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Connecting Rod lubrication

chiricuca

Active Member
My colleage is worried about the aspect of connecting rod in two rear cylinders (3 and 4). He consider that is not enough lubrication at this point and is proposing me to make a hole in the top (1 or 2 mm) to let the oil fluid there. As I don't understand a lot about and I'm affraid to "touch" this important component of the engine, I would like to know if the gurus of Lycoming can give me their oppinions about. The engine is Lycoming O-320-D1A with 300 hours aprox.
In one of the picture I marked with an arrow the point in which he wants to drill the hole.

https://flic.kr/p/2mX1ogC
https://flic.kr/p/2mWZPmY

Your comments will be very appreciated. Thank you.
 
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My colleage is worried about the aspect of connecting rod in two rear cylinders (3 and 4). He consider that is not enough lubrication at this point and is proposing me to make a hole in the top (1 or 2 mm) to let the oil fluid there. As I don't understand a lot about and I'm affraid to "touch" this important component of the engine, I would like to know if the gurus of Lycoming can gice me their oppinions about. The engine is Lycoming O-320-D1A with 300 hours aprox.
In one of the picture I marked with an arrow the point in which he wants to drill the hole.

2mWZPmY

2mX1ogC


Your comments will be very appreciated. Thank you.
Hola, no tengo foto...
 
Oil squirts

From the pictures it looks that the engine is prepared for the mounting of
oil squirts. There is 4 Allen screws, one for each cylinder, that can be removed.
The purpose is to spray oil on the underside of the pistons cooling them.
If you have a high horse power conversion or live in hot climate this can be
a good thing. Note that if you install oil squirts you may have to install
a slightly bigger oil cooler.

Good Luck
 
Is he suggesting to drill a hole in the small end of the connecting rod for oil to get into the bushing? I know some automotive engines have a hole there, but there are thousands of Lycoming engines flying around without it, and they don’t seem to fall out of the sky from not having a hole there. I wouldn’t do that.. just put it back together and fly it.
 
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Is your "colleague" a Lycoming representative? If not, I don't think I would drill the hole.
 
Is he suggesting to drill a hole in the small end of the connecting rod for oil to get into the bushing? I know some automotive engines have a hole there, but there are thousands of Lycoming engines flying around without it, and they don’t seem to fall out of the sky from not having a hole there. I wouldn’t do that.. just put it back together and fly it.

X about 5 if I was making decision
 
This what the oil hole on the automotive connecting rod looks like. I don't know anything about the oil lubrication design but just want to show everyone what your friend wants to do. If your friends engine has high CHT on cylinders 3&4, has he investigated the baffling material, try the DanH #3 cylinder mod? Maybe doing something less drastic first before doing major surgery.

Best of good luck.
 

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Lycoming IO-320

There is plenty of lubrication for connecting rods on these lycoming engines. If you had a plugged oil gallery or something, you may have some issues. However, under normal operation, everything should be fine. Lycoming's have more camshaft issues than crankshaft issues.
Unfortunately, the only way to really tell is there is an issue with your rod journal would be to pull the rods. You can reuse the bearings, but it is advised to replace the con rod bolts and nuts with new during reassembly.
The case does have piston cooling plugs in them and they can be purchased for about 60 US dollars each. But those tiny plugs can be real bear to pull out and if you damage one and cannot get it out, then you have the chance you'd need to split the case and send it out for repair.
Unless you are doing extreme aerobatics, cooling nozzles in RV's is not really required. If you are not racing your RV and using full power for long periods of time, cooling nozzles are not really needed.
 
My colleage is worried about the aspect of connecting rod in two rear cylinders (3 and 4). He consider that is not enough lubrication at this point and is proposing me to make a hole in the top (1 or 2 mm) to let the oil fluid there. As I don't understand a lot about and I'm affraid to "touch" this important component of the engine, I would like to know if the gurus of Lycoming can give me their oppinions about. The engine is Lycoming O-320-D1A with 300 hours aprox.
In one of the picture I marked with an arrow the point in which he wants to drill the hole.

https://flic.kr/p/2mX1ogC
https://flic.kr/p/2mWZPmY

Your comments will be very appreciated. Thank you.

You are correct to be afraid. Unless your friend is has experience rebuilding Lycomings and can reference a specific Lycoming Service Instruction (SI). Then do not modify the rods. My guess is that even if a SI existed it would be a different Lycoming part, not something conducted in the field

My guess is there's some evidence he's seeing of #3 and #4 being hotter than #1 and #2...well that would be normal and not from lack of oil
 
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My colleage is worried about the aspect of connecting rod in two rear cylinders (3 and 4). He consider that is not enough lubrication at this point and is proposing me to make a hole in the top (1 or 2 mm) to let the oil fluid there. As I don't understand a lot about and I'm affraid to "touch" this important component of the engine, I would like to know if the gurus of Lycoming can give me their oppinions about. The engine is Lycoming O-320-D1A with 300 hours aprox.
In one of the picture I marked with an arrow the point in which he wants to drill the hole.

https://flic.kr/p/2mX1ogC
https://flic.kr/p/2mWZPmY

Your comments will be very appreciated. Thank you.


You have every right to be concerned.

A partnership can be challenging.

I would not experiment with a proven design.

You can always contact a Lycoming engine rep that might be a better source.

Good luck.
 
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