O-235 L2C Oil Temp & Pressure

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John Henry

Filing Flight Plan
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Jan 28, 2022
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John Henry
Hello everyone,
I am new to the forum and a Tomahawk owner with questions on maintenance issues.
I recently had the engine overhauled with new cylinders, pistons, seals and bearings.
The crank and cam were cleaned and resurfaced.
My first flight consisted of 1hr at 75% power at 3000ft for 1 hr.
Oil temp climbed up to 240 and oil pressure dropped to 35-40psi for flight.
Ambient temp was 65 degree F.
Is this temp and oil pressure normal for the breakin period of the engine?
Kind of leary to fly it again at that low oil pressure.
I have heard different theories on whether this is normal or not.
Anyone have any expert advise?
 
upload_2022-1-28_16-24-55.png

From the O-235 and O-290 Operator's Manual: https://www.lycoming.com/sites/default/files/O-235&O-290 Operator Manual 60297-9.pdf
Page 3-7.

Oil temp is typically high for the first few hours. Friction does it, as parts are mating. Especially the rings and cylinders. That oil pressure is much too low, and the problem is likely in the pressure relief valve. A mechanic could adjust it, if it's adjustable. Some need shims put under the spring inside it to raise the pressure. Or, there could be some debris caught under the ball, interfering with its seating and allowing too much oil to dump into the crankcase and lowering the pressure.
 
Thanks Dan, I found the o-235 Operators Manual this afternoon after I posted my question. I will get with an A&P to look at the relief valve adjustment. Is it possible as well to have the suction screen plugged up this early as well?
 
I believe the the L2C is unique is needing a sort of metering plate in the oil filter area.
 
Thanks Magman.
I was hoping and assuming the shop that rebuilt the engine put it back in, but I probably shouldn't assume anything and just check it out as well.
Thanks again.
 
My Tomahawk had higher oil temperatures than I liked, but not in 65F weather. If your oil temperatures are really that high, you need to understand why and correct the issue. Does your Tomahawk have the little cooling can that goes around the oil filter?

This: https://www.ebay.com/p/3039627495
 
John Henry said:
Oil temp climbed up to 240
Click to expand...
Dan Thomas said:
Oil temp is typically high for the first few hours. Friction does it, as parts are mating. Especially the rings and cylinders.
Click to expand...
Typically high is understandable, but I am reading oil temp should be limited to 200 during break in. One can limit climbs, try to break in during colder days, run rich, run fast, limit drag, etc but when break in instructions say limit temp to 200 and actual temp goes higher, what is the pilot to do?
 
kyleb said:
My Tomahawk had higher oil temperatures than I liked, but not in 65F weather. If your oil temperatures are really that high, you need to understand why and correct the issue. Does your Tomahawk have the little cooling can that goes around the oil filter?

This: https://www.ebay.com/p/3039627495
Click to expand...
Thanks Kyleb. Yes my engine has the cooling cover for the oil filter. Also have all new baffling as well which is tight. Going to drain the oil and change the filter to make sure the screen is clear as well.
 
FORANE said:
Typically high is understandable, but I am reading oil temp should be limited to 200 during break in. One can limit climbs, try to break in during colder days, run rich, run fast, limit drag, etc but when break in instructions say limit temp to 200 and actual temp goes higher, what is the pilot to do?
Click to expand...
Where do you read that?

Here's the Lycoming instructions for test flights after field overhaul: https://www.lycoming.com/sites/defa...ating engine Break-In and Oil Consumption.pdf

They do not mention oil temperature. An older version of that document only said to keep the pressures and temperatures within limits. Max oil temp for that engine is 245°F. From the O-235 operator's manual:

upload_2022-1-28_20-13-51.png

Keeping a rebuilt engine down to 180 would be difficult in warmer weather.

I always tested the temp gauge for accuracy when replacing an engine. One doesn't need false indications. I had one, an O-320 in a 172, that would not stay within the green. I found that the oil cooler had accumulated varnish on the inside over the years, effectively insulating the oil from the cooling channels. It would not wash out. A new cooler fixed it.
 
John Henry said:
Is it possible as well to have the suction screen plugged up this early as well?
Click to expand...
I sure would hope not. There's also the suction screen in the sump.

Low oil pressure can result in high oil temperature.
 
Maybe I missed it but I didn’t notice your oil pressure prior to flight.

35 is well below the minimum of 60. I would believe the gage and not fly until

you sort things out.
 
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