What would you consider a normal oil consumption for the O-300/C-145 HP engine?
Bruno
Fort Smith, NT
Oil consumption
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
OIL AS WATER
TO ANSWER HONESTLY "THERE AIN'T NONE". 
NORMAL IN ANYTHING BUT AN OLD "O" CONTINENTAL WOULD BE ABOUT A QUART IN THREE OR FOUR HOURS. FOR MANY C-145 OR O-300 ENGINES IT CAN BE FROM THAT TO TWO OR THREE PER HOUR! A QUART PER HOUR IS NOT UN EXPECTED, THOUGH IT IS DISGUSTING.
NORMAL IN ANYTHING BUT AN OLD "O" CONTINENTAL WOULD BE ABOUT A QUART IN THREE OR FOUR HOURS. FOR MANY C-145 OR O-300 ENGINES IT CAN BE FROM THAT TO TWO OR THREE PER HOUR! A QUART PER HOUR IS NOT UN EXPECTED, THOUGH IT IS DISGUSTING.
oil consumption
Interesting topic. I would be interested in knowing if high or low consumption can necessarily indicate health of the engine, or is each engine different just like people?
I have an O-360 that blows everything above the 6 Qt. mark overboard, but only burns about 1/2 quart every 4 hours after that. I don't know if that's good or bad. I'm thinking that's pretty low consumption, on the other hand I expect the engine to use something.
Thoughts anyone?
I have an O-360 that blows everything above the 6 Qt. mark overboard, but only burns about 1/2 quart every 4 hours after that. I don't know if that's good or bad. I'm thinking that's pretty low consumption, on the other hand I expect the engine to use something.
Thoughts anyone?
In between the 25 hour changes, mine sometimes needs 2, and sometimes 3 quarts. I put 7 quarts in at the change, and the next one is needed within 2 - 3 hours after that for some reason. And then, it is either 1 or 2 more during the 25 hours. Any more than the 7 at change is blown out of mine also. The lower the reading gets towards six quarts the slower it gets on needing the quart.
Joe
51 C170A
Grand Prairie, TX
51 C170A
Grand Prairie, TX
Oil Consumption
I have a C145, about 1400 SMOH and 600 STOH, it burns about a quart in 6 to 8 hrs depending on how hard it is run. 2300 rpm about 1 quart in 8 hrs above 2400 about a quart in 6 hrs. Compressions at last annual were all 76/80 or higher. It has an oil leak through one of the case bolts, we believe one of the case through bolt o-rings is leaking.
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Bill Venohr
- Posts: 90
- Joined: Tue Apr 23, 2002 1:42 pm
When I first bought my plane 2 1/2 years ago, it burned a quart every 3-4 hours. Flying it over 100 per year, it is now about a quart every 7 hours. I'm getting a cylinder overhauled right now and will be interested to see my oil consumption. By the way, any recommendations on how to break in a new cylinder? My mechanic is recommending continuing with the 50W detergent rather than going to a mineral oil--said if it were more than one cylinder he might recommend the mineral.
Bill Venohr
N4044V
Aurora, CO
N4044V
Aurora, CO
I purchased my 170B in June. Have 51 hours on it since then. Just completed a family vacation to Texas and back. In the 30 hours since last oil and filter change, I have added 9 quarts 
Never going above 6 quarts at any time and engine always turning 2450 in cruise. 900 SMOH...but that was done in 1974 
450 STOH. I have several pushrod tubes leaking from the rubber seals near the base of the cylinders, and these will be replaced soon. I suspect some oil blowing out the breather pipe, which an M20 air/oil separater will hopefully reduce. One weak cylinder noted on the prebuy, but A&P said it was from the exhaust valve and to just run it until next annual and see if compression comes up. The only thing that really bothers me at this point is the oil gets black quickly after the oil change 
I'm used to oil staying nice and clear in my MGB for thousands of miles 
Is black oil bad...or just normal in an O-300.....or both 
Never going above 6 quarts at any time and engine always turning 2450 in cruise. 900 SMOH...but that was done in 1974 450 STOH. I have several pushrod tubes leaking from the rubber seals near the base of the cylinders, and these will be replaced soon. I suspect some oil blowing out the breather pipe, which an M20 air/oil separater will hopefully reduce. One weak cylinder noted on the prebuy, but A&P said it was from the exhaust valve and to just run it until next annual and see if compression comes up. The only thing that really bothers me at this point is the oil gets black quickly after the oil change I'm used to oil staying nice and clear in my MGB for thousands of miles Is black oil bad...or just normal in an O-300.....or both John, 2734C in Summit Point, WV
John, that would be what I would worry about too, hate to hear that your oil gets black quickly. Mine stays clear for most of the 25 hours, but I have wanted to switch to a 20 hour interval to improve that. Maybe it is the weak cylinder allowing the oil to get contaminated.wa4jr wrote:I purchased my 170B in June. Have 51 hours on it since then. Just completed a family vacation to Texas and back. In the 30 hours since last oil and filter change, I have added 9 quarts
Joe
51 C170A
Grand Prairie, TX
51 C170A
Grand Prairie, TX
"Oil consumption at a rate of 1.25 lbs/40 minute run maximum is acceptable."- from TCM Manual X30013. This equates to about 1 quart per hour.
My own O-300 uses 2 qts every 25 hours. I fill it to 7 quarts after an oil change. It remains fairly clear for 15-20 hours by which time it's taken on a dark golden hue. It darkens slightly faster after that. I have the engine on a 25-hour change schedule, with spin-on filter, using AeroShell 100W (SAE-50, AD).
Oil that darkens quickly is not necessarily a bad thing. Most darkening is due to carbon particles suspended in the oil. The primary source of such carbon is the lower face of the piston dome, which is cooled only by oil-splash. That oil is carbonized by high temps and is washed into the sump. A good filter will remove much of it, but the amount you generate is going to be highly dependent upon how lean you run (how much heat you're generating) and which piston part numbers are installed. Some piston designs run hotter than others according to presence/absence of lower-surface webbing, etc., and operator technique. (I personally run so as to err on the rich side of max EGT, because I haven't an EGT gauge. The technique I use is that suggested by TCM in their Operator's Manual for this engine, which is to slowly lean until maxumum RPM, then richen until first indication of RPM decrease.) If my MGB's oil remained clear after a thousand miles, I'd change oil brands/type. Automotive oil (additive-type) should indicate suspended particles much sooner than that, because it is a detergent oil (unlike aero oil which is a dispersant oil.)
The widely varying results we are all reading here may be reflective of the fact that Ole GAR uses fish oil, Eric uses snake oil, and Joe uses olive oil, Extra Virgin.
My own O-300 uses 2 qts every 25 hours. I fill it to 7 quarts after an oil change. It remains fairly clear for 15-20 hours by which time it's taken on a dark golden hue. It darkens slightly faster after that. I have the engine on a 25-hour change schedule, with spin-on filter, using AeroShell 100W (SAE-50, AD).
Oil that darkens quickly is not necessarily a bad thing. Most darkening is due to carbon particles suspended in the oil. The primary source of such carbon is the lower face of the piston dome, which is cooled only by oil-splash. That oil is carbonized by high temps and is washed into the sump. A good filter will remove much of it, but the amount you generate is going to be highly dependent upon how lean you run (how much heat you're generating) and which piston part numbers are installed. Some piston designs run hotter than others according to presence/absence of lower-surface webbing, etc., and operator technique. (I personally run so as to err on the rich side of max EGT, because I haven't an EGT gauge. The technique I use is that suggested by TCM in their Operator's Manual for this engine, which is to slowly lean until maxumum RPM, then richen until first indication of RPM decrease.) If my MGB's oil remained clear after a thousand miles, I'd change oil brands/type. Automotive oil (additive-type) should indicate suspended particles much sooner than that, because it is a detergent oil (unlike aero oil which is a dispersant oil.)
The widely varying results we are all reading here may be reflective of the fact that Ole GAR uses fish oil, Eric uses snake oil, and Joe uses olive oil, Extra Virgin.
Wow One quart every hour acceptable by TCM One might tend to think that TCM has stock in AeroShell 
Thanks for making me feel good with my oil consumtion rate of 1 quart every 3.3 hours average. I suppose I need to start work on the auxiliary oil tank mod for those long XC flights if the pushrod tube work doesn't stem the flow of oil away from my engine
One quart every hour acceptable by TCM One might tend to think that TCM has stock in AeroShell Thanks for making me feel good with my oil consumtion rate of 1 quart every 3.3 hours average. I suppose I need to start work on the auxiliary oil tank mod for those long XC flights if the pushrod tube work doesn't stem the flow of oil away from my engine John, 2734C in Summit Point, WV
SNAKES AND VIRGINS
IFN WE CUD COUNT ON JOE, WEED AX HIM TU BRANG SUMA THEM EXTRA VIRGINS TU OUR NEXT DOO. TRUBLE IS HE DOANT NEVER GIT TO ANY SO CUD WE GIT HIM TO FED EX EM OVER HEAR AN ILL TOOK GUD CARE OF EM TILL THEN? ALSO GAY HORN MY FISHY PEENUT OIL DOANT SMOKE AND DOANT TURN BLACK. THE LEFT OVER MEAL THAT FALLS OFF THU FISH PLUGS UP THE CRAKS IN MA OIL PAN. SNAKE OIL AINT GUD FER NUTTIN BUT JES SLIKIN UP FIBBERS! I AINT SURE BUT WHAT YOU GOTS SOME FRUM ERIK. 