Dry sump catch tank venting

[Shaun_E]

Just got my K series car back on the road with newly fitted dry sump. The catch tank is mounted in front of the engine roughly where the Apollo tank was. My problem is that I get a pretty grim smell in the cockpit. The tank has a hose running from the top of the conning tower to a hole in the side of the tank and there are several holes drilled in the cap of the tank. I am using the standard Caterham plastic tank.

Should I block the holes in the cap and run another hose from the tank to underneath the car?

 

Yellow SL #32

[Dirty Den]

Hi Shaun -

 

I think so, something similar was done to my RoadSport A. I have two catch tanks mounted side by side in front of the scuttle - the dry dump vents into one tank, which is connected to the other with a small piece of hose at the sides. This second tank then has an exit hose which goes underneath the car.

 

In my case, each of the catch tanks have a black plastic cap with a very small vent hole in them.

 

Den

 

http://www.dens7.co.uk

[Stuart Faulds]

Den, the hose you describe as venting under the car should normally be connected to the gearbox breather.

[Dirty Den]

Hi Stuart -

 

Hmm, perhaps I've got confused

 

I'll tray and have a check tonight and see - but I'm pretty sure I do have a pipe exiting from the catch tank and going underneath the car...

 

Den

 

 

 

http://www.dens7.co.uk

[robmar]

Shaun - when I used to run th eplastic bottle I got the same situation as you, if not worse as it was mounted on the front of the driver footwell and all the fumes went straight in your face ... the problem was that the fumes came out of the hole sin the top of the cap...

 

my 2p suggestion if you want to keep this is

 

1. cover the holes up / replace with new cap

2. run a 2nd pipe back towards the gearbox/back of car for all the fumes to escape to as you suggest

 

I am not sure with the plastic bottle that you will get rid of 100% of the fumes with the above but it should be better

 

I have now got a catch tank situated on the bulkhead and have one of the breathers with a piece of tube going down near the bellhousing and back towards the gearbox, all fumes now expunged to behind me and no further problems

 

 

rob

 

[Peter Carmichael]

Den, the hose you describe as venting under the car should normally be connected to the gearbox breather

 

There should be two very distinct and separate breather/catch tank setups. If you run a catch tank on the gearbox breather, it should vent into the bottom of an expansion tank. When the gearbox cools down, you should expect all the oil to be drawn back down into the gearbox.

 

FWIW I run my vent from the DS catch tank to ground. It keeps your engine bay much cleaner.

 

The Caterham system I have seen has a two stage interconnected catch tank on the scuttle. Venting this to ground makes sense, but the gearbox breather *must* not go anywhere near it ❗

[Stuart Faulds]

Peter, thank you for your thoughts, but since Den's car is an ex-race Roadsport A, I was merely telling him how it would have been run. Venting oil (engine or gearbox) onto race tracks is not viewed as very desirable by the average scrutineer, and the normal race setup uses 2 interconnected catch-tanks to contain both gearbox and engine excesses.

[Shaun_E]

Thanks guys - will cover the holes in the cap and get another bit of tube to run underneath the car.

 

Yellow SL #32

[Peter Carmichael]

Ah, right. I'll stick to my comment that breathing combustion fumes into a gearbox is a stupid bit of non-engineering.