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Removing my air/oil separator & can I use stainless NPT fittings in IO-360 block?

moespeeds

Well Known Member
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2 questions-

First, can I use a stainless NPT "Swivel" fitting in the crank vent? It eliminates the tight bend on the vent hose. I've never seen a brass 90 swivel...

Second, can I dump my crank vent into the fitting welded to my exhaust for the air/oil sep? I don't see any reason why I couldn't just checking.

My oil gets dirty very fast, like 5 hours. Compressions were 74/76/76/76 and borescopes look good. I'm trying to see if ditching the separator cleans up the oil. I don't have high hopes, but simple stuff first.
 

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Moe, you can, minor issue of the inner stem diameter and it allow the engine to breathe.
I made this one YEARS ago for a client with a convoluted hose--
Tom
 

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My oil gets dirty very fast, like 5 hours. Compressions were 74/76/76/76 and borescopes look good. I'm trying to see if ditching the separator cleans up the oil. I don't have high hopes, but simple stuff first.

Oil typically gets dirty from blowby (combustion gasses leaking past the rings into the crankcase). The more you have, the faster the oil turns black. There is no easy way to stop this and changes to the CC venting will do nothing to help it. I will say that the more blowby you have, the more caution must be applied to proper venting, as you have more air that needs to be removed. Don't know much about swivel fittings, but be sure that the new fittings do not have significantly smaller internal diameters.

Dumping the oil into the exhaust seems to be popular, but those check valves get coked pretty quickly and need routine cleaning. If it fully clogs, oil will back up in the separator and could reduce the air flow through it. I just dump the oil collected from the separator back into the engine, where it came from to begin with. This approach helps to reduce oil consumption that is caused from blowby.

Larry
 
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Dumping the oil into the exhaust seems to be popular, but those check valves get coked pretty quickly and need routine cleaning. If it fully clogs, oil will back up in the separator and could reduce the air flow through it.

Larry

…. and it can cause the front seal to blow and force a landing!

Good points Larry but I’ll live with a dirty belly and oil is cheap at the rate mine uses it. Just not worth the risk and I don’t need another maintenance item.
If your going to use a check valve, follow Larry’s advice and check it often.
 
Oil typically gets dirty from blowby (combustion gasses leaking past the rings into the crankcase). The more you have, the faster the oil turns black. There is no easy way to stop this and changes to the CC venting will do nothing to help it. I will say that the more blowby you have, the more caution must be applied to proper venting, as you have more air that needs to be removed. Don't know much about swivel fittings, but be sure that the new fittings do not have significantly smaller internal diameters.

Dumping the oil into the exhaust seems to be popular, but those check valves get coked pretty quickly and need routine cleaning. If it fully clogs, oil will back up in the separator and could reduce the air flow through it. I just dump the oil collected from the separator back into the engine, where it came from to begin with. This approach helps to reduce oil consumption that is caused from blowby.

Larry

I cut a whistle slot in my hose “just in case” the valve closes up between inspections/cleanings.
 
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