[STEVE]

STEVE on September 7, 2022 at 9:56 am #21527

Hi Charlie;
So I can get a better idea of the circumstances of your high OT, I’m going to ask some questions:
Are these high oil temperatures a new thing?
Are the oil temps “normal” during months when the OAT is lower?
When you say a cylinder wall is glazed; how do you know this? Have you visually checked out the appearance of the cylinder walls with a borescope?
What is your oil consumption?? Hours/quart?
Has the oil consumption increased recently?
What is your idling oil pressure?
What is your cruise oil pressure?
What oil level are you running your engine?
I feel like you leaning method is as good as you’re going to be able to do with a carbureted engine. The distribution of the fuel air mixture is too varied between cylinders to safely run LOP.
One thing some pilots believe is that it’s cheaper to buy gas than cylinders; therefore they choose to run their engines very rich. This has a tendency to bring down temperatures, but it’s not the ideal way to run your engine.
It sounds as though you have already done the easy stuff.
The questions, especially the idling oil pressure question is to determine if there’s excess wear in the bottom end of your engine.
Are there any other symptoms you can tell me about. Does the engine stutter a little bit in the morning before all cylinders are running smoothly?
Please get back to me with answers.
Thanks
Steve

[CHARLIE MUELLER]

CHARLIE MUELLER on September 6, 2022 at 7:09 pm #21525

Steve-

I own a Piper Dakota with a O-540-J3A5D engine. The serial # is L-21175-40A.

It was installed in June of 1993. It has 1, 980 hrs and a mix of chrome and nickel cylinders.

Compressions good, oil consumption is good but oil temps are 215 +|- with as high as 233 in the initial climb. I just had a new oil cooler installed as the previous one was cracked.

I do have a cylinder that is glazed presumably from improper break in from the previous owner/not sure if that is a cause of heat.

I’m hoping you can help me with any of the following questions.

1.) How can I get the oil temps down into the normal range?
I’ve done all of the tests putting a light in the lower compartment and looking for gaps, etc. I’ve made some minor tweaks to the baffling.

2.) Can I run this engine LOP? 2.a)Can I simply lean until roughness and then enrich to where it runs smooth? That seems a lot simpler than using my engine monitors. I talked with Lycoming about leaning and they said not to use LOP IN carbuerated engines.
Some of my flying is for the Coast Guard Auxiliary -Naples to Tampa 3 hr patrols at 1,000’. Its hot and I typically fly at 65%power and lean to 12 gallons per hr. Do you have any suggestions for engine operations in this profile?

Thank you-

Charlie