5.3oilchugger

Hello
I recently purchased a used 6.0L with 66k miles for a swap on for my oil burning lifter tapping 5.3 engine.
I pulled the heads to have them milled and install heavier valve springs. I turned the passenger side cylinders up level on my engine stand and poured a half inch or so of Marvel Mystery oil in the four cylinder on that side hoping it would seep through the rings and loosen any gunk on the rings if there is any.
The next morning the oil in cylinder# 6 was drained completely and the other three cylinders had drained only a little. I poured more MMO in cylinder 6 and it drained in less than 4 hours. The other cylinders took 3 days for the MMO to drain through the rings.
The amount of carbon and color on cylinder#6 piston is the same as the rest of the pistons. I looked at the combustion chamber on the head and noticed the exhaust valve on cylinder 6 was a much darker color than the rest of the exhaust valves light gray color. The spark plug ground strap is clean with shiny metal. The other spark plugs have a light gray color similar to the other exhaust valve.
I looked closer at cylinder#6 and noticed it looks like some streaks on the cylinder but nothing that I can feel. I'm not sure if this is a fueling issue or an ignition issue.
Any help on this would be greatly appreciated.


The third from left is combustion chamber#6





Notice how clean the spark plug ground strap is

ZO6Ted

Bump! Hell I'm dying to know about this one but been too long since I was paying attention to this stuff. What do you think guys? Bad injector causing lean out? Plug is shiny. Exhaust valve dark from oil in the cylinder? Inquiring minds want to know. Been a shitty day for the country need some diversion...

5.3oilchugger

I pulled the pistons and the cylinders all looked a bit glazed with light crosshatch visible. #6 cylinder is the only one that has some vertical streak lines in the bore and its the only cylinder that has a lip at the top of the cylinder where the top ring stops. I can feel where the piston skirt met BDC. The piston shows a little more skirt coating worn off on cylinder 6.
I think this engine was neglected as it stinks inside. The oil rings are pretty much gunked up and stuck. I'm starting to think that the spark plug was removed and cleaned probably because it has fouled. The only other reason for a clean plug in my opinion is that maybe the the cylinder was getting fuel but no spark. Maybe the fuel washed the plug and the cylinder. Not sure if fuel without fire would be enough to wash the oil off the cylinder and cause more wear in this cylinder.
The block is stripped and heading to the machine shop for boring tomorrow. Now I need to decide what pistons to use for keeping the same stock compression with a 4.020" or 4.030" bore. Thankfully the crank and bearings look new.