23 Jun Catching Flak
That’s one more item we can check off the 318’s fabrication list.
Fabrication just finished making a quick and easy catch can for the 318i turbo build. For those not in the know, an oil catch can aids the PCV (positive crankcase ventilation) system. Normally, oil vapor and blow-by gases (gas that blows through the combustion chamber, past the piston rings and into the crankcase) are routed through the PCV system, out of the crankcase and back into the combustion chamber, where they are used in combustion and removed as exhaust. Over time, the oil vapors can thicken along the walls of the PCV system, creating a gunk that will necessitate a thorough cleaning of the system. This is where the catch can comes in. The catch can is placed inbetween the crankcase and the intake in the PCV system. It’s built such that the oil vapor will travel through some steel wool (or other material) inside the catch can, and that gunk will be caught by the catch can, collecting there until the driver empties the catch can of all the nasty buildup inside. The resulting vapors can then either be sent to the intake system, or vented into the atmosphere. Draining a catch can is an easy technique (so long as the catch can is easily removable), and is usually done at the same time as an oil change. We made the design on this one pretty simple, as there is already a LOT going on in the 318’s engine bay.
The filter we’re using to vent the vapors to the atmosphere is pretty interesting. It’s about half the size of a thimble, and screws into anything you can put a normal bolt into. The construction of the filter itself looks as if its made of a million tiny solid beads, but it manages to push out a good amount of air. Quite the interesting little doozy, we must say.
Finding a place for it was a little trickier. There’s plenty of space in the passenger side of the engine bay, but there’s already so many components over there that it started to look a little cluttered. Therefore, we found a perfect spot for the catch can itself (right behind the intake manifold) and the mount to hold it in place (coming off the bolt on the dipstick mount). Once we polish the intake manifold to match the catch can and charge piping, it’s going to look pretty slick.
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