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More new owner questions - oil pres/Temp M20E


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Hey everyone! 

 

I'm back with more new owner questions for my 66 E model. I posted a few weeks ago about what appeared to be a misaligned exhaust tailpipe and got great answers - my IA took quick care of it based off the help provided here.

 

The question(s) I have today concerns the state of my oil, particularly in climb. I'm running Aeroshell W100 and keeping it between 5.5-6 quarts based off advice from the previous owner.

Here in MO right now most days are in the mid 90s or even around 100. During climb at 25 Inches (or best available), 2500 RPM, and cowl flaps open, and climbing at 120MIAS - I'm seeing oil temps exceeding 210 and even flirting with the yellow. At the same time oil pressure is consistently flirting with the bottom of the green at 55PSI. This is causing me some concern. CHTs and EGTs look peachy.

Once I cruise out at altitude the oil usually stabilizes at about 175F and pressure at about 65 PSI.

Should I be having cause for concern right now, maybe ask to have the oil pressure regulator adjusted? Change oil type? Accept this is how it is when it's this hot out?

 

Thanks in advance for your fantastic information.

 

- Andrew 

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There is another thread going on oil pressure.  After you verify the accuracy of the current gauge, have the pressure adjusted to 80+/- psi. Check that the top and bottom of the oil cooler is sealed to the mounting bracket on the cowl with some rubber weather stripping.

Clarence

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IMHO I would listen to the advice of the engine manufacturer, start by operating at 8 quarts and plot how long and how much blow by is occurring. The engine requires

a minimum quantity to achieve its intended purpose. Oil does 2 things lubricate and provide a means of transferring heat.

 

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My 325 hr factory rebuilt IO-360-A3B6 reads 77-78 psi on the new G3X EIS at cruise. It often goes to about 91 momentarily during takeoff. Lycoming test cell data showed 83.6 during a 15 min full power run-in (limits were listed at 75-85).

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The Lycoming field rep told me it was fine to run an IO-360 between 5 and 7 qts.  Min oil allowable is 2 qts. When I bought the airplane the engine (since replaced) was burning about 1/2 qt per hour and on one flight I let it get down to four and the oil temperature started to rise and the pressure dropped slightly. Based on the recommendation and experience, I don't let it get below 5. Actually, I've always run Lycoming 360s between 6 and 7. Lately I've been running between 5 and 6 to see if it made any difference in the amount blowing out on the belly. It's a factory rebuilt with 325 hrs and it doesn't blow out much oil and so far I'm not noticing much difference. It uses about a quart every 12 hours.

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1 hour ago, M20Doc said:

There is another thread going on oil pressure.  After you verify the accuracy of the current gauge, have the pressure adjusted to 80+/- psi. Check that the top and bottom of the oil cooler is sealed to the mounting bracket on the cowl with some rubber weather stripping.

Clarence

Thank you I'll check that out! Would bringing the pressure up using the adjustment also help with the temperatures? Or rather, should it?

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13 minutes ago, Mortarion42 said:

Thank you I'll check that out! Would bringing the pressure up using the adjustment also help with the temperatures? Or rather, should it?

Lower oil temperature on start up(cold oil) will result in higher oil pressure.  Increasing the oil pressure should have no effect on temperature that I’m aware of.

Clarence

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37 minutes ago, Jpravi8tor said:

IMHO I would listen to the advice of the engine manufacturer, start by operating at 8 quarts and plot how long and how much blow by is occurring. The engine requires

a minimum quantity to achieve its intended purpose. Oil does 2 things lubricate and provide a means of transferring heat.

 

It does a few more things as well.  Lubricates moving parts, cools the engine, cleans the engine, seals gaps in parts, and actuates the prop and protects from corrosion.

Clarence

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5 hours ago, Mortarion42 said:

The question(s) I have today concerns the state of my oil, particularly in climb. I'm running Aeroshell W100 and keeping it between 5.5-6 quarts based off advice from the previous owner.

I realize I'm probably opening up a debate, but....

There is plenty of talk about adding 7 quarts at an oil change, then not adding anything until getting down to 5 quarts because "anything over 6 quarts just quickly blows out onto the belly." I read all those posts when I bought my plane and operated that way for a number of years after getting my M20D with the O-360 in it. I keep a spreadsheet of all my flights and monitor a number of things in the sheet based on the tach times, one of which is the amount of time between adding a quart of oil between oil changes.

I started questioning why I could add 7 quarts during an oil change and typically go around 10 hours before getting down to 6 quarts? The more I thought about it the more it didn't make sense. How would the engine know the difference between having just done an oil change so "I'd better not dump a quart onto the belly to get down to 6 quarts" as opposed to "It's been 20 hours since the oil change, I'm going to show that pilot who's who and dump oil until I get back down to 6 quarts."

I started adding a quart of oil when I got to 6 quarts on the dipstick instead of waiting until I was at 5 quarts on the dipstick and then monitored the use. Guess what happened? Over the next 200+ hours of flying and multiple oil changes there was no difference in the time between adding a quart of oil at 6 on the dipstick compared to the previous couple hundred hours of adding when it got to 5 on the dipstick.

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1 hour ago, M20Doc said:

Lower oil temperature on start up(cold oil) will result in higher oil pressure.  Increasing the oil pressure should have no effect on temperature that I’m aware of.

Clarence

So in other words, if I bring the pressures up a bit, but the temps still climb above 200 or 210 curing the summer climb - not much to worry about?

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New aircraft new owner new operating techniques start from a baseline and plot your results, there is definitely a correlation between pressures and temperatures. M20Doc definitely has the sage advice when it comes down to it but…..oil is a cheap Insurace to guarantee your engine is operating at its peak performance. If you add oil is it not taking contaminants with it as its blown by? Is it not scavenging the dreaded sludge from the galleries and prop? 

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1 hour ago, Mortarion42 said:

So in other words, if I bring the pressures up a bit, but the temps still climb above 200 or 210 curing the summer climb - not much to worry about?

As with all things, verify the data first, for both pressure and temperature.  You can boil the oil temp probe in water to see what the gauge shows, you can verify the oil pressure with a known test gauge plumbed into the system in parallel with the ship gauge.  Once you know your readings are legitimate you can decide how to proceed.

Clarence

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2 hours ago, Mortarion42 said:

So in other words, if I bring the pressures up a bit, but the temps still climb above 200 or 210 curing the summer climb - not much to worry about?

One other question… you said your CHTs in climb were “fine”, but the  lyc redline is 475, which is generally considered much too hot.  How hot are they during climb?  Most folks climb at ~120mph and rich enough to keep CHTs below roughly 400 (or a little less).

Edit: should have finished my thought… higher CHTs may result in higher oil temps which results in lower oil pressure.  Control CHTs, both symptoms are fixed.

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Andrew,

Did you forget to mention the details of your climb?

Rags pointed out an important issue above…

 

OilT is going to be a cumulative affect of heat going in, and heat coming out of the oil….

The oil hits a peak temperature where it is cooling the hottest parts of the engine… exhaust valves and turbo parts…

Power settings, leaning 2-300°F ROP, air speed….

 

Often people use power settings and air speed to control CHTs….

Controlling OilT is often a discussion of oil cooler status and vernatherm health….

 

Welcome to getting to know your plane!

Best regards,

-a-

 

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36 minutes ago, Ragsf15e said:

One other question… you said your CHTs in climb were “fine”, but the  lyc redline is 475, which is generally considered much too hot.  How hot are they during climb?  Most folks climb at ~120mph and rich enough to keep CHTs below roughly 400 (or a little less).

Edit: should have finished my thought… higher CHTs may result in higher oil temps which results in lower oil pressure.  Control CHTs, both symptoms are fixed.

I want to say the CHTs say below 400 in climb but I cannot reliably answer that at this moment. I'll take some notes during my next flight and adjusting mixture as needed, thank you! Will also be verifying that the prob read is accurate.

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Hey everyone! 
 
I'm back with more new owner questions for my 66 E model. I posted a few weeks ago about what appeared to be a misaligned exhaust tailpipe and got great answers - my IA took quick care of it based off the help provided here.
 
The question(s) I have today concerns the state of my oil, particularly in climb. I'm running Aeroshell W100 and keeping it between 5.5-6 quarts based off advice from the previous owner.
Here in MO right now most days are in the mid 90s or even around 100. During climb at 25 Inches (or best available), 2500 RPM, and cowl flaps open, and climbing at 120MIAS - I'm seeing oil temps exceeding 210 and even flirting with the yellow. At the same time oil pressure is consistently flirting with the bottom of the green at 55PSI. This is causing me some concern. CHTs and EGTs look peachy.
Once I cruise out at altitude the oil usually stabilizes at about 175F and pressure at about 65 PSI.
Should I be having cause for concern right now, maybe ask to have the oil pressure regulator adjusted? Change oil type? Accept this is how it is when it's this hot out?
 
Thanks in advance for your fantastic information.
 
- Andrew 

I think there are a few other things to look at. I found as oil ages, you will see slightly higher oil temps and lower pressures. You didn’t mention how many hours you have on the oil.

Also, I found that on really hot and humid days, raising the climb speed 5 knots can help a bit with high oil temps. If you told us that your oil temp stays high during cruise, I’d be looking for other factors. But it really sounds like a hot/humid climb situation - that is unless you come back and say your cylinders are at 450°


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13 hours ago, Mortarion42 said:

I want to say the CHTs say below 400 in climb but I cannot reliably answer that at this moment. I'll take some notes during my next flight and adjusting mixture as needed, thank you! Will also be verifying that the prob read is accurate.

Also adjust your climb speed to 120mph as @Marauder mentioned.  It makes a big difference.  If you need Vy or Vx right after takeoff for some reason, do that, but use ~120mph after obstacles aren’t an issue.

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For a reference, i flew today and was watching some numbers. I have the big guppy mouth on my E still, 1965 model. I will ALWAYS have a minimum of 6qt of oil before i take off. As the POH for mine says, if you see it below 6qt, add oil to bring it to 7. Im using about a quart every 6-8 hours right now. 

 

Taking off from 104F field today at 4200DA. I saw 190F and 80psi in the climb. CHTs peaked on the JPI around 360 and once in cruise oil stayed at 190F and psi fell to 70psi. CHTs went down to 320F. I climb at 110-120mph at 25/25, opening up the ram air when mp falls bellow 22. I only see oil pressures in the yellow arcs during idle ops or at first start up, which is in line with the POH. 

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Don’t pull the prop back to 2500 RPM, leave at 2700 leave the throttle full open, and climb at  a higher speed like 140 mph. All these things will get you to altitude  sooner, cooler and more efficiently  and then the cruise portion begins, where your temps are lower and pressures are higher also.

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  • 1 month later...
On 7/19/2022 at 9:39 PM, jetdriven said:

Don’t pull the prop back to 2500 RPM, leave at 2700 leave the throttle full open, and climb at  a higher speed like 140 mph. All these things will get you to altitude  sooner, cooler and more efficiently  and then the cruise portion begins, where your temps are lower and pressures are higher also.

Sorry for the late follow up, but I just wanted to say this helped a ton. I had my IA dial up the pressure adjustment a smidge, and now climb at 2600 and 130 - 140. Temps and pressures are happy as a clam, as am I.

 

Thanks!

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On 7/17/2022 at 8:00 PM, Jpravi8tor said:

New aircraft new owner new operating techniques start from a baseline and plot your results, there is definitely a correlation between pressures and temperatures. M20Doc definitely has the sage advice when it comes down to it but…..oil is a cheap Insurace to guarantee your engine is operating at its peak performance. If you add oil is it not taking contaminants with it as its blown by? Is it not scavenging the dreaded sludge from the galleries and prop? 

Consider this.  When there is blowby, combustion is forcing combustion byproducts past the rings into the crankcase.  Combustion byproducts are contaminants in the oil.  Also, if there is blowby, it creates pressure in the crankcase which is what forces it out of the draft tube underneath your plane.

So……… the contaminants end up in the crankcase.  Yes some of the contaminated oil exits the crankcase, but wouldn’t it be better for the contaminants not make it to the crankcase?

BTW, I have always agreed that oil is cheap insurance and is much cheaper than engine overhaul.

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