360 LA getting oil in #3 cylinder.

tinman2 said
My brother in law recently bought this 74 Duster 360 auto from my neighbor who only had it 3 or 4 months. Now I am hoping I didn't lead him to make a huge mistake.
It has plenty of vibration that seems to come and go at different speeds or throttle pressure. Pretty new plugs #1, 4, 3, 6, 7 are black soot covered. Plugs #8 and 5 are light beige. Plug #3 is black crusty. There is some oil smoke coming out driver's side exhaust. Trying to figure out where oil could be coming from. I turned the engine over 2 or 3 rounds trying to see if all the rockers were moving but I did not measure movement. Bought an inspection camera today to look in the cylinders. And #3 cylinder has at least ⅜ inch of oil on top of a clean aluminum piston. I don't think that was left in there after driving it. All other piston tops are sooty black. Does LA 360 oil rockers through passages in block and head? If so, could oil be leaking into cylinder at head gasket from me turning engine over by hand?

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Think about where oil could get in the cylinder.
1: valve guides
2: a stuck open PCV valve
3: rings.
The easiest and least expensive is a PCV valve. Removed it should rattle when shaken. Connected and with the engine running, put your thumb over the air hole. It should click as it seats and unseats.
Rings will wash around the outside diameter of the piston crown.
Guides you can rock back and forth in the direction of intake to exhaust manifolds.
A cylinder leakdown test would be another syarting point after the PCV valve check.
I had a 1969 Chev 1/2 truck with a 292 six, that fouled #5 plug. One guide was worn on that cylinder. Eventually got a reman head, rings and bearings.

tinman2 said
My brother in law recently bought this 74 Duster 360 auto from my neighbor who only had it 3 or 4 months. Now I am hoping I didn't lead him to make a huge mistake.
It has plenty of vibration that seems to come and go at different speeds or throttle pressure. Pretty new plugs #1, 4, 3, 6, 7 are black soot covered. Plugs #8 and 5 are light beige. Plug #3 is black crusty. There is some oil smoke coming out driver's side exhaust. Trying to figure out where oil could be coming from. I turned the engine over 2 or 3 rounds trying to see if all the rockers were moving but I did not measure movement. Bought an inspection camera today to look in the cylinders. And #3 cylinder has at least ⅜ inch of oil on top of a clean aluminum piston. I don't think that was left in there after driving it. All other piston tops are sooty black. Does LA 360 oil rockers through passages in block and head? If so, could oil be leaking into cylinder at head gasket from me turning engine over by hand?

View attachment 1716045382