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youtube.com/5Tractorguy
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Discussion Starter #1
Made another attempt to fire up the Mutt tractor that I got last weekend. Had no compression so I tryed adjusting the valves, still nothing. Took the heard off again and had a look....Oh Boy.....

Some one had did a top end job on this 7.6hp engine. The head was decked and if you look closely, .020 over piston. Probably doesn't have much use on it. Unfortunatly someone forgot to put the wrist pin clips in and ran it like that until compression was lost and it wouldn't start:maddd::banghead3:banghead3. Made a nice pair of deep ware marks on each side of the jug. Too bad, would have been a nice engine.
Looks like another winter project, I have another 7.6hp jug that I can switch it out with, as long as the spare is good.
Stinks though because I'm ichin' to see what this unknown tractor has in it for a worm gear.

DSCN3398.jpg DSCN3467.jpg

DSCN3466.jpg DSCN3468.jpg
 

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Wow... I bet you can just hone it out :D
 

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Gravely bug bit.
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They may not have forgotten them Jake. There have been people that put them in and reported losing one due to the clip breaking.
 

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The first time I saw that was in 1973. I had stopped by the Ford dealer to pick up my father's car and saw a like new engine block on the floor. One cylinder had a groove cut in it just like that. It was a warranty job.
 

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Discussion Starter #6
They may not have forgotten them Jake. There have been people that put them in and reported losing one due to the clip breaking.
That makes sense. Thanks for adding that Don. In the top right picture of the mark it almost looks like you can see the outline of the clip at the top of the groove. The other side may have went, and with the pin moving from side to side may have worn the other clip out of the groove of the piston them started to rub up against the wall of the cylinder?? I can imagine the clip wouldn't last long though... Guess I'll find out when it comes apart.

Wow... I bet you can just hone it out
Don't know about that...
The groove is a lot deeper than it looks in the picture, hard to tell with the way it dug in and all, but I'd say it's about .016 to .023 deep, maybe more. It's a fairly good gouge though. Might not be too much integrity in the cylinder once all is said and done with boring it out.

Stuff happens I guess, hate seeing good parts get worn out like this.
 

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There had to be all manner of warning sounds emanating from the engine while the wrist pin was making those grooves. Listening to an engine can tell you a lot. Then again maybe the engine didn't say anything. This happens so infrequently that there isn't any data to go on.

When I put new rings in my CCKA I checked the main bearings too. When I assembled it, I installed the rear main bearing plate wrong. The result was no oil feeding the crankshaft. How did I know something was wrong? I listened to the engine and after about 1 minute of it idling I shut it down. It just didn't sound right. What I was hearing was the extra slop in the rod bearings due to no oil pressure. I could always tell when the engine achieved full oil pressure after an oil change. Anyway, I pulled the engine off the tractor and decided to pull that plate off and quickly discovered my error. A check of the main bearing and rod bearings after that quick run showed no damage. I reinstalled the plate properly and fired it up and then it sounded right.

The moral of the story is to listen to your engine. It actually has something to say.
 

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Don't know about that...
The groove is a lot deeper than it looks in the picture, hard to tell with the way it dug in and all, but I'd say it's about .016 to .023 deep, maybe more. It's a fairly good gouge though. Might not be too much integrity in the cylinder once all is said and done with boring it out.
Don't worry, I was being sarcastic :fing32: It doesn't look good at all. Good thing you have a bajillion spare tractors around now!
 

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That type of failure won't make any noise at all, or should I say certainly none you'll be able to hear on a Gravely engine. I once had a '49 that I bought used (actually paid for it). I knew it was tired, but got it running anyway. It smoked and was down on power, but didn't sound too bad. When I took it apart, the big-end bushing was completely gone, and the older "+" section rod was slightly bent. I also had a failure like this on a mid-seventies Briggs, didn't make any noise at all, just started burning oil like crazy.
 

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Discussion Starter #10
Don't worry, I was being sarcastic :fing32: It doesn't look good at all. Good thing you have a bajillion spare tractors around now!
That is true! Got a few replacements!
Yup, that one went right over my head. Don't always seem to catch those sometimes.....
 

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You could probably have that jug bored out and sleeved to fit the 0.020" over piston that is in it, and get back going with new rings and retainers, not sure what it would cost though.

Joe
 

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That type of failure won't make any noise at all, or should I say certainly none you'll be able to hear on a Gravely engine.
Likely true. It is like trying to listen to lifter noise on a car with no exhaust system on it. The exhaust noise drowns out everything...even rod knocks.
 
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