High Oil Temperature

[blitz1.5]

Has anyone seen piston ring blow-by cause oil temps to climb to the redline during a shallow climb in OATs around 65 degrees?  My D model has a freshly field O/H'd engine...not sure about the quality of the O/H.  I've checked the vernatherm (seems to work correctly), the oil cooler was flushed, oil pressure is good, temp gauge seems to work correctly.  I'm getting considerable amount of black exhaust on the right gear door and oil spray from the breather tube on the left gear door after each flight.  I'm also noticing a vibration that seems to be increasing.  I'm considering pulling all four cylinders and having a different mechanic O/H or replace them as necessary.  Does anyone have thoughts before I put so much more money and effort into the engine?  Oh yeah, the compressions are 79 on the 2 steel cylinders and 73 on the 2 channel chromed cylinders and my current mechanic says they probably got glazed from too much ground running (over an hour before the first flight)

[carusoam]

Welcome aboard Blitz.

Do you have an engine monitor?

Can you post the graphs?

These things can be very helpful for your situation.  All the data together can really generate a picture for some of the people around here....

1) if you are experiencing blow by, expect the oil to become very dirty very quickly.

2) the oil will smell like exhaust.

3) the engine case gets pressurized and sends excess oil out the vent.

4) what does your oil say?

Best regards,

-a-

Edited March 22, 2017 by carusoam

[bonal]

During your compression test listen through the oil adder tube if you have blow by into the case you will hear it. My factory gauge was off (high) by 20 degrees but my oil temp does run a bit high. 

[Guest]

Pull the spark plugs and look at them as well bore scope the the cylinders.  The faulty one should evident by the burned and blackened piston crown and spark plugs.

Clarence

[blitz1.5]

Alright, unfortunately I don't have an engine monitor.  I tested the temp gauge with boiling water.  It read about 220, so just a little high.  It is well connected and seated in the oil filter adapter.  On the last flight I had 7-1/4 qts of oil before and 6-3/4 qts after a 45 min local.  Also, the oil cooler was at 150 degrees a couple minutes after shutdown.  

The oil is fairly black after only about 3 hours since changing it and I would say it smells like exhaust.  Also, the chrome cylinders read at least 25 degrees hotter than the steel after shutdown...I checked with a laser thermometer.

On the compression check, air was escaping from the oil dipstick tube notably for the chrome cylinders.  The boroscope did not reveal anything but all the spark plugs get black and full of deposits fairly quickly.

Thanks for y'alls interest,

Will

[Andy95W]

I think I would be looking at the feasibility of swapping out the two chromed cylinders for two overhauled nitrided ones.

When the (different) mechanic pulls the two chromed cylinders, he should check that the proper rings are installed.  They are different for chrome vs. nitride cylinders. If the overhauler installed the wrong rings in the chrome cylinders, the result would be similar to what you're seeing.

[carusoam]

Another thing to read about here...

Oil level in Lycoming O and IO360s.

There is a bit of a penalty for adding too much oil.  The excess gets blown overboard out the vent.

This is a completely different issue, but something to be aware of.  It is simply a volume of the oil pan is smaller than what Lycoming accidently advertises(?)

From old fuzzy memory...

1) min oil level is about 2 qts.

2) normal oil level is about 6 qts.

3) maximum oil level is about 7qts. But the 7th quart doesn't stay in the engine very long...

4) usual experience for this engine is it actually uses a quart of oil every ten hours or so. Expect to put a quart in somewhere around 8 - 10 hours... fill it back to the 6 quart line.

5) measuring / graphing the oil being used over time, you may see the first quart getting used very quickly, the next quart dissapears at a slower rate, the third quart gets used at the same rate as the second.  The useage rate levels off.  This is a sign that oil is venting overboard. 'Normal venting' of oil slows way down below the 6qt line.

6) a quart of oil venting overboard leaves a bit of a mess behind starting at the vent drain tube near the cowl flaps.  The oil Then runs back along the bottom to the tail.

7) Other things to read up on are chromed cylinders... why they were done and why they are not so popular anymore... See if it is possible to determine if there are any steps formed near the top of the cylinder where the piston travel ends.  If the cylinder was broken in one way, the step forms, things change... the piston tries to cross the step at high power resulting in damage or wear to the ring... once the ring is worn or damaged blow-by is a high probability

8) to get a good visual of the cylinder walls look up video cameras around here. They go down a spark plug hole and find all kinds of things like the surface of the cylinder walls, valve issues, and piston cleanliness...

9) read up on the history of your engine in your engine log.  See what and when the cylinders were replaced.

10) there is some discussion around here of what to look for in worn cylinders.  Cross hatch patterns vs. worn smooth. Pockmarks and craters caused by surface rust. That kind of thing.

11) so why does everyone put 7 quarts of oil in at first...  oil serves two functions, lubrication and it's a cooling fluid... more oil is better for cooling.  If all of your oil is going overboard, you will see the oilT rising as the oil level goes down...

12) there are a lot of used JPI engine monitors hitting the market at great prices.  This is being driven by people upgrading to the newer color and more talented devices... we have an MSer that sells these devices around here somewhere...

PP ideas only, not a mechanic...

Best regards,

-a-

Edited March 22, 2017 by carusoam

[FloridaMan]

If your oil temp is high and oil pressure looks good and you're using the original "6 pack" of gauges, turn the master off and see if the oil temp gauge goes to zero. If it doesn't, push on it firmly with your thumb and see if it the temperature looks good. That happened to me; ended up being a bad connection on the instrument and the final straw to justify buying an EDM-900. 

[Guest]

The black burnt smelling oil is a sure sign of blow by from the rings.  Chromed cylinder walls are generally known for poor breakin with resultant blow by and higher oil consumption.  Dirty car boned oil flowing through your engine can't be good.

As Andy says above look at replacing those cylinders with nitrite steel.

Clarence

[blitz1.5]

I changed the cylinders to new Millenium steel.  I've flown a couple hours so far and  the oil temp was nailed at 200 degrees...even in the climb.  Thanks again for y'alls input!

[carusoam]

The awesome power of the MS community!

-a-