Lycoming - Continental Question

Ventucky Red

Ventucky Red

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Looking at the Lycoming 0-235 and the Continental 0-200-A engines, which of them has it where the crank and the cam are bathed in oil while sitting?

From my Tomahawk days, I was told this is true for the 0-235 hence one of the reasons for the 2400 TBA. But yesterday I was told this is not so, now I am confused and Mr. Google is not helping me.

Thank you for the info
 
Neither are in an oil bath when sitting.

Continental = camshaft below crankshaft

Lycoming = camshaft above crankshaft

Both engines suffer from cam & lifter problems.
 
When you overfill them?
 
Dave Arata said:
Have you asked Mrs. Google? She knows everything. :D
Click to expand...

She is still ****ed off with me from that little incident with her sister at their wedding after she told me under no circumstances yada yada yada......

bnt83 said:
Neither are in an oil bath when sitting.

Continental = camshaft below the crankshaft

Lycoming = camshaft above the crankshaft

Both engines suffer from cam & lifter problems.
Click to expand...

Thanks, this is what I was looking for..
 
Lycomings have a reputation for camshaft corrosion in engines that sit unflown for long periods. It doesn't seem to be reported as much with respect to Continentals, and some point to the difference in camshaft location as the reason.
 
Dana said:
Lycomings have a reputation for camshaft corrosion in engines that sit unflown for long periods. It doesn't seem to be reported as much with respect to Continentals, and some point to the difference in camshaft location as the reason.
Click to expand...
It happens in Continentals, too. But in the Lyc, that cam is up high and very close to the top of the crankcase. When someone uses a sump heater, any moisture down there gets vaporized and it rises and condenses on the cold stuff up top, including the camshaft and lifters.
 
Wouldn’t the heat rise along with the vapor and Heat the Cam etc. Particularly in

a cowled engine with a blanket cover?

Could a difference in the materials between brands play a role?
 
Magman said:
Wouldn’t the heat rise along with the vapor and Heat the Cam etc. Particularly in

a cowled engine with a blanket cover?

Could a difference in the materials between brands play a role?
Click to expand...
The heat rises all right, but it is wicked out via the cold case walls. So the top is colder, because only the sump is heated. A car warmer inside the cowling heats the entire engine from the outside, meaning that it gets plenty warm up top, discouraging condensation on anything inside the top of the case.

Cams and cranks are made of high-carbon alloy steels. That stuff corrodes more easily than low-carbon stuff. Not sure of the electrochemistry there, but I've seen it.

Then they're mounted in dissimilar metals. The crank is in lead/tin/copper-lined steel bearing shells. The cam runs directly on the crankcase aluminum/magnesium. Get a bit of moisture in there and you have electron flow that breaks down the oil and combines it with H and O from the water, and you get acids.

Lycoming and Continental have been building this stuff for a long time. If there were alloys that were much more corrosion resistant, yet at least as strong and resilient, they'd be using them.

Everybody worries about the cam, but I have seen serious cylinder wall corrosion and rusted gears in the accessory case. These are also fatal to engine life. The piston is a high-silicon aluminum, running in a 4130 chromoly steel cylinder. Moisture gets in there too, and causes cylinder pitting, which accelerates the cylinder wear as the pistons run across those pits, and the engine starts using oil and making metal. Those pits harbor a lot of oil that then gets burned when the cylinder travels downward on the combustion stroke.

Moisture in the sump corrodes it. The thin stamped-aluminum sumps on the big Continentals are known for corroding right through.
 
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Magman said:
Wouldn’t the heat rise along with the vapor and Heat the Cam etc.
Click to expand...
"Heat" doesn't rise. Hot air does... hot humid air, that then hits the top of the cooling case, where the moisture condenses out and drips onto whatever is below it.
 
The whole problem would mostly go away if people would just stop operating their aircraft engines like they do their cars. Short runs, or just ground-running and then putting the airplane away, is what puts most of that moisture in there and allows it to stay there.
 
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