 Hello all, I finally got time to pull the pistons on the 188 I'm rebuilding and was glad to find the "smoking gun" that was the cause of all the excess blowby. The top compression ring in the #2 cylinder was broken. I've already got a nice kit with new pistons, rings and wrist pins. I was looking through the parts book and I see that the wrist pins ride in a replacable bushing. This bushing has an oil hole that aligns with a hole on the top of the con rod. My first question is: how does oil get to the top of the con rod in the first place? I ask this because two of the rods have bushings that don't have their oil hole lined up with the top of the rod and subsequently I don't see how the wrist pin gets any lubrication. My second question is on the bottom of the con rod there is a small hole that exits out a tiny hole in the side of the con rod itself. What is the purpose of this hole? Pressure relief, or does this "squirt" oil on the cylinder wall? My third question deals with the 3rd (oil) ring on the piston itself. I see that there are several holes cut through the piston around the area where this ring sits. Is this to allow oil to scrape off the cylinder wall and exit under the top of the piston? Is this what supplies oil to the hole in the top of the con rod that in turn lubes the wrist pin bushing? My fourth question is about the con rod cap nuts and bolts. Is there any reason to replace these or can they be re-used? I'm showing my ignorance here but how do the cylinder walls get lubrication in the first place? I always was under the impression that engine oil ran through the crank and up through the con rod and was allowed to spray/dribble out the middle of the oil rings. I don't see how this could be the case though as the con rods appear to be solid in the middle (no oil passage). I'm planning on replacing the wrist pin bushings anyhow as the old ones show some signs of overheating, especially the two that don't have the oil hole lined up with the con rod. The old wrist pins looked fine though and the bushings themselves appear to be within tolerance. Thanks!
John
1968 Case 450
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