Quote:
Originally Posted by G_Don
Hey Guys,
I have a B motor which was supposedly rebuilt (no receipts, but looks clean with oil pan removed and head off), which was experiencing blow by out of the oil filler tube and would get hot after only running it for a minute or less.
I removed the head, pulled the pan and removed the first and second pistons. Attached is a picture of the piston #1. Piston #1 has wear in both the front and back of the piston like that where the rings are melted to the piston. Piston 1's rings were not equidistant apart and the ring seams were only about 15 degrees off of each other. Was this a result of the overheating issue or the cause of the overheating/blowby issue? I heard rings being spaced like this allows for gas to escape, but is it the same for oil? Piston 1 was also quite difficult to remove from the cylinder, and I ended up using a wooden dowel to lightly tap it up and out of block.
Piston #2 which isn't shown but is similar has wear on only the front of the piston. The rings are set at more of a distance, probably 120 degrees off. Piston 2 was much easier to remove than piston 1, although I still needed to lightly tap it with a hammer.
The block was supposedly bored 0.080" over from the etching on the pistons. I measured all 4 cylinders using a telescope gage and 3-4" mic. They were consistently 3.954". But 0.080" overbore on 3.875" cylinders should theoretically be 3.955".
The pistons measured 3.931" and have 3 rings on each piston including the oil ring. There is a slight buildup on the cylinders of what I'm assuming is melted aluminum from the pistons.
Im curious as to whether or not the cylinder bore was not honed enough (there was cross-hatching) seeing as it measure 0.001" small, which caused it to overheat, or if it was the rings being set improperly in the first cylinder that cause the engine to overheat.
Thanks in advance!
Gordo
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Rest assured that your problems were NOT caused by the location of the ring gaps. As already mentioned, rings rotate in their grooves when the engine is running so the gap locations are always changing and will not affect how the engine runs in any way, shape, or form! This ring gap myth is just a lot of malarkey, blarney, baloney and hot air!