Cylinder Head Breather Pipe

[M.J.S]

Hello folks. Hope you can help, this is still very new to me.

Whilst fitting a pair of new Dellorto carbs, I have noticed that the breather pipe from the back of the cylinder head is simply a rubber pipe pushed into the head through a rubber grommet.

This seems a very crude way of doing things. Is it right or is something missing or modified?

Many thanks.

Mark.

[ppnelan]

This seems a very crude way of doing things.

I think you mean it is a cheap & light design, i.e. typical Lotus...

Yes, that's original. I think the breather pipe between airbox & head should be a steel one with a gauze inside, but the grommet fitting in the head is normal.

Matthew

[M.J.S]

Of course. If you consult your 'Lancashire' dictionary you will see 'crude' means simple, light and Lotus like!

My car is on K&N's so the original airbox and plumbing is long gone before I bought it. All it has now is a flexible rubber breather hose shoved in the grommet and then shoved though a hole in the backplate of one of the K&N's; no sign of any steel pipe.

Do you think this will be okay or should I get a steel pipe made up? Anyone else just using a rubber hose as a breather?

Thanks.

[rgh0]

As long as inside diameter of tube around half an inch as per original pipe and it does not leak then should be OK.

I suspect if rubber pipe pushed into orginal Lotus rubber fitting in head then its ID will be a little small - OK if engine in top condition with minimal blowby but will result in over pressure of sump with enthusiastic driving and / or worn engine.

cheers
Rohan

[Allison]

This topic seems to come round every few months! The purpose of the breather is to allow excess gas to escape so whether the pipe is rubber or steel or anything else makes no odds - although one that melted could be a bad idea!

The main question is where should the pipe vent to? I raised this question at the start of the year because I was getting a nasty oil/water gunge in the air intake where the warm oil-laden gas met the fresh cold air. In early Elans the pipe vented to ground via a right angle grommet and a pipe leading down past the gearbox. In later cars to reduce emissions it was routed direct to the airbox.

Mine now vents to ground, airbox is cleaner and there's nothing noticeable on the ground.

Peter

[chrishewett]

I just fitted one of cliveyboys mod breathers. Hopefully that will now stop the plugs getting sh**ed up! It's got to be worth a try.
Chris

[M.J.S]

This topic seems to come round every few months! The purpose of the breather is to allow excess gas to escape so whether the pipe is rubber or steel or anything else makes no odds - although one that melted could be a bad idea!

The main question is where should the pipe vent to? I raised this question at the start of the year because I was getting a nasty oil/water gunge in the air intake where the warm oil-laden gas met the fresh cold air. In early Elans the pipe vented to ground via a right angle grommet and a pipe leading down past the gearbox. In later cars to reduce emissions it was routed direct to the airbox.

Mine now vents to ground, airbox is cleaner and there's nothing noticeable on the ground.

Peter

Hi Peter.

I like the idea of running the pipe straight to the underneath and venting well away. Somehow the idea of venting a warm oil/air mixture back through the carbs doesn't sound too healthy for surely most of the venting will be drawn into the carb barrel nearest the pipe. That surely must cause an imbalance of some degree.

My other toy is a race tuned '67 Mini Cooper S and with the Mini's all three vents; crankcase, rocker cover and endcover, are all vented out through the inner wings and NEVER vented back through an airbox; at least not on tuned cars.

Mark.

[pamitchell]

There is a good discussion on this under ELans forum, April 11,08.
"Oil Breather Question"
Phil

[M.J.S]

Thanks Phil, I'll look that one up.

Mark.