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| Lubrication on two cycle engines |
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eric524
New member
Username: eric524
Post Number: 3
Registered: 02-2017
| | Posted on Wednesday, February 22, 2017 - 05:24 pm: | 
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Many thanks to JB for the good advice on rings. I wonder if I might impose further for some tips about lubrication. Since there are no oilers on this engine (see photo on "Piston Ring Problem" thread) am I right in assuming that this engine gets its oil through the gas? Stan Grayson and others suggest about a pint per 5 gallons. Is that still about right? But this engine has separate sumps for each cylinder. Does this mean it is also lubricated by oil from the crankcase? And what is the function of that pipe (about 3/8") that goes in an indentation in the conrod from the wrist pin to the crank journal? And what do the little pipe nubs (about 1/2" long and cut off at an angle) on the bottom side of the journal do? By the way, all this piping leads to the heart of the bearing through drilled holes. And if I am right about oil in the sump, how much? About one quart in the sump covers the bearing about half way up. |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1282
Registered: 07-2002
| | Posted on Wednesday, February 22, 2017 - 09:30 pm: |
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Two cycles running on mixed gas accumulate oil-gas mix in the sump. You could put a couple of tablespoons of oil to help with early lube, more than this will be drawn into the cylinder and drown the motor. The tube from the wrist pin to the rod usually delivers oil collected at the wrist pin from a drip oiler on the cylinder, the oil is captured between the rings and makes it's way to the wrist pin. If there are no plugs on the cylinder for an oiler, I would guess they did the reverse and used the rod oil to oil the wrist pin. |
eric524
Member
Username: eric524
Post Number: 4
Registered: 02-2017
| | Posted on Thursday, February 23, 2017 - 11:04 am: |
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Many thanks again, JB. You've shed more light on my ignorance. Clearly, I have been led astray by the typical car engine, and by the lubrication of the Yanmar diesel in my boat. But obviously we have different principles at work here. I thought, mistakenly, that the big 1" plugs on the lower sides of the blocks must be for the addition (and extraction) of oil from the sump. And then, similarly, there are the smaller plugs on the faces of the inspection plates. So, when you say that a lot of oil in the sump would get drawn into the cylinder and drown the engine, would it be drawn up through the bypass? I am still puzzled, though, about the function of those little pipe nubs sticking out from the bottom of the journal. I also found that thread from back in 2007 on oil/fuel mixture in the sump to be helpful. |
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