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crank case breather into exhaust

fehdxl

Well Known Member
I’ve seen the breather tube end next to the exhaust, but never piped into the exhaust. Yes, the blue hose is attached to an modified exhaust nipple. Why would someone do this? Sure seems like a good way to cause crankcase pressurization issues. Thoughts?
 

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Vacuum Valve

I switched to the anti-splat set up about 100 hours ago and have been very happy with it. I didn’t use their saddle mount fitting as I had a threaded bung welded into the colector of my 4 into 1 system already. The vacuum valve is the key. We used them in the drag racing world but called them gulp valves with the theory being running a crankcase vacuum would reduce the pressure against the bottom of the pistons allowing for higher RPM. It does seem to help with the small oil seeps as well.
 
There are several threads and tons of posts. Look for the schematic and photos posted by DanH on this subject. They will always plug so require periodic servicing. Oil does not last forever either. Dan utilized and second check valve off a tee to act as a pressure relief in case it does plug. Quite safe and keeps oil off the fuse for ever.

I have a system on the shelf and have to get off my butt and get it installed. I have my doubts about the measurable hp claims, but there are solid physics (ok, fluid) supporting lower windage losses inside the crankcase. The less oil kept whipping around in there is much more friction than just air alone.

Try this link https://www.danhorton.net/Articles/Separator-or-Condenser.pdf

This should give you a good scope of the crankcase ventilation options.
 
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I have the ASI crankcase vacuum/breather setup, which incorporates a T’d off check valve to prevent crankcase pressurization, and I’ve been quite happy with it. There is no oil on the belly and any oil seepage seems to have stopped. On mine, the vent tube going into the exhaust pipe is about 18” from the end of the tailpipe, and I can shine a flashlight up into it to check for coking on the tube. I can also easily remove it when the cowl is off for inspection. My breather line goes directly to the check valve T and exhaust pipe tube assembly - no air oil separator required.
 
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