41 replies to this topic

[Jack BRCG]

i want to put a breather into my rocker cover, how would i go about doing this??

[Dan]

Drill a hole, and bolt one in. And remove the rest of the breather system because it will change the way it works completely. You will have to plug the emissions inlet to the carb. You are far better off keeping the factory breather system in place on a road car though.

[Jack BRCG]

thanks il have a think. i thought i could just add one and keep the crankcase breathers on. hmmmm

[midridge2]

just go on ebay and buy a very cheap early engine rocker top with the breather pipe in.

[liirge]

thanks il have a think. i thought i could just add one and keep the crankcase breathers on. hmmmm

Can I ask why you are doing this?

[bmcecosse]

Yes - buy a rocker cover that already has the breather - I don't know WHY they evr deleted this breather. Your engine needs all the breathers it can get - and connect them all to the carb inlet pipe to remove the carcinogenic fumes which you definitely don't want to be breathing.......

Edited by bmcecosse, 11 September 2011 - 05:21 PM.

[liirge]

Yes - buy a rocker cover that already has the breather - I don't know WHY they evr deleted this breather. Your engine needs all the breathers it can get - and connect them all to the carb inlet pipe to remove the carcinogenic fumes which you definitely don't want to be breathing.......

Yes but it completely changes how the breathing system works, it was set up very differently when they had the standard breathing rocker cover, if i remember rightly, what do you think the point of the oil filler cap that has a hole in for?

[Dan]

I don't know WHY they evr deleted this breather

Because for the ventilation system to work there has to be somewhere for a controlled amount of fresh air to come into the crankcase and in order to blow out all the crud from everywhere the air has to flow through in a controlled route. The air flows in through the breather that already exists in the rocker, the one inside the filler cap where a small hole allows a metered amount of air in. The early breather systems were updated because they didn't work very well. The positive ventilation system is better by far than a basic open to atmosphere system where each part of the engine is directly vented through a filter. And if you just connect each part up to the carb without letting fresh air in somewhere, the engine will be pumping against a partial vacuum it is creating itself which won't be good at all.

[bmcecosse]

Indeed it IS good! Cuts down oil leaks and oil consumption nicely - I've run many A series like that with great success. But if you wish - leave a breather open if you like - although I would NOT have a filler cap with a hole in.

[Dan]

Well actually, thinking about what I said it would never be pumping against itself because you can't get any oil caps without a vent and that would have to be sealed for a vacuum to be created. But if you connect the rocker cover to the carb directly the air won't flow through the engine properly, it's far more important to keep the crankcase clean than the rocker cover.

[bmcecosse]

It's important or remove all the fumes - and yes - if the engine is in good condition, leave one breather open to pull air through - but if it's a bit 'secondhand' and is blowing fumes out - it's best to connect all the breathers together and in to the carb. I have done it directly into the inlet manifold (with a 3mm restrictor) on a high power engine that was prone to fumes and oil leaks when run hard..... The breathers connected to the manifold made a huge difference. The caps I have don't have holes

[liirge]

It's important or remove all the fumes - and yes - if the engine is in good condition, leave one breather open to pull air through - but if it's a bit 'secondhand' and is blowing fumes out - it's best to connect all the breathers together and in to the carb. I have done it directly into the inlet manifold (with a 3mm restrictor) on a high power engine that was prone to fumes and oil leaks when run hard..... The breathers connected to the manifold made a huge difference. The caps I have don't have holes

Really no oil cap you've ever owned is vented? that's odd....pretty sure Dan has already mentioned above that you cant get caps with out a vent in them.,,

[liirge]

BMC....have you actually ever owned an A-series I do wonder sometimes...
http://minispares.co...id=35569&title=
http://minispares.co...id=42603&title=

[Jack BRCG]

thanks il have a think. i thought i could just add one and keep the crankcase breathers on. hmmmm

Can I ask why you are doing this?

i wanted to do it as i get oil leaks at high pressure. all gaskets have been checked and the crank case breathers have been cleaned out.

[liirge]

Is this a 998 or a 1275?