Oil Catch Tanks

[moggymaniac]

Are they worth it? On removal of my manifolds, the colour of fuel sitting in the ports is a mirky mix of fuel and oil colour. I can only guess that the timing chain cover to carburettor vent pipe connection is causing this. I've thought about putting a catch tank in line as surely this can't be good for horsepower with oil in the fuel, but thought i'd ask of your experiences first!
Cheers, J

[ianmack]

I don’t think small amounts of oil will do any harm, indeed people used to add Redex upper cylinder lubricant to their petrol for its supposed benefits. Unless of course your engine is using large amounts of oil in which case it will need more than a catch tank.

[philthehill]

Having a catch tank in line will be no good as the oil will be in the form of a vapour and therefore will pass straight through the catch tank to the carb as it appears to be doing currently.
From your description you appear to have the timing chain cover with oil separator.
The oil separator should do as it says and stop the oil getting past it which then drains back into the timing chain cover and ultimately the sump.
If the oil separator is not doing its job it could be that the gauze has disintegrated (a common fault) or your engine is breathing badly.
How much oil is it using i.e. how many miles per ltr ?
The gauze can be cleaned out and the mild steel gauze (which is the same as pan scrubs) replaced with stainless steel pan scrubs.
Below is the usual mess to be found in a timing chain oil separator
I do have a catch tank on my Minor but that is a specific motor sport requirement. The engine breaths through two engine oil separators, one located on the timing chain cover and the other fitted to the fuel pump aperture.
The catch tank is fitted with a sight glass so that the amount of oil contained in it can be determined.
As very little oil gets past the oil separators they are doing their job.