Case breather

[onex28]

Thanks Jake, I have a Onex and the rocker covers are external to the cowl. Is there somewhere else on the engine to route the out line?

[tljones42]

I am building a Onex with the turbo engine which has an oil sump. I ran the return to the right side of the sump versus outside the cowl to the valve cover. Haven't run the engine yet but couldn't think of a reason this will not work since the Sonex case breather I'm using dumps back into the sump on the left side.
Tom Jones

[kmacht]

I used rubber hydraulic hose for my breather line. A piece of 1/2" copper pipe goes tightly into the breather plate and works great to clamp the rubber hydraulic hose on to. I built a seperator and returned it to the valve cover. I originally had it just dumping out down by the gear leg but that turned out to be a low pressure zone and was actually sucking oil out. I never liked the idea of running the return to the sump plate. If that hose ever leaked you could dump all the oil in your engine overboard pretty quick and not even know it was happening.

Keith
#554

[Bryan Cotton]

Adam and I have been defeated by the breather fabrication. He tried it first and I went second. We filled our tube with sand for bending. I am going to fabricate my own breather plate and tap it for an AN nipple. We also have a top mount oil cooler.

On Morry Hummel's half VWs, he uses a check valve on his breather. Lets air out but not back in. Anybody ever try this on a full VW? Could help in the quest for the elusive dry VW.

[radfordc]

On Morry Hummel's half VWs, he uses a check valve on his breather. Lets air out but not back in. Anybody ever try this on a full VW? Could help in the quest for the elusive dry VW.

Probably no effect on a full case VW. A 1/2 VW pumps a liter of air in and out on each rotation. On a full case engine, since the pistons move in opposite directions, it doesn't pump any air at all.

[Rynoth]

Adam and I have been defeated by the breather fabrication. He tried it first and I went second. We filled our tube with sand for bending. I am going to fabricate my own breather plate and tap it for an AN nipple.

Did you anneal the aluminum tube? Mine was seemingly impossible to bend before giving it a good torching, then it wasn't too bad. Not worried about structural strength, but the ID of the tube may be important to keep in spec.

Also, I ended up ignoring the pre-punched breather hole in the baffles. I riveted an aluminum patch over that one and just made a new hole where my successfully bent tube ended up pointing. The hardest part for me was finding appropriately sized oil-complaint hose. Coolant hose is cheap and readily available in this size but not good for oil, finally found 5/8" marine fuel hose on Ebay. This one hose probably weighs more than all of my fuel and oil lines combined.

[Bryan Cotton]

Probably no effect on a full case VW. A 1/2 VW pumps a liter of air in and out on each rotation. On a full case engine, since the pistons move in opposite directions, it doesn't pump any air at all.

True, but there is a lot of flow front to back and front again. I assume this is why we need a breather in the first place, and I suspect a check valve would still have the case operating with a slight vacuum.

Thanks Ryan for the pic. Does your breather go up at all? Hard to tell. That was one of the things that was challenging for us.

[Rynoth]

Probably no effect on a full case VW. A 1/2 VW pumps a liter of air in and out on each rotation. On a full case engine, since the pistons move in opposite directions, it doesn't pump any air at all.

Thanks Ryan for the pic. Does your breather go up at all? Hard to tell. That was one of the things that was challenging for us.

No I don't think it goes up any, just 2 shallow bends to clear the oil cooler then point generally towards the firewall. Everything got easier when I stopped expecting to hit the pre-punched hole and just aimed for the general area that was clear of intakes/accessory plate on the backside of the baffles, then let the more-flexible hose take it from there. I'm not sure how much the non-turbo intake manifold differs from the turbo or what things look like on the backside of your baffles in that area, I had a lot of room to work with if i could just get around the oil cooler with the tube.

[Onex107]

I had a heck of a time making the " S " bends without kinking the tube, so, I rotated the fitting 90 degrees towards the right side and made a large curving bend around the oil cooler to the right side fire wall. As per Mike Bush, I don't return any oil to the engine. I catch it in a home made filter jar and measure the blow by at each oil change. That plus oil added is a good indicator of what's going on in the engine. I'm getting eight to ten ounces in 25 hours and adding back about six. I presume the difference is burned. 260 hours and counting.
Onex 107