gunk under intake manifold

TrailBeast said

I didn't mention that because I didn't want to open yet another oil debate, but I have seen that as well on a lot of Pennzoil motors.
My Dad swore by it, but after seeing what I have three's just no way.
I even bought a Honda dresser motorcycle because I felt sorry for it when I saw a Pennzoil bottle sitting next to it when the guy said he just changed the oil.
I swapped it out for Castrol GTX before I even left with it.:D

Click to expand...

Quaker State as well back in those days.....

For the OP: One motor I took apart that looked like that inside had an internal carb leak for years. It would leak gas into the intake when stopped, and gas would seep down past valves and rings into the crankcase and oil. That worked with the old oil to produce bad sludge like that. It also wore the cylinders pretty badly so who knows what you will have when you fire it off....