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Crankcase Breather Tube "picolo" vent Hole

T

Tcheairs

Well Known Member
Without me having to remove my lower cowling to find out, does anyone know how far up into the crankcase breather tube (Continental XIO 360 engine) the (ice, picolo little vent hole) is located. I'm setting up my crankcase dehumidifier unit with an input hose.
 
Depends on where you or your builder drilled it when it was installed. If it is a vans breather there is no whistle slot in it from the factory. I had to drill my own.
 
Design plan is for the breather tube to be INSIDE the lower cowl? The breather tube on my RV7A protrudes about 5 inches below the cowl. I assume this is to deposit the blow by on the belly rather than inside the cowl. I'll just run a boroscope up in there and see what I can see.

Thanks
 
Tcheairs said:
Design plan is for the breather tube to be INSIDE the lower cowl? The breather tube on my RV7A protrudes about 5 inches below the cowl. I assume this is to deposit the blow by on the belly rather than inside the cowl. I'll just run a boroscope up in there and see what I can see.

Thanks
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The cowl drops below the fuselage belly, with the outlet facing aft.
The vent tube outflow follows the aft flowing outflow of the cowl even though it is inside.
Since it is inside, it is never exposed to below freezing exterior air ( if installed per plans).
 
Vent

I thought the plans show it terminated just above the exhaust pipe so byproducts burn off.
I drilled a hole about 3" above the end. Insert a rod into the hole and bend the hole by swinging the rod upward. The hole will be shaped so any drips stay inside the pipe.
 
Last edited:
wirejock said:
I thought the plans show it terminated just above the exhaust pipe so byproducts burn off.
I drilled a hole about 3" above the end. Insert a rod into the hole and bend the hole by swinging the rod upward. The hole will be shaped so any drips stay inside the pipe.
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Exactly the way I did it. I don’t care if it is right above the exhaust I still did the whistle just in case there is ever an obstruction. I doubt that will ever happen though.
 
I will say that the whistle slot is important. I had the breather tube on our Cherokee freeze up on a very cold day in Wisconsin. Things were fine until we landed. During taxi back to the hangar, when the RPMs were lower, it apparently froze up. When I powered up to resume taxiing after a short stop, the front seal popped out, spewing oil all over the cowling. Glad it happened on the ground.
 
robertahegy said:
I will say that the whistle slot is important. I had the breather tube on our Cherokee freeze up on a very cold day in Wisconsin. Things were fine until we landed. During taxi back to the hangar, when the RPMs were lower, it apparently froze up. When I powered up to resume taxiing after a short stop, the front seal popped out, spewing oil all over the cowling. Glad it happened on the ground.
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Don’t the crank case vent tubes on cherokees protrude out of the bottom of the engine cowling?
 
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