MEP 831A Oil Filling Procedure

[Chainbreaker]

I don't own an 831 but find this starting aid oil hole intriguing. My "guess" would be that the hole shown in the photo posted by "Dav5" in post # 18 above is positioned on the intake side of the intake valve? So, I wonder if the idea of adding the 2cc of oil was supposed to help by allowing a small amount of oil to enter cylinder and flow down to piston/rings to help raise compression when cold? Or, was it an aid to prevent potential cylinder scuffing with added lubrication and less resistance when extremely cold...or both?

 

[dav5]

We never used the start assist on this engine.
Any early engine that had the assist plug in the cover was cut off and glued into the cover.
The yellow cap is only for oil fill.


Servicing the engine proved to be very difficult and messy using the oil dip stick for the GI's in the field.
So we had Yanmar add the cap in the top cover

I have my second unit at my camp in northern Ontario, Canada. I started it up a few times this winter at around 0 degrees F and it started immediately. I can see why you glued in the plug.

 

[Kenny0]

I don't own an 831 but find this starting aid oil hole intriguing. My "guess" would be that the hole shown in the photo posted by "Dav5" in post # 18 above is positioned on the intake side of the intake valve? So, I wonder if the idea of adding the 2cc of oil was supposed to help by allowing a small amount of oil to enter cylinder and flow down to piston/rings to help raise compression when cold? Or, was it an aid to prevent potential cylinder scuffing with added lubrication and less resistance when extremely cold...or both?

I would say it does 2 things 1. Seals the top compression ring 2. Slightly raises the compression ratio. That would raise the temperature of the air when compressed. On a diesel, the hot air of compression ignites the fuel. Too much oil can cause hydostatic lock which is bad. In this case a little is good more is not better.

 

[robson1015]

My mep-531 has the starting oil hole, it is a very small hole unlike the oil (yellow) fill hole on the mep-831.

Sorry - couldn't find a pic of the mep-531

 

[selkirkcraig]

Just wanted to update. Based on all the information posted on this thread, I filled one of my MEP 831A with oil after removing the Yellow cap on top of the valve cover on the top of the engine. I watched carefully through the dipstick opening as the oil filled the base of the crankcase until the dipstick indicated full. Went ahead with start up procedure as per manual, and unit started up immediately without any issues. I will follow the same procedure in the morning on the second unit, and hope for the same results.