Achieving atmospheric crankcase pressure

[Lockgessner]

Sorry for the basic question but im new. While it makes sense (theoretically to stuff a crankcase) I don't understand the basis on this. Is it because at atmospheric pressure the crankcas is recieving the maximum possible charge? Also on another thread I was reading about a saw with an "exhuast port demple" which leads me to believe the saw was recieving air from the exhaust side in addition to the intake side (am i just extremely mis guided on this).

Thanks in advance for any insight!

Lock

 

[TIMMAAHY]

Sorry for the basic question but im new. While it makes sense (theoretically to stuff a crankcase) I don't understand the basis on this. Is it because at atmospheric pressure the crankcas is recieving the maximum possible charge? Also on another thread I was reading about a saw with an "exhuast port demple" which leads me to believe the saw was recieving air from the exhaust side in addition to the intake side (am i just extremely mis guided on this).

Thanks in advance for any insight!

Lock

I think I can help you out on one of your questions, the whole idea behind stuffing a crankcase is simple really and I think you are trying to make it more complicated than it really is. It's all about keeping the volume up. The theory behind it is that if there is alot of open space inside your crankcase then the pressure drops and when it comes time for the air/fuel charge to enter the cylinder not all of it makes it in. So by keeping the crankcase area small you are basically making it easier for the engine to get the full amount of air/fuel into the cylinder/combustion chamber. By stuffing the crankcase you are really causing the pressure to rise in the crankcase and we all know a fluid or vapor/gas will move faster if it's under pressure right?
Now as far as the dimple on the exhaust port, I am not too sure what it is you are talking about, if you can explain what it is I might be able to help you out.
Hope this helps.