2011 & Up Coyote 5.0 Piston / Cylinder Failure





We have seen many failed 5.0 engines (about 12-15) since the summer of 2010 and it is now 2012 so we have 2 years of field experience.

We have not seen an isolated “Number 8” cylinder related failure until this week, 7/23/2012.
We have seen extensive piston failures similar to this on the left bank, more common on cylinders # 6 & 7 which is common to all Ford V8 4V regardless of model year, but have not seen cylinder problems on the left bank until the 2011 5.0 model year. All Modular 4V engines with piston failure have the failure on the inboard (intake) side of the engine. We have also routinely seen most heat issues on the left bank of all Modular 4V regardless of model years, which would require detailed study of the coolant path of both banks to determine the issues.
Not having access to the actual cylinder # 8 complaint engines we believe this may have a common contributing factor.
The engine I speak of with the cylinder 8 problem will not lend itself to photos other than the piston, the catastrophic failures we recorded are the exact same phenomena as the more subtle failure in our “number 8” failure of a distorted bore (.0005”-.0007”) in the exact same area causing a loss of ring seal and subsequent overheating of the piston by combustion gases.
In addition, the moly fill of the top ring has been melted away by the heat; the top ring in the other 2/3 of the radial area is normal.

I also included below an excerpt of correspondence to Ford Racing in late December 2011 and another copy of this correspondence sent mid January 2012.
I have not received any reply or feedback regarding my observations so I thought it fair to say there is not much interest and as there is intense interest here, I thought I would publish it in this forum.

To Ford Racing ---------
……………………. I attached a photo, “Cylinder 2011 Fracture”, of the “bent” cylinder syndrome where the bending moment went to yield.
As you can see the inboard portion of the cylinder and inboard portion of the cylinder case fractured; obviously due to abnormal pressure.
The point I want to make with this photo is we have 3 of these engines with this fracture failure, all on inboard cylinders (# 2, 3, 6, or 7) indiscriminately.
The discussion and my concern is the less severe failure which is a bending/distortion of the cylinder in exactly the same local area of the photo.
I have 6-8 blocks here that show the “bend” at the top of the cylinder from .002”-.006” gradually tapering off in a triangular fashion, as seen in the photo, to the mean bore diameter about .750” – 1.000” below the deck.
This failure is common only to the 2011-2012 platform and is due to the coolant core hole at the deck in this locality being modified from the 4.6-5.4 designs by removing the strut that separated the core hole into a single elongated hole, as exhibited in the attached photos; “4.6 Deck” – “2011 Deck”. …………………………………………..

Regards, Michael Rauscher - L&M Engines

EDIT - This cylinder distortion has been seen on OE configured engines as well as supercharged/turbocharged engines. Cylinder breakage has been seen on supercharged/turbocharged engines. The photo of the broken cylinder is a 26 lb turbocharged design.