Death of a GT-40 Long block
(skip the story. I want PICTURES!!)
I purchased a new GT-40 long block in September 1993 for my 86 Mustang to replace the old worn out original engine. Since then, its been thru about 25+ track events of an average of 180 miles each. Oil changes have been before every event. Total mileage is probably not more than 20k on the engine. The engine had an oil pump failure in Nov 98, which was repaired and new rod bearings installed. No damage was caused by the failure (rod bearings looked good, but were replaced because I was there.)
Last November 99 I was out running at Summit Point. After warm up I was running hard laps on the new pavement in the instructors group Saturday morning. Coming up out of turn 9 just the before the bridge, at the shift point (about 6000 RPM and about 90ish) the engine locked up without warning, throwing the transmission out of gear. I was able to get into the pits, but the engine was dead. Knowing that the symptoms were not good, it went on the trailer for repair later.
I pulled the spark plugs and the valve covers. #4 plug was beat to death, and the #4 exhaust spring was fully extended, held in place only by the rocker. Not a good sign.
I drained the oil preparing for engine removal, and I got a cup or two of coolant out of the pan before the oil. humm,,,not a good sign.
I got the engine out and started to remove the pan. There I found dents in the side of the pan, and the dents were holding the pan bolts in-place. I had to smack the dents back in so to get the bolts to rotate. As I did so, I heard "rattling" in the pan. NOT a good sign at all.
I got the pan and the windage tray off the engine. What a mess. I have "rocks" of aluminum in the pan, a rod sitting on the windage tray, and all sorts of bits and pieces that once were attached to each other all over the place. so the damage is as follows...
Cylinders 1, 2, 5, & 6 are intact.
Cylinder 3 - the rod is twisted but intact. the bottom of the cylinder wall is broken
Cylinder 4 - the piston is missing. Not really missing, but it isn't where it is supposed to be. It's in the pan I think those "rocks" are what are left of it. The exhaust valve head is broken off at the stem (you can look up and see it missing). Probably in the pan. Cylinder wall broke at bottom. Rod still attached with wrist pin installed. Looks useable (right....)
Cylinder 7 - the piston is sheared in two at the wrist pin, with the upper half still in the upper cylinder. I guess the bottom half is in the pan.. The connecting rod broke at the big end. One bolt is intact (but broke off with a piece of the rod) and the other side of the rod and cap look pretty good, but the bolt is snapped. that rod was sitting on top of the windage tray.
Cylinder 8 - the bottom of the cylinder wall is broken.
Crankshaft - scarred where the #7 was thrashing around.
What came first? did the valve snap causing the #4 to destruct taking the #7 with it? or did the #7 rod bolt break causing subsequent damage to the #4 ?
I believe the valve broke, causing the destruction of the #4 piston. Those parts bounced around and jammed the #7 piston on a downstroke causing the rod big end to stretch breaking the connecting rod bolt, and ripping the bottom out of the piston. That rod came free and ended up on the tray.
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