What is my DC head telling me?

Fry

Member
After a week or so of highs below 0, it finally warmed up enough a few weeks ago for me to fire up the DC. It struggled to start and
maintain RPMs. After idling for awhile, I noticed oil leaking out of the exhaust manifold by the gasket. A little bit later oil had worked
its way up the exhaust elbow to the muffler. Finally, there was a small "poof" of an explosion and it shut down. I could see metal shards
through the weep hole in the elbow. Fearing a valve issue or a head gasket problem, I pulled the head. After further review I'm fairly
certain the oil was from the air cleaner and was somehow getting sucked through the system. The metal shards were the intake/exhaust
manifold rings.

I've never pulled a head before so I don't know what, if any, information can be gleaned from the different colors of the valves and such.
Is there anything I should be looking for here or any tell-tale signs?
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The "oil" leaking out of the exhaust manifold gasket was simply condensed "combustion byproducts".

Should have warmed the engine up and worked the snot out of it before recklessly tearing the head off, IMHO.
 
(quoted from post at 23:42:45 02/03/17) The "oil" leaking out of the exhaust manifold gasket was simply condensed "combustion byproducts".

Should have warmed the engine up and worked the snot out of it before recklessly tearing the head off, IMHO.


If you did not install new plugs recently the mixture is way lean, the snow white insulators show excessive temperatures, normal porcelain color should be a medium brown, not dark oily but brown, the richer the mixture the darker the plug color will be. Dark wet plugs indicate fouling usually caused by oil consumption. I would lean toward a carb problem possibly only a to lean setting on the high speed mix needle or a restricted fuel flow from the tank.
 
Those air cleaners were prone to getting water in them, and when that happens, the oil floats up and gets sucked into the engine. Mel gave you a good description of the colors on the valves, and I to, think you wasted your time pulling the head off.
Loren
 
well shux,, experience is the bezt teacher ,.. learning at hard knox scholl can be tuf ,,. now you and I know the why of the colors and burn patterns ,,. and you get to lern how to properly retorquwe the head ,.john saeli, napa,or yourfriendly case ih dealer will have a headset ,. the guys here will coach you on the retorqe , make sure you gt the block and headclean spotless,.. while you got it off just as well grind the valves and put new springs on it ,...
 

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