know I had a flat-head...

 

Sorry, OHC vs Pushrod is what is implied.

 

Piston slap in the 5.4L was still a problem in the '03 model year - but *supposedly* has finally been fixed in the new 3v version of the 5.4L. I hope it's fixed for real this time - my '02 was built after Ford supposedly "fixed" the problem a couple years ago, and it had piston slap so bad on cold mornings that it made the old diesel in my farm truck sound quiet by comparison. Ford knew piston slap was still a problem, and early press releases about the 3v version of the 5.4L actually mentioned that the pistons had been modified to reduce the slap.

However, I'll agree that GM has had a larger problem with piston slap than Ford...but both of them have had the problem.

LK

 

LK,
Remind me to never go to Vegas with you. You must be the most unlucky person in the world. You are the only person I have heard of since about '99 that has had any significant issue with the piston slap.

That being said, those issues have nothing to do with bore/stoke and certainly nothing to do with whether it is OHC or pushrod design.

 

Apparently you don't talk to many people with new Fords, or at least don't spend much time on the 5.4L or V10 forums.

There are actually quite a few people who have had this problem - both with the 5.4L V8 and with the V10 - and many of them have trucks that were the '00 model year or later. It's not really as rare as you might think - while I couldn't guess as the exact percentage, I've seen (and heard) a few other new Ford trucks with piston slap. When I had my truck in to the dealership for service, I had several people say that they'd seen this problem on quite a few of the new Ford trucks - to the point where Ford will no longer replace engines, but instead told the dealers to tell customers that the piston slap wouldn't cause any long-term damage (similar to what GM is doing).

Or, another way to think about it - if piston slap really wasn't a problem after '99, why would Ford go out of their way to mention that they'd finally fixed the problem on the 3v version in the '04 F150?

If you want more details than you'll ever need, there was a presentation given by Ford in 2001 that details the efforts to model the problem -

http://support.adams.com/kb/faq.asp?ID=kb9359.dasp

If you click on the PDF file on that page it will give you 20 different slides that were used in the presentation. If you read through it you'll find that Ford was still working on the problem in 2001 - after thay had supposedly "fixed" the piston slap.

However, you are correct that the piston slap problem has nothing to do with OHC engines vs. pushrod engines - I would have to say that short piston skirts are the primary cause.

LK