Thx was intending to post a pic with but apparently this phone doesn't like the idea as that option is greyed out .lol. I'll try with the other halves phone when I get a hold of it.
I have read the posts I could find on the subject. I just never saw anything positively identifying where the vent was I'll look at it when I get home, put it in a can and fire it up. If it is a vent I'll tie it in to the current crank vent system and see if that cures my leak . I'll let you know after I've completed it or found it wasn't a vent. Thx
You dont want a vent in the crankcase. The breather system on the 117's is designed to keep a vacuum in the engine. A crankcase vent will just cause a vacuum leak. There should be a check valve in the rear breather to let any positive pressure out of the engine, but does not allow air to be pulled into the engine through the rear breather. Big dog claims that this system stops oil mist in the crankcase and provides a better piston ring to cylinder wall seal. I don't know this for sure, but you would think it would boost hp slightly because it reduces drag on the engine. There is no air in the crankcase that the pistons have to push and pull in and out of the breathers.
I'm guessing the primary is closed off from the engine. There is a seal I assume on the left side of the engine. Can't keep loosing one side and filling up the other, right? Doubt if it buckles at the engine case due to breathing. I could see heat expansion and a lost quad-ring at the case.. if harley style... to primary... and guessing here, but no [rubber] memory to follow the expansion. Brittle/hard/quad? And then again, we wipe the bottom clean and leak is a drip straight down? And remember, that's air pushing that drip back so we are saying right under the stator area, or derby cover area?
I see pressure on top of the piston and under the piston. Follow the air in the chamber. This becomes compressed. The comp side, the air is pushing the ring out, and the ring's air gap(s) is that gap of air going down into the crankcase. And let's stop action, meaning, the crankcase right now is at 14.7psi or 1 atmosphere. That means air volume is set. no more air in or out, it's just at 0. Where is the vacuum? The next move, meaning, keep the air in the crankcase as no more air to enter, but look at the ring gap and that speed of that little pressure past the rings... has added more air into what is already displaced... where is the vacuum?
C/C is more like a balanced P & V under the pistons, but one goes up the other comes down. Add chamber fulling and here is where open atmosphere at the vent tube goes back to 1atmo is to balance that escaped volume above is now added below. Where is what leak?
Said oil pressure is where? Said mist is a constant as is the oil pump. Said crank throws, rod blades mixing it up. The cup sweeper, or breather guillotine closing off and collecting the gulp of oil out of the rods. Where does the mist stop/slowdown. Compression and scraper are still going to wipe it clean even old style engine families, begins with h, ends with n.
Drag is swinging crank mass thru oil is the drag. Eliminate it thru vacuum, sure. Where is the equal pressure under both pistons so they move and not be stopped by a closed bubble and bounceseabouncesee?
The breather system isn't really a "breather" system per se. It's a vacuum system. The front breather line is hooked to the manifold. The rear breather has a one-way check valve. This puts a vacuum in the engine. If you unhook the rear breather from the check valve, there will be a vacuum in the hose.
