A while ago I fitted a home-made system from the block (where the old PCV valve was fitted to the x-flow) to a home-made catch tank. This was to replace the old manifold connection that was there before I fitted bike carbs. I've been think that it's not an ideal setup because:

(a) The tank used to be a bike water bottle designed to keep liquids cool - so the hot oil fumes stay hot and just go straight through, and
(b) A load of vapour comes out of the rocker cover filler cap vent and fouls up the top of the engine - so I need to fit a cap to divert them to the catch tank.

Now I have no idea about where a catch tank needs to be fitted - can it be low down, or does it need to be up high?

I plan to have 2 pipes, from the crankcase and the oil filler cap. I'm not bothered about fitting a return to the sump - I'm content to drain off the excess now and again.

My other problem is where to fit the tank - I'm a bit short of space under the bonnet these days!

I just have a small cheap ebay breather filter venting the catch tank to stop any fumes escaping (or spiders creeping in) so long as you vent to atmosphere this is sufficient (i.e. though filter or open pipe). Older engines I believe used to just vent via a pipe onto the road!

Not sure it matters where you put the tank, it's only there to catch escaping oil after all, mine is plumb via a long piece of 19mm hose I happened to have, a lot of the oil will simply run back down into the engine..

The only thing I get in the tank seems to be water, as you might expect from blow buy gasses, no oil at all!

Nothing to stop you running more than one hose to the catch tank, i.e. rocker cover and crank case.

Dan

[Edited on 21/4/11 by Bluemoon]

[Edited on 21/4/11 by Bluemoon]

ive squeesed a little Obp tank on the bulkhead below the batery. Just need to pipe it up.

Daft idea maybe. 2CVs use a sealed filler cap and a one-way breather that causes negative crankcase pressure. When the valves fail they pee oil out. Many of the 2CV kits use after marke 'foo-foo' valves (because they make that noise?). They work by pumping pressures in the crankcase and don't need to be sucked by manifold pressure (unlike the PCV?)
Maybe you could adapt one for the xflow, but you would need a sealed filler to make it work. Then your breather pipe could go anywhere where there's room for your catch tank

I was looking for something more conventional - I just need a small catch tank with 2 inlets, and a drain plug.

The main question is - can it be mounted low (bottom of block) or does it have to be as high as the rocker cover?

hi david, i have the the set-up off, one from the rocker cover, and one from the block, and i have mounted mine low down it also has a filter and a drain plug on it, and seems to work ok.

stu

I had mine low down until it decided it wanted to be part of the oil system and rapidly filled up! its now next to the battery and not had any problem, as for the vent I run a tube from the vent on the catch tank down the middle of the car and out by the diff, I found that venting with a filter in the engine bay meant it could get quite 'fumey' in the car.