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Mon Oct 22, 2012 6:52 pm
mrdibs wrote:So, can I just replace the piston?
You could and everything would probably be fine. But if this were my engine I would freshen it up. Depending on measurements, minimum would be rering, lap valves, new rod and main bearings.
Mon Oct 22, 2012 7:27 pm
Just out of curiosity, were you able to determine what the debris was composed of?
Mon Oct 22, 2012 7:37 pm
lazyuniondriver wrote:Just out of curiosity, were you able to determine what the debris was composed of?
Wondering that myself, why would a new built engine have debris like this ?
Mon Oct 22, 2012 7:38 pm
Check the head for damage. What ever knocked a hole in the piston probably did just as much damage to the head.
What is the history on this engine?
Tue Oct 23, 2012 8:30 am
I didn't find any damage to the head. Debris seemed to be just part of the piston. I did not replaced the pistons and one of them was seized when I started. Could be I damaged it while freeing and it just now caught up with me. I guess the debris was what got it stuck, because once the head was off, I was able to turn the motor by hand. I guess the good news is that this all happened on a cold engine at idle. Otherwise I'd certainly have cracked the head or worse. I'm too poor this winter for 4 new pistons, so I'm going to replace the one for now and do the rest in the Spring I guess.
Tue Oct 23, 2012 1:57 pm
There was probably enough debris piled up to stop the piston just shy of TDC. That's why you couldn't budge it until the head was off.
Wed Oct 31, 2012 11:41 am
Well I found a used piston and installed it during Sandy. Engine running again, but it does puff a bit of smoke when I goose it. Probably more than usual, but I need to work the tractor before the snow flies so it is what it is. Visual inspection of cylinders revealed no damage. Head is ok and I used a new gasket. To the horror of some, I'm sure, I transplanted the rings which were only one season old and seemed fine. But I did use a new rod bearing. I'm probably due for a bore and new valves, but I'm tempted just to run it till it won't, then worry about it. Thanks for the help everyone. How I ended up with a hole in my piston remains an unsolved mystery. Tonight I plan to pull the plugs before starting again, just to make sure I'm not getting water in the cylinders.
Thu Nov 01, 2012 9:03 am
What did the spark plug look like in that cylinder?
Thu Nov 01, 2012 3:59 pm
skylor60 wrote:What did the spark plug look like in that cylinder?
Same as the others. A little black - gap was fine. Carbon buildup was minimal. The engine was seized when I originally started working on it many years ago. Very possible I damaged the piston while freeing it up, but got away with it for almost an entire season. Really it should have been #4 because that's the one I had to smack the hardest, but I probably hit #3 too. Years of mistreatement and overheating may have contributed to weakness in the metal. If I find a new set of pistons I can afford, I'll replace them all - maybe bore it too.
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