Car 99 Engine Postmortem
Following the failure of the engine, it exhibited a complete lack of compression. This is strongly indicative of either a broken connecting rod, a blown out piston, or a seized valve. In addition, when turned over the engine produced a distinct clanking sound, more specifically suggesting a broken connecting rod as the culprit.
Upon primary inspection of the engine following its removal from the vehicle, it was discovered that a large hole had in fact been punched through the side of the crankcase. It was now certain that the connecting rod had failed, and the tear down procedure was modified to more directly target that component.
The crankcase was opened, and it was immediately determined that the connecting rod had in fact failed, as was evident from the collection of shrapnel left in the bottom of the case.
The piston was still in the cylinder, and the end of the connecting rod which had snapped off was still attached.
Here is an internal view of the hole in the crankcase.
A close up of the remains of the connecting rod.
The journal bearing on the crankshaft which once carried the connecting rod end. It is suspected that, due to lack of lubrication, this contact point seized, inducing a moment on the connecting rod of such a magnitude as to snap it in half. The system then continued to rotate, causing the now rigidly fixed connecting rod segment on the crank shaft to be driven into the side of the crankcase. When this happened, the wall of the crankcase was breached creating the hole seen above, and the remainder of the lower connecting rod section was shattered resulting in the debris found in the crankcase.
The cylinder head was then removed, and the piston and cylinder were inspected. The piston was found to move freely within the cylinder, supporting the theory that it was a seized journal bearing, and not some other malfunction such as a seized piston, which caused the connecting rod to fail.
The valve system was inspected, and found to be free of any easily discernible problems.
The piston was easily removed from the cylinder.
Here we see a close up of the upper portion of the connecting rod, still attached to the piston pin and able to freely rotate.
Connecting rod salad with light (too light) motor oil dressing .
The journal surface of the crankshaft was badly galled.
The lower portion of the connecting rod was shattered into several large pieces, and a number of smaller pieces, with a large amount of splinters and filings. It was pieced together as well as was possible to provide an idea of what it used to look like.
In summary, this engine has been destroyed, and with the damage to the crankcase casting, there is no immediately apparent method by which it could be restored.
I welcome any questions, comments, or concerns.