Engine Not Coming Up to Temperature

[Guest]

Re: Engine Not Coming Up to Temperature

I suspect that the amount of moisture imposed on the oil is related to cylinder, piston and ring condition.

A sloppy cylinder, ring, piston assembly will blow more moisture into the oil system. Probably many engines fit that description.

If one had a really good cylinder, piston, ring condition it should not impose too much moisture.

Perhaps Marty you have a good engine that just does not produce much blow by and water thereby the vent system seldom gets condensate?

Of course if prior experience shows that to be untrue my conjecture is void.

Dave

[3Dreaming]

Re: Engine Not Coming Up to Temperature

Marty, until you check the gauge you don't know for fact that the engine is really running cooler. When talking with someone about a oil temperature or pressure problem with a engine the first thing they will tell you is check the gauge.

[M Towsley]

Re: Engine Not Coming Up to Temperature

Dave,

She seems to be a good engine with very good compression. Thanks for the thought on that.

Tom, I will check temps. Especially the new gauge before installation. Thanks.

[astjp2]

Re: Engine Not Coming Up to Temperature

So how many of you have read the skyranch engine manual? a lot of this is discussed in it and what temps you need to have for how long. I think I remember it needs to run for 1 hour at a specific temp to get the moisture out. Its not for corrosion purposes as much as the combustion process forms acids that get in the oil when there is moisture present. Tim

[Scott]

Re: Engine Not Coming Up to Temperature

Hi Marty
Water out of the breather is good. It indicates that moisture is indeed evaporating from the oil while your running. Similarly, moisture under the oil cap indicates water is vaporizing during flight. It then condenses on the cap cuz its cool.
What colour is the oil on the dipstick? If it's greyish perhaps you have a moisture problem. If it's black or any shade of amber you're good.

What oil are you running? Some oils do better than others when it comes to absorbing moisture. Synthetics generally do better with water. If you're running straight weight oil and you have high relative humidity where you store the aircraft, I wouldn't leave the oil cap off. Oil absorbs moisture from the air. With the cap on, total available moisture is only what's in the crankcase. With the cap off ambient air is basically a limitless supply of moisture.

I have a dehumidifier in my hangar, It's filled up a 55gal drum twice since June (my water supply for hand washing, alumiprep, alodine etc!) and Thunder Bay seldom experiences high relative humidity. I firmly believe the way to keep water out of oil is to not let it get in in the first place.

[M Towsley]

Re: Engine Not Coming Up to Temperature

Oil on the dipstick appears water-free. Running 20W-50 Exxon Elite. Central Illinois is the humidity capitol of the world, or so it seems. The corn loves it.

[Mark Bowden]

Re: Engine Not Coming Up to Temperature

Hi, Dave's comment on rings is a good one. I have a number of old and more recent Continental manuals and they state minimum oil temp is 90 F. Normal operating range is 120-200 F., maximum is 220. A 1980 year manual for the A65 states 120-180 F as normal. Thus 170 is in the top 20% of the normal range. The probe is at crankcase oil entry point so it is the "coldest" oil in the loop. Water removal happens at the piston and over the cylinder head. Water will always get in the oil because of crankcase condensation, unless you have a case drier or desiccant.

You mention you have noted moisture and oil at the vent tip, if your vent is long it will be cooler after shut down than the engine vapors and can condense moisture at the tip. It doesn't necessary mean you haven't removed the water in the oil. After condensed water is removed from the oil, the "cruise" vapors are from ring blow by which is huge in comparison. In flight freezing of vent tubes can be an issue because of this. Some airplanes have whistle slots, insulation or heaters to prevent this.

Your aircraft picture looks fantastic, do you have new baffles, maybe the cooling air is better and thus cooling your tube more and now you notice the moisture at the exit? New or longer tube, different exit location that might be cooler?

Mark

[Mark Bowden]

Re: Engine Not Coming Up to Temperature

If you want a simple test for moisture in oils, an accepted practice is the Crackle Test. Take a very small oil sample, shake vigorously and put one drop on a hot plate at 130 deg. Centigrade. If it "crackles" (like bacon hitting a frying pan) you have water. Only hopefully not that bad!

This is a go-no-go test but if you watch and see few bubbles it is somewhere around 500-1000 ppm, crackles are about 2000 ppm with more and larger bubbles. A simpler field method after flying is drip a drop on the exhaust tube. If you don't want oil on the exhaust, put a drop or two in a spoon or in piece of foil over a candle or lighter, be careful. If it just sits there with no bubbles or smokes there's no water.

Mark

[Scott]

Re: Engine Not Coming Up to Temperature

From a Parker article( available at www.kittiewake.com):

Water in oil can exist in three stages: dissolved, emulsified and free. Below saturation level, the
molecules of water are dispersed alongside oil molecules, resulting in water in the oil that is not
visible. This is known as dissolved water, the least dangerous water state to a lube system.
When the amount of dissolved water exceeds the saturation point, the oil is no longer able to absorb
more water molecules, resulting in emulsified water. This is characterized by a hazy or cloudy
appearance of the oil.

Further increments of water content in oil will result in separate levels between oil and water
forming. This state is known as free water. Due to its higher density, the water forms the lower layer,
settling at the bottom of the sump, with the oil floating on top. However, emulsified water will also
be present in an intermediate phase, continuing to circulate in the lube system.

synthetics are capable of dissolving more water. A mixed blessing perhaps. I have no first hand experience with Exon Elite but I'm sure its a fine oil. I've always used Shell 15W50, also a semi synthetic, and always happy with the way it handles extremes of ambient conditions.

I raced once or twice in Marshalltown and remember both the humidity and the corn!
Based on this discussion Marty it seems you're in good shape. Water out of the breather is not a problem, oil looks good, and engine is otherwise strong. Short of more frequent oil changes or using one of those crankcase/venting/dehydrating devices, not sure there's anything for you to fix.

[dkenney1]

Re: Engine Not Coming Up to Temperature

I know I'm a little late to the dance on this thread but the topic was of interest since my C85-12 is very slow to come to 75 degrees even in 80 plus degree summer weather. Once flying, regardless of how hard or easy I take on it the highest temp I've seen is 185 at 1000' AGL. Usually oil temp is in the 150 to 170 range. At annual I asked the A&P/AI about it and they thought that was really good for the old engine with 130 SMOH. "I'd rather see a good margin from redline" is what I was told. His experience was those that run much higher than that regularly also seem to need top overhauls sooner, which to him meant bad airflow/cooling in the cowl.

Like most things though I assume I could ask another A&P and he'd say the opposite.