Dipstick markings

Half Fast

Half Fast

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Half Fast
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The oil dipstick for my O-360 has markings at the 4, 6, and 8 quart points (I'm guessing that's universal). It'd be helpful to have marks at 5 and 7, so I'm curious about a good material/method to add marks. I thought about just making small marks with a Sharpie, but I suspect hot oil would remove them in no time.

Any suggestions?
 
talk about a first world problem ;)

I have to make an educated guess if I have 4.5 or 5 quarts of oil in my airplane engine. waaah ;)

Buy a Nanchang. I've got about a 2 gallon margin of error. ;)
 
Salty said:
talk about a first world problem ;)

I have to make an educated guess if I have 4.5 or 5 quarts of oil in my airplane engine. waaah ;)

Buy a Nanchang. I've got about a 2 gallon margin of error. ;)
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Yeah, I never sweated it before, but at the moment I’m trying to track how my consumption is improving during break-in, so it’d be nice to have a little more accuracy on whether it used 1 or 1.5 quarts on a flight.
 
Bell206 said:
A small file. To add, on sticks that are applicable to LH or RH applications we would grind off the non-applicable scale.
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I was worried you’d tell me it’s a major mod and I’ll need to get a DER involved....
 
Half Fast said:
The oil dipstick for my O-360 has markings at the 4, 6, and 8 quart points (I'm guessing that's universal). It'd be helpful to have marks at 5 and 7, so I'm curious about a good material/method to add marks. I thought about just making small marks with a Sharpie, but I suspect hot oil would remove them in no time.

Any suggestions?
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1755539936001.jpeg
 
Half Fast said:
The oil dipstick for my O-360 has markings at the 4, 6, and 8 quart points (I'm guessing that's universal). It'd be helpful to have marks at 5 and 7, so I'm curious about a good material/method to add marks. I thought about just making small marks with a Sharpie, but I suspect hot oil would remove them in no time.

Any suggestions?
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How do you account for a full oil filter when the engine is hot and oil level variations with different nose strut extensions?

As with many things on airplanes, the marks on the dip stick is an indication not a measurement.
 
Clip4 said:
How do you account for a full oil filter when the engine is hot and oil level variations with different nose strut extensions?

As with many things on airplanes, the marks on the dip stick is an indication not a measurement.
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I take my readings when the engine has cooled, in my hangar, a day or so after a flight. This gives time for the oil to cool and to drain into the sump. I'm breaking in an engine, and one prime indicator of the rings having seated properly is for the oil consumption to stabilize at approximately a normal rate.
 
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There’s nothing you can do about consumption except maybe to limit the oil to 6 qts so the first two don’t blow out of the breather. Pick what line you want to use, add as you wish to maintain that level, and quantify consumption by the empty containers on the bench.

Rings should be broken in by 3-4 hours.
 
I've wondered if the current markings might be made more clear as I struggle to read the new dipstick. Would it be harmful to use a permanent marker on the dipstick? Perhaps a fat black line around the 6 qt mark would make checking level somewhat more obvious.
 
Half Fast said:
The current markings are linear, so I’ll just measure distances.
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Are you sure there aren't local minima/maxima? I seem to remember a discussion here about that and my observation supports the non-linearity theory.
 
Stewartb said:
There’s nothing you can do about consumption except maybe to limit the oil to 6 qts so the first two don’t blow out of the breather. Pick what line you want to use, add as you wish to maintain that level, and quantify consumption by the empty containers on the bench.
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This sent me down a rabbit hole of reading because I wanted to understand why it seemed like engines behave like this and what the best practices really were. I still don't have that answer.

But I did find FAR 33.39 which specifies: "The lubrication system of the engine must be designed and constructed so that it will function properly in all flight attitudes and atmospheric conditions in which the airplane is expected to operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant supply is in the engine."

So, by rule, my IO-360 must operate properly with 4qts. Anything less than that is not required by the FAR.

asicer said:
Are you sure there aren't local minima/maxima? I seem to remember a discussion here about that and my observation supports the non-linearity theory.
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Yeah, that's what I was wondering also. If I'm betting, I'm betting that his statement about it being linear is right. But there is no reason it has to be. The shape of the oil reservoir could be weird and not be linear in between the existing markings.
 
asicer said:
Are you sure there aren't local minima/maxima? I seem to remember a discussion here about that and my observation supports the non-linearity theory.
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Sure enough. When it shows 5.5 qts and I add a quart, it comes up to 6.5. Same from 5 to 6 and 6 to 7. Over the range I care about, it’s close enough to linear for my purposes.
 
Half Fast said:
Sure enough. When it shows 5.5 qts and I add a quart, it comes up to 6.5. Same from 5 to 6 and 6 to 7. Over the range I care about, it’s close enough to linear for my purposes.
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I'll have to re-check the calibration of my eyeballs :)
 
Half Fast said:
Yeah, I never sweated it before, but at the moment I’m trying to track how my consumption is improving during break-in, so it’d be nice to have a little more accuracy on whether it used 1 or 1.5 quarts on a flight.
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Be more patient and track how many quarts you add over 10 hours or so. I think you are looking for accuracy that’s tighter than the precision of your measurements. 10 quarts in 10 hours is easy to measure with your existing stick and is more accurate than 1 quart in 1 hour.
 
Salty said:
Be more patient and track how many quarts you add over 10 hours or so. I think you are looking for accuracy that’s tighter than the precision of your measurements. 10 quarts in 10 hours is easy to measure with your existing stick and is more accurate than 1 quart in 1 hour.
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Agree with this, but flip the numerator and denominator. All you really need is the 6 quart line. Whenever you reach it, add a quart and subtract the previous tach to get hours per quart. By 25 you should be adding a quart every 8 to 10 hours, and you'll know it's time to switch to regular oil.
 
Salty said:
Be more patient and track how many quarts you add over 10 hours or so. I think you are looking for accuracy that’s tighter than the precision of your measurements. 10 quarts in 10 hours is easy to measure with your existing stick and is more accurate than 1 quart in 1 hour.
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keeping track of how many qts. thats cute. how about how many gallons......
 
luvflyin said:
How long does it take you to go through one? Oxidation is a thing with oil. You may want to research it.
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Looking like less than a year. I originally thought it would be 2 years and figured I'd sell to the other 4 guys with radials on the airport, but I haven't done that yet since I seem to be consuming it faster than I expected. I finally fixed my big leak, but oddly usage doesn't seem to have gone down much.
 
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Following some stuff I read on the internet I “calibrated” mine during an oil change. I let the oil drain for 2 days (was intending overnight but got delayed). I then added 1 qt and waited an hour and noted where the oil was relative to the marking on the dipstick. I repeated that for each of the 7 remaining qts. I did not start the engine so the qty in the oil filter shouldn’t factor in to the sump oil level. For my airplane 8 qts was marked as 7 qts on the dipstick. Sort of explained why it would use oil rapidly until the 6 qt marking and stay there. The 6 qt marking was really 7 qts.
 
Half Fast said:
Yeah, I never sweated it before, but at the moment I’m trying to track how my consumption is improving during break-in, so it’d be nice to have a little more accuracy on whether it used 1 or 1.5 quarts on a flight.
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If you need half quart data better add some half quart lines also. But why stop there?
 
I just went through this with some new cylinders / rings this summer. First 3 hours used 3 quarts of oil. After that, it's been 6 hours to a quart for the last 30 hours.

Fun Fact - the oil requirement rules for engines were set in the 1940's or there abouts, requiring the "full" level provide twice as much as the minimum required. Probably based on the oil consumption with radials. So my dip stick shows "Full" at 12 quarts, which means it can get a low as 6 and still run fine.

M2C - Given all the lead and heat removal whatnot oil has to deal with, I'll keep it as close to "Full" as possible. For whatever reason though, some engines will toss out oil above a certain amount - just a quirk of engines. My engine seems to like 9 quarts.
 
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