Originally Posted By: Imp4
Originally Posted By: emmett442
I disagree with this. If this was true, boxer engines would be blowing smoke everywhere.
Not necessarily so.
Have you taken the oil sump configuration into consideration in your comments?
Typically an automotive boxer engine configuration will have a much lower sump and comparitive oil level from cylinder centerline versus OPE plus the addition of pressurized lubrication working in it's favor.
A splash lubed OPE application is much more likely to emit a puff of smoke due to the relative level of the oil sump and the likelihood of oil pooling in the cylinder bore at shutdown.
Now I don't necessarily agree that most horizontal piston OPE will smoke at start-up, but it certainly is more likely.
On top of that, the customer base is more willing to tolerate the puff coming from a lawnmower and not complain to the OEM whereas in an automotive application customers are very sensitive to this kind of performance and will not tolerate it.
No, I didn't talk about sump level because the claim is that it's a function of horizontal cylinder orientation.
Lawn mower or boxer, the sump oil level is well below cylinder level. I don't follow how that contributes to the "likelyhood" oil making it's way topside of the piston and into the combustion chamber.
Do you store your lawnmower on-end, allowing the sump to fill the cylinder and eventually seep passed the rings?
Somehow, my splash lubed vertical shaft engines have NEVER smoked or used any measureable amounts oil! My vertical shaft mower was $1200 new, and I'd be pretty upset if it inherently smoked and used oil. Automotive vs small engine has little to do with it, in that respect.