Got a call from a customer Sat afternoon telling me that the engine driving the air compressor on his rock drill had just blown the center part of the valve cover off. He said it made a fairely audible 'pop' when it happend and they immediately shut the engine down. The engine is a CAT 3054C which is basically a 4 cylinder CAT branded Perkins with a turbo, and the valve cover is a plastic composite of some kind.
I immediately suspeted the worst, that being a bent/stuck valve causing a pushrod to bend and get thrown, a broken rocker arm, etc, etc. Imagine my suprise when I got down to look at the machine and there was nothing wrong on the top end and the engine fired up and ran like a Swiss watch. We even went so far as to go ahead and load the compressor to make sure there was nothing wrong and beyond a bit of splash oil getting slobbered out of the broken valve cover everything was fine. There was no idication of the dip stick having moved from overpressurization of the crankcase, nor was the crankcase vent blocked in any way.
Now I could have understood the possibility of ether somehow getting into the crankcase, or gas vapors from flooding if it wasn't a diesel, and somehow getting ignited on startup. Thing is, it is a diesel, and this happened after they had been running and drilling for a good while. In other words there wasn't really any way for any kind of vapor to have gotten into the crankcase to ignite and even if it did what would have been the ignition source when everything is soaked in oil?
I've talked to a couple of other experienced mechanic friends since I got home yesterday evening and run this by them and so far we are all coming up empty as to a plausible cause for this to happen. The only thing the customer and I could think of would have been for someone to have stepped on it and cracked it, but where it's situated it would have been all but impossible for someone to have gotten their foot into that small of a space. Even then, if it were cracked, what would have made it go POP as forcibly as the customer said it did ???
Like I said myself and everyone I know are stumped and I'm just curious as to wether any of you guys had ever experienced anything like it. Especially as it pertains to a non-metal cover, and I say that because I know plastics can be stressed, etc, etc and snap with some force. There again this machine is somewhere around 6 or 7 years old so why wait until now to 'pop'??? Like I said nothing I, or anyone I know, can think of makes any sense at all as to why this happened.......... Any plausible ideas??????
I immediately suspeted the worst, that being a bent/stuck valve causing a pushrod to bend and get thrown, a broken rocker arm, etc, etc. Imagine my suprise when I got down to look at the machine and there was nothing wrong on the top end and the engine fired up and ran like a Swiss watch. We even went so far as to go ahead and load the compressor to make sure there was nothing wrong and beyond a bit of splash oil getting slobbered out of the broken valve cover everything was fine. There was no idication of the dip stick having moved from overpressurization of the crankcase, nor was the crankcase vent blocked in any way.
Now I could have understood the possibility of ether somehow getting into the crankcase, or gas vapors from flooding if it wasn't a diesel, and somehow getting ignited on startup. Thing is, it is a diesel, and this happened after they had been running and drilling for a good while. In other words there wasn't really any way for any kind of vapor to have gotten into the crankcase to ignite and even if it did what would have been the ignition source when everything is soaked in oil?
I've talked to a couple of other experienced mechanic friends since I got home yesterday evening and run this by them and so far we are all coming up empty as to a plausible cause for this to happen. The only thing the customer and I could think of would have been for someone to have stepped on it and cracked it, but where it's situated it would have been all but impossible for someone to have gotten their foot into that small of a space. Even then, if it were cracked, what would have made it go POP as forcibly as the customer said it did ???
Like I said myself and everyone I know are stumped and I'm just curious as to wether any of you guys had ever experienced anything like it. Especially as it pertains to a non-metal cover, and I say that because I know plastics can be stressed, etc, etc and snap with some force. There again this machine is somewhere around 6 or 7 years old so why wait until now to 'pop'??? Like I said nothing I, or anyone I know, can think of makes any sense at all as to why this happened.......... Any plausible ideas??????