Oil breather question

[tyasman]

The oil filler cap on my 1970 S4 is not drilled. Is this correct? Or is there a breather pipe somewhere else on the engine. If not, it may explain why I'm getting signs of oil beside the dipstick. If it should be drilled, what size hole?Thanks for any comments

[oldelanman]

There should be a breather pipe running from the rear RHS of the cylinder head to the carb air box. The filler cap is sealed.

[Allison]

Hi,

we had a discussion on this subject some months ago (I started it!). Yes there should be a breather and it runs from the rear of the cylinder head by the carbs. Question - where should it go to?
I had mine linked to the air intake box and the result was an nasty oil/water goo which sat in the air box and oozed out onto the bulkhead - altogether an unpleasant experience! I believe this was done for emission control purposes.
The alternative is to pipe it down through a right-angled grommet (or similar) to somewhere below the gear box where the sludge can ooze out onto the road. The S3 cars had this pipe as standard and it was secured by the engine/bellhousing bolt at the top of the block and by a small bolt in a specially drilled hole on the "fin" of the gearbox. The grommets are I believe unobtainable so I have an ordinary grommet in the head and a right angled copper elbow (from a plumbing supplier) linked to the pipe.
Now the airbox is clean, there is no sludge on the bulkhead....problem solved!
Peter

[oldelanman]

Lots of oil from the breather can be an indication of worn rings and/or bores which allows excessive piston blow-by and consequent high sump pressure.

If you want to do away with the closed circuit breather system and stay "green" you should really include a catch tank to avoid discharging oil onto the road. - or am I being too P C ?

Regards,

[spanner]

http://www.aircraftspruce.com/menus/ep/ ... ators.html

[pamitchell]

I decided to remove the original breather tube set up with a plumbing pipe bushing running into a small K&N breather filter. The rear hole is just right for 1/2" pipe bushing with a 1/'4 threaded center. I used a 1/4" brass elbow and pipe that connects to a 1/2 "heater hose and the K&N. The tap size is 1/2-14 NPT. Coat the tap w. bearing grease and and stuff the breather cavity with a rag w. grease to catch the metal shavings. Use pipe thread sealant on all the threads.

Phil

[cliveyboy]

Tyasman
Firstly you will tend to get a small bit of oil coming out the dipstick a trick myself and a few others use is a boot from a spark plug lead. It holds the dipstick firmly helping stop it rotating around and seals it as well.
Depending what engine you have can cause a big difference in breather problems. If you have the tall block conversion (1700cc) from later fords etc more oil will come out of the engine breather at the back.
On my Sprint I made a custom engine breather to replace the original block to airbox pipe. It is a tee piece the same length as the original but blanked off at the end so it vents down the extra leg. This means it fits the same as the original so you do not have to seal off the hole in the airbox. (there is a picture on my website)
A length of rubber tubing from the tee piece vents down under the car or to a catch tank.
Not venting back into the airbox keeps the plugs much cleaner.

If you have the original tube on the car take it off and clean it. Inside the tube is a fine mesh filter which if gunged up ( and it probably is) will give you back pressure that can force oil out the dipstick).

Clive

[steveww]

I am using a Pipercross breather filter on my S4. 13mm plumbing pipe works well as already mentioned as a means to connect everything up.

[elancoupe]

If you want to do away with the closed circuit breather system and stay "green" you should really include a catch tank to avoid discharging oil onto the road. - or am I being too P C ?

Regards,

+1

I run a breather om the front of my cam cover, too. It and the airbox breather are connected to a catch bottle.