How to vent with watersheds?

[mjmoran]

I have had a gas vapor problem ever since I have installed the watershed K&Ns on my 68. There is no smell in the engine compartment or in the cabin when the windows are up...once a window is cracked the vapor becomes more and more evident. I am sure now that the cuprit is improper venting in the engine compartment, as there was no problem before the mod. Any pictures/diagrams/ etc that could help me properly rout all the hoses and get enough venting?

Right now the crankcase vent hose goes from the crankcase breather port on top of the block to the RHS wall. Then there are two other hoses (the in and out ports for the oil tank vent) that were vented to a small bottle with a K&N filter on top. These were joined by a "tee" connector so they would both go into this bottle. My guess is they all have to go to an inlet on the watershed housing...but bring it on.

thanks

[911pcars]

I posted this engine compartment pic in a thread on vintage air fliter housings, but the same setup would apply to the K&N housings. I'm unsure about your description of the crankcase breather hose going to the RHS wallb but it continues past this into the oil tank.

A proper catch can should be installed between the filler neck breather hose and the carbs. In the case of individual carb filter housings, the catch can should have three ports; one intake from the filler neck (oil/gas fumes IN) and two ports OUT, one to each filter housing. There are nice, spun aluminum, welded tanks in the aftermarket. Mine is a used WW reservoir tank sourced from a wrecking yard (car unknown). It's translucent to see what's inside.

The K&Ns have an opening on the side of the top cover to attach a grommet and hose. On vintage Filtron units, I created a hole on top of each housing, then installed some PCV grommets and heater hose on both ends (filter housing and catch can). There are probably more elegant solutions.

The small K&N filter on your catch can could allow unburned fuel (and fumes) to escape into the engine compartment. From there, fumes can go through the engine air shroud and eventually through the heat exchangers to the interior. My guess.

I know you said '68, but by any chance MFI?

Sherwood