High oil temp on new engine

Received new 370 Stroker engine. Installed on my -8A and made three flights .... all lasting five minutes as the oil temp never stopped rising. Landed at 230 but did not keep flying to see where it would end up. Removed engine when could not find the problem and put original back on.

Drained oil and in only 15 minutes it was already dark. Would assume excessive blow by? Pulled cylinders one by one to inspect for broken rings or scuffed piston. Cylinders are 9:6:1 steel. Nothing!

The oil cooler is the big cooler for the -10. Keeps temps in the 170s on the current 0-360.

Shop said check the vernatherm. But I am using the same one on the current 0-360 and it works like a charm. I am lost at what to look for. This is not a warranty situation so going back to mfg is not an option.

Several shops want to do a tear down but I am hesitant to do a tear down on an engine with only 15 minutes of flying. It was run in the dyno and was supposedly okay.

Thoughts?

Does the new engine have oil squirters installed where the old one doesn't?

How about ignition timing? Is the new engine a 20* BTC engine and the old one a 25* BTC engine? If so, are you using your same LightSpeed flywheel with the fixed magnet? That could cause it, that and the break in heat of a new engine.

Do you have a spare temp probe and a spare display function? Verify that any oil is even flowing through the cooler. +1 on the timing check.

oil

Check the oil filter, screen to be sure no major damage is occurring. Timing like the others said. Find a good borescope to check cylinders if it continues.

Did you build the engine? Is it set up with spec piston/cylinder clearance?

Turning it over by hand with the plugs out can tell you if the friction seems too high. Most likely the rings seating, but not a sure thing.

Fly on a cool day?

Len---check to see if the gasket at the vernatherm is blocking the outlet. Have oil in the cooler hoses? If the other engine runs cool, then something not right here.
Tom

Len,

What do you have:

Cowl
Plenum
Exhaust 2 or 4

Sounds like exit area is too small.
Problems with -A models

HUM-----prior engine had no such temp problems. This one shares some of the same accessories. That leads me to think there is something with this engine.
Tom

Did the build include the 'New and Improved' Lycoming 'hyperbolic' flat tappet lifters? If so, that could be the problem.

I had my o-320 overhauled about three years ago now, and fought high temperatures, high oil usage and dirty oil. My engine came out twice for inspection and disassembly before the problem was solved.

It seems that the 'New and Improved' lifters allowed too much oil to bypass the lifter bodies, flooding the tops of the cylinders with oil down the pushrod tubes; the drainbacks were unable to cope with the flow, and the intake valves happily sucked up whatever they could.

A change to conventional old-style cylindrical lifters solved the problem, and the engine has performed flawlessly ever since.

I was told that Lycoming denied any knowledge of the problem.

Maybe others can chime in as this is my first experience with aviaion engines and my plane has only 3 flights, but 5 minutes sounds too short to get 6-7 quarts of oil to 230 degrees, especially with a working cooler. I just don't see how your engine can generate that much heat without a SERIOUS friction generating source. I have a 400 CID hot rod that produces 525 HP. Even if I run it hard, it takes 10 minutes to get my oil up to 80C on a summer day. That engine only has a 5 quart capacity. Yes, air cooled engines rely more on the oil for cooling, but not that much more. My air cooled Porsche takes 15 minutes to get 8 quarts up to 200 and it produces close to twice the HP of your engine.

The first place that I would be looking at is the COMPLETE oil system. Either your engine is not using all of the oil in circulation or a problem with flow. Maybe blockage somewhere, including the cooler and it's routing. I would also be HIGHLY suspicious of the oil temp sensor. Very easy to drop it in boiling water and measure the resistance to confirm it's readings. Also easy to do the same with the vernatherm.

also, 230 is no big deal for oil and doesn't constitute a reason for immediate shut down. Most oil is fine up to 275. It may take some life out of it, but quite unlikely to break down. It may get thinner, but won't evaporate. I would run it longer than 5 minutes to see what is happening. You could have a sticking vernatherm that will eventually open.

Last, I pulled my filter after the first hour and a half on my rebuilt engine and hte oil was already getting dark. This is normal due to the excessive blow by in a new engine that is being run very rich. Look at your tail pipes. If you have been running full rich, as suggested, you're getting a lot of carbon soot. That same soot is in the blow by gasses as well.
Larry

Glovebox said:

Did the build include the 'New and Improved' Lycoming 'hyperbolic' flat tappet lifters? If so, that could be the problem.

I had my o-320 overhauled about three years ago now, and fought high temperatures, high oil usage and dirty oil. My engine came out twice for inspection and disassembly before the problem was solved.

It seems that the 'New and Improved' lifters allowed too much oil to bypass the lifter bodies, flooding the tops of the cylinders with oil down the pushrod tubes; the drainbacks were unable to cope with the flow, and the intake valves happily sucked up whatever they could.

A change to conventional old-style cylindrical lifters solved the problem, and the engine has performed flawlessly ever since.

I was told that Lycoming denied any knowledge of the problem.

Click to expand...

This is a good example of what I was referring to. The rocker cases are holding half the oil and your cooling capacity is cut in half because the oil volume is cut in half.

Larry

Larry----I think that Len says his oil is getting dark indicates that is IS hot, and not an instrumentation issue. Gee I wish it was instrumentation, but I fear not.
( He's had enough engine issues to last a lifetime!)
Tom

TS Flightlines said:

Larry----I think that Len says his oil is getting dark indicates that is IS hot, and not an instrumentation issue. Gee I wish it was instrumentation, but I fear not.
( He's had enough engine issues to last a lifetime!)
Tom

Click to expand...

He should do a bit more research here. I don't believe oil gets dark from heat and I can't think of a single engine oil manufacturer that would claim any type of break down based upon 60 -120 seconds of running at 230 degrees. Most spec their oil to 250 or 275 before any breakdown (other than viscosity breakdown). occurs. Dark can come from many things, but excess carbon is certainly one of them and running filthy rich creates a lot of carbon. New engines have a lot of blowby in the first few hours this carbon makes it to the oil. The oil that comes out of the diesel in my sailboat is black as night and is completely normal. It is carbon soot that gets scraped off the walls after combustion and mixed with the oil. The oil has additives to hold it in suspension.

Larry

Oil can definitely get dark from getting too hot (I have seen it happen in just one flight... comes back black and smelling like burnt toast), but I agree, 230 is not near hot enough to cause that. Would have to be 275+

The other problem that can cause oil to darken quickly and cause high oil temps is combustion gas blow by. It contaminates the oil turning it black and causing unintended heating.

temp

If oil is 230 at cooler it could be 270 in engine had that happen when I started out with small oil cooler at break in and the engine quit on roll out from vapour lock of fuel I would make a 90 degree bend and put it on cowl exit with a 1" lip and see if oil temp goes down if it does you need more exit air
Bob