POH Oil Quantities

[Wayne Pearce]

Why does my '73 337G POH state engine oil quanitites as 10 quarts, my dipsick shows a maximum of 8 quarts and the 337H POH state 8 quarts, needless to say I run a maximum of 7 to 8 quarts depending on length of trips (typically 4 to 12 hours)

This 2 quart discrepency seems very strange even considering things like external filters etc...etc

Inquisitive........Regards ..........Wayne

[Mark Hislop]

Wayne:

Great minds think alike. I was just getting ready to ask the same question. My POH for 73 P337 also shows 10 quarts capacity. My dipsticks are marked only for 8 qts max. I've never been able to put in more than 8.5 qts during oil changes with new filters. I have one new factory reman and one Rolls Royce, and they both are the same. I don't know why the difference, either.

Mark

[kevin]

As long as we are on the subject, I have had five Skymaster engines in my life. All had 8 quart capacity as you describe (plus 1 quart in the filter, total 9, i.e. fill it to eight, run then engine, now you can put in another if you desire), and all will toss anything more than 5 - 5.5 quarts into the slipstream in short order. If I refill by adding a quart at 5 or just under, I use very little oil. If I refill at 6 to 7 quart level, I use a half a quart per flight for the first two flights, and then very little. Anybody else have this experience, or am I living in some alternate, oilless, universe?

Kevin

[Bob Cook]

I run between 6 and 6.5 qts. I use NO oil for first 18-20 hrs then 1/2 qt. Burn the next qt in 5-10 hrs. If I put in 7 qts I end up with 6.5 in short order regardless of time on engines. I keep it within 6 to 6.5. Mine has the oil seperators which is std on all P's ( i believe). Both engines are low time factory remans.

bob

[Wayne Pearce]

So it seems you guys run your engines on about 6 quarts, I also have separators and I like to run mine on about 7 quarts, but I generally do longish trips around the Northern Territory, the oil temps remain quite cool but I also tend to leave an oil vapour trail behind me all over the tail.

Wonder why continental specify 8 quarts if engine runs ok on 6 quarts and breathes less oil ........ does this mean those without separators breathe even more oil ???

Regards

[Bob Cook]

Wayne

Seems that is the case. The tailfeathers remain quite clean. I need to clean off the bottom about every 30 hrs. I just ran 14 hrs without adding any oil to either engine. The seperators do help.

Bob

[GMAs]

Welll that is kinda like soup... some say less salt.. some say more..

While true you can run on 6 qts in the pan... for the no nothing dummy who is going to sue the pants off of cont and cessna... they want it full...8 qts... for any flight... but,....

we all know how much our engines burn in oil and how much it pitches out... because of the bad rings and worn engine parts... so we only fly 4 hours at most... and that is good enough to maintain the 6 qt cap. but, what if it starts to burn more... ow much does a engine cost... vs the oil left on the backside... if you run out of the 6 qts... smile...

If you know and your engines are keeping good logs on the rate of oil burn you can get away with less... I agree... but, if you pin me to the wall... I have to go with what the poh and manufacture says... and that is 8 qts.. for any flight over so long ... I think it says...

Now the reason that bob is burning more after a time ... is because the oil is breaking down... and sheering... into a thiner oil... one reason to change it at 25 hr intervals... or max 50 on trips...

the original 10 came from the 8 in the crankcase 1 in the filter and one in the engine... for long flights... but, we are not taking flights over 8 hrs lately so we haven't used the max oil level thing for a while... as over filling is just as bad as too little... if the engine gets bounced around and the oil comes up and hits the rods or crank... not good.... so we stick with the 8... and that is 8 going into the engine... not on the stick... as some of the sticks were wrong... you put 8 in and it reads 6.. kinda thing... cont has a notice out about that and you can check it out on their website...

But,,,, 8 in the case is what you go by... when you replace your oil.... not what is on the stick... and if you change filters... well ya it says one qt more... but, if your not buring a whole lot and you feel comfortable with the lower limit... you can go that way... just don't go below 5.... for short flights... and any trips... start off with 7 or 8 and go down from their...

but, remember its 8 going in the case... not what the stick says... its real important... to calibrate your stick to read right... else you could be too full or too low... check the next time you do a oil change... put 4 in... check... put 5 in... check after a min... put 6 etc... and make a note in the log book that you calibrated your dipstick... too... if its off check with cont engine rep... or your mechanic... but, till it gets fixed if it is.... keep a conversion chart you made up in the log book for referance... for both engines... smile... GMAs

[Bob Cook]

Keep a log! tells a lot.

I replace the oil between 25-30 hrs. Filters at 50! The oils starts to get dirty at about 18hrs.

There is also an SB from TCM on the dipstick for the C and CB engines. They want a specific part number and if you do not have it they will send you a new dipstick.

fyi

bob