Originally Posted by scubar
Upon removing the valley pan on a 1987 460 motorhome engine with 31K miles,
I noted that the underside center of the valley pan has a significant buildup of crusted oil where it goes under the carb. The rest of the valley pan is clean, see picture. I'd appreciate any thoughts on what is causing this buildup so I can deal with it before I put it all back together (rebuilt heads and carb).
The sludge is due to the intake manifold's exhaust crossover. Run a quality, non-paraffin based motor oil and change it regularly. Also, make sure that the intake manifold's exhaust crossover is not blocked with carbon buildup.