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MG Midget and Sprite Technical - Weber breather

I have a Weber setup on my midget.
Theprev owner made a catch tank for the breather (see pic, yellow oil bottle front right)
I wonder if there is a better way of doing this
Please advise


Mallorcaben

I use another windscreen washer water bottle & holder.
Brad (Sprite IV 1380)

You can either buy a catch tank or have one made. I had one made and it wasn't that much more expensive that buying something off the shelf.


Daniel Thirteen-Twelve

Please excuse my ignorance but this catch tank for a DCOE is a new one for me - what is its purpose and where does it 'drain' from?

Thanks in anticipation

John Turner
John Turner (Midget & MGB)

The catch tank captures breathed 'gas' from the engine. On a car with SUs the breather pipe from the crankcase via the front timing cover feeds back into the induction system. On a car with a Weber DCOE there is no provision to be able to do this so the choice is to vent to atmosphere (not legal for most UK motorsport) or vent to a catch tank. Mallorcaben's car also has a breather from the rocker cover venting to his improvised catch tank.
Daniel Thirteen-Twelve

IIRC cars fitted with fixed choke carbs such as DCOE, DHLA, and various others as standard had the crankcase breather fed into the carb side of the air filter assembly so the pressure difference between atmospheric and that inside the air filter drew the crankcase vapours in to be mixed with the combustion mixture. This worked fine IIRC with standard paper filters but higher efficiency filters such as K&N had less pressure drop so the system didn't work as well.
David Billington

Car Builder Solutions do them at resonable prices. If you have lots of money Mocal do a nice one at about £60. It's easy to make one out of a plastic or aluminium contanwer. A lot of climbing accessory shops sell nice aluminium drinking bottles in various colours. Clear plastic is best, as you can easily see what's in there. The expensive alloy ones have a drain plug and a sight tube on the side.
Cheers John
JOHN HALL & JULIE ROBERTS

John,

Daniel will likely confirm if still the case but when I held a RAC MSA license the requirement IIRC was for all catch tanks to have a visible indication of content. That meant that milk containers or washer bottles were ideal and cheap, metal containers needed some form of sight glass. That of course doesn't matter if you're just using it on the road and doesn't need to meet their regs for speed events/racing.
David Billington

Ah,

All is clear!

John Turner
John Turner (Midget & MGB)

Car Builder Solutions sell catch tanks described as suitable for motorsport but that are the WRONG SIZE for use in motorsport.

Yes, sight gauge for motorsport though I once came across a catch tank that had a little dip stick which while not complying with the letter of the blue book certainly met the spirit of the intention of the regulations.
Daniel Thirteen-Twelve

mallorcaben, What's that on the valve cover? A hole? Isn't there usually a tube on that to a vacuum source or otherwise piped into the crankcase vent setup?
See picture.


J Van Dyke

J Van Dyke, its an allen screw that blocks a hole. The reason I don't know.
By the way anyone, the piping from the crankcase is deteriorating due to manifold heat. I need some kind of heat resistant pipe. Anyone actually know the diameter of the pipe so I can order more?
Mallorcaben

Not sure of the diameter but I have used some old oil cooler pipe which is both heat resistant and the perfect diameter. HTH
D Prince

This thread was discussed between 12/04/2009 and 23/04/2009

MG Midget and Sprite Technical index

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