Keith Browning Posted October 6, 2005 Share Posted October 6, 2005 I discovered something in an engine I disassembled today that I consider a little strange. The piston in cylinder #7 developed a small crack about 3/4 of an inch inside the the bowl in the top of the piston. It progressed into a pea-sized hole as combustion heat began burning away at the metal. It actually looked like someone took an acetylene torch with a cutting tip to it. Nice and clean too. No damage to the head or cylinder walls either. I thought I would mention it just for interest. I have never seen this type of isolated failure on a 7.3L. Has anyone else??? When I get this completely apart and cleaned I'll photograph and post it. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 10, 2005 Author Share Posted October 10, 2005 Well I finally removed the piston and got a good look at it. It's more than a little crack and a small hole. The piston is almost cracked in half and by looking at the carbon on it it's been like this for a while. I am shocked that it lasted without coming completely apart. Believe it or not, there is no related damage at all! I have this piston sitting in a dunk tank to remove the carbon to get a better look at it. Quote Link to comment Share on other sites More sharing options...
Hayapower Posted October 11, 2005 Share Posted October 11, 2005 I had one a while ago that was being lit off consistently with ether in the AM's.. Denied of course, but finally a confession! The glow system was toast, and the BIG BANG finally took a 1/4-1/2" wide section of the rings, lands, and a hunk of the side of the piston on down into the pan.. Odd part was that the top of the piston looked 'almost' normal with a very minor, almost unnoticeable, OD distortion topside/crown.. Some cracking down lower as well, but no damage to the bore! Even after being run for some miles in it's condition, only some trace wear pattern, 'no' scoring, and the bore spec. was good as was the rod/s.. The other seven pistons were fine.. But it looked somewhat as you stated, melted away, like a torch was used to cut away a portion of the piston.. Intense heat and pressure at work /forums/images/%%GRAEMLIN_URL%%/smile.gif Quote Link to comment Share on other sites More sharing options...
Torqued_Up Posted October 15, 2005 Share Posted October 15, 2005 I'll tell ya, I have seen almost no base engine failures with the 7.3 either and as time goes on I get more and more impressed. The only failures I saw were customer caused. Saw a few seized valves and broken rockers and bent push rods but other than that nothing. These engines also seem to hold up to upgrading very well from what I have seen. Quote Link to comment Share on other sites More sharing options...
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