Oil Burn in a 0-360 ?

[pvansrv3]

PC Hunt is close, as mentioned.

The FAA requires engine and airframe makers to design the engine oil capacity to be big enough so that if the engine is burning oil at the maximum allowable rate approved by the engine maker, that the airplane will run out of fuel before it runs out of oil.

So if the airplane has a 5 hour fuel endurance, and the engine is considered healthy with 1 hour per quart burn, then you need 5 quarts more capacity in the sump than the minimum it needs to run.

So most sumps are much bigger than necessary, and with all the splashing and frothing going on in there when the sump is full it ends up going out the breather.

If you have a good seperator it will minimize this to a great extent.

[zilik]

Mahlon had the best reasoning but still don't buy it. If the engine has a lot of blow-by then there is something else wrong. I really don't think volume of the crankcase will effect pressure change with a constant size exit opening.

The comment about the crank and rods splashing around in the oil would only happen if you put more than 8 quarts in the sump. The sump, sitting on a work bench holds just at 8 quarts and the crank is spinning above it with a crankcase separating the crank housing from the oil sump.

[zilik]

Originally Posted by plehrke

If I put 8 qts in my 0-360 I get a rapid reduction to 6 quarts in under 10 hours. It is all most likely coming out of the breather as the belly gets plenty messy. When it gets down to 6 quarts it stays there until my next oil change and the belly is much cleaner. I actually now only put in 7 quarts at oil change and then add the 8th quart at around 18 hours to keep it above the 6 quart line on the stick. I call that "no oil consumption" as I only use 8 quarts total for the oil change cycle.

2 quarts in the first ten then stays at 6 for the remainder of the oil change. So during the last 15 to 40 hours (depending on 25 or 50 hour interval) the engine consumes none. 15 hours, zero oil consumption. I believe that.

Second scenario: Seven quarts at oil change, 1 quart 18 hours later to keep it above 6 quarts so I must assume it dropped to 5 or 5.5 quarts or you would not have added oil. So thats 1.5 to 2 quarts used in 18 hours yet you say "no oil consumption". Hmm. Must be new math.

My engine uses the first quart more slowly than the second. I dump 8 in at oil change and about 10 hours later I have to put another quart in as the stick is on 7. At 20 hours I'm sitting at 5.75 on the stick but don't usually bother to add oil since the oil change is only 5 hours away. Probably use another .5 to .75 quarts in the last 5 hours. So that gives me a consumption total of 2.5-2.75 quarts in 25 hours. Old math.

So as you can see, when we're hangar flying and talking about oil consumption we're comparing apples to oranges.

[Rivethead]

So many variables. Here's a picture of the top side of the sump area though.

[rgbewley]

Did the engine have o'h cylinders at time of build and are they chrome?