32 replies to this topic

[Fispop]

Don't just re think about the speed the pistons don't pump the air in the crank case, sure it moves the air about but doesn't pump it, theres no valves

That's it in a nutshell. Piston presure.

This topic started by someone asking about a breather pipe, I answered the question to the best of my knowlage having researched this myself in the past, someone then asked to explain this in more detail, again I tried my best from my knowlage of this, I mentioned about an engine reving upto 8,500 revs.

People then make comment about the revs quoted, I said upto 8,500 revs not mentioning engine size.

Then go on about VALVES? What has valves got to do with a breather pipe, and mention crank case, a Mini does not have a crank case, it is the gear box below the Crank so it's the gearbox where the presure is built up, inline engines hav Crank cases.

But what has any of this to do about the bratherer pipe?

People on this forum just seem to want to try and ridicule others by commenting on there comments, the origional question then is forgotten ie, upto 8,500 upto can be from zero to 8,500 revs, do they not understand "upto" Thick or what.

I don't think that I will ever bother trying to help someone else on this Forum because others don't take it serious and just like to wind people up.

Good bye.

[CityEPete]

Well it helped me, I had to make a diagram to work out the order of firing and think about what does what etc :)

[andy159]

may i add it also aides against fumes and smells in the engine bay if its connected to the carb

[Gremlin]

Don't just re think about the speed the pistons don't pump the air in the crank case, sure it moves the air about but doesn't pump it, theres no valves

That's it in a nutshell. Piston presure.

This topic started by someone asking about a breather pipe, I answered the question to the best of my knowlage having researched this myself in the past, someone then asked to explain this in more detail, again I tried my best from my knowlage of this, I mentioned about an engine reving upto 8,500 revs.

People then make comment about the revs quoted, I said upto 8,500 revs not mentioning engine size.

Then go on about VALVES? What has valves got to do with a breather pipe, and mention crank case, a Mini does not have a crank case, it is the gear box below the Crank so it's the gearbox where the presure is built up, inline engines hav Crank cases.

But what has any of this to do about the bratherer pipe?

People on this forum just seem to want to try and ridicule others by commenting on there comments, the origional question then is forgotten ie, upto 8,500 upto can be from zero to 8,500 revs, do they not understand "upto" Thick or what.

I don't think that I will ever bother trying to help someone else on this Forum because others don't take it serious and just like to wind people up.

Good bye.

Don't have a go at me, I was correcting you, not having a go at you, so that the OP was not mislead, don't make it sound like I was suddenly going on about valves, it was valid to what I was saying, as I said, the pistons do not build up pressure just by moving

[Steve-O 2014]

loads of info to read lol… The breather coming out of the engine is at the rear right and its sort of like a 5 - 6 inch black cylinder. is this like some sort of stock catch can tank? You can just see it in this pic (the bit with the little filter on)

 

Edited by Steve-O 2014, 30 May 2014 - 08:18 PM.

[Minigirl]

Heres a pic I found from google, Should I just connect this direct to the carb? - 

 

[CityEPete]

Thats how my 998 is with a standard HS2 Carb, one pipe from the top of the canister to the side of the inlet manifold on mine.

[Minigirl]

ok, I will do that and see if it eliminates the oil leak issues before stripping things down and fitting new seals as oil is coming from all sorts of places...

[CityEPete]

As long as the canister was not blocked up then it will have still been venting out possibly with some oil but it wont have held any pressure to make the other seals leak, oily hands time again, Lol.

[l_jonez]

If its full to the brim from blow by and a piston comes down on a suck stroke it will increase the crankcase pressure, some air will try to go up the cylinders on squeeze and blow but the opposing cylinder to the one sucking is on its bang stroke creating even more pressure from blow by. If my laymans understanding is correct?

If you have enough blow by to increase the crankcase Pressure enough to effect the seals then I'd be more worried about the piston rings/bores than a breather.

[CityEPete]

I agree,I don't think I've suggested otherwise? Moving the breather isn't going to stop oil leaking anyway as it wasn't capped off before.

[Minigirl]

well the breather canister seems free flowing, attached a pipe and blew down it and could hear air at the oil cap area

[Island Mini]

Sorry to chime in here I don't want anyone feeling like there is an attack going on here but surely the pressure increase mentioned would only occur if the breather hoses are blocked or plugged. The breather hoses would be the point of weakness you are talking about hence a reason they exist So I would say in my opinion as long as they aren't blocked its not going to do damage. I would stick them in the carb if there is a place for it if not just leave your filter on the end of some hose to stop any debris entering.

Hope maybe I didn't make things worse.
Toby

[Captain Mainwaring]

 

Don't just re think about the speed the pistons don't pump the air in the crank case, sure it moves the air about but doesn't pump it, theres no valves

That's it in a nutshell. Piston presure.

This topic started by someone asking about a breather pipe, I answered the question to the best of my knowlage having researched this myself in the past, someone then asked to explain this in more detail, again I tried my best from my knowlage of this, I mentioned about an engine reving upto 8,500 revs.

People then make comment about the revs quoted, I said upto 8,500 revs not mentioning engine size.

Then go on about VALVES? What has valves got to do with a breather pipe, and mention crank case, a Mini does not have a crank case, it is the gear box below the Crank so it's the gearbox where the presure is built up, inline engines hav Crank cases.

But what has any of this to do about the bratherer pipe?

People on this forum just seem to want to try and ridicule others by commenting on there comments, the origional question then is forgotten ie, upto 8,500 upto can be from zero to 8,500 revs, do they not understand "upto" Thick or what.

I don't think that I will ever bother trying to help someone else on this Forum because others don't take it serious and just like to wind people up.

Good bye.

 

 

 

Hmm. yep.

Well I did give you a clue - a triumph twin will pump air but a mini engine won't. Why? In a Triumph twin the crankcase volume is constantly changing dependent of the crank angle whereas in the mini engine it's constant. Doesn't matter what the engine speed is or the size of the engine (to the best of my knowlage [sic] )

 

It's said that there are no stupid question (though I beg to differ reading some of them that are posted) - but as sure as the Lord made little green apples there are some pretty dumb answers.

 

 

So to put you right, it's very important to understand what goes on inside the crankcase to understand what the breather system has to cope with, and the mini engine is a constant volume engine whereas a Truimph twin is not. The mini breather system has to cope with piston and valve guides blow by, whereas a Triumph breather has to cope with varying crankcase volume - You understand it yet?

 

And yes, a mini has a crankcase - it just happens to have  few gears and junk dropped in it, but it's definitely a crankcase.

 

 

"People on this forum just seem to want to try and ridicule others by commenting on there comments,"

 

With all due respect, some people do a perfectly good job of ridiculing themselves without an external assistance  

[Dan]

Sorry to chime in here I don't want anyone feeling like there is an attack going on here but surely the pressure increase mentioned would only occur if the breather hoses are blocked or plugged. The breather hoses would be the point of weakness you are talking about hence a reason they exist So I would say in my opinion as long as they aren't blocked its not going to do damage. I would stick them in the carb if there is a place for it if not just leave your filter on the end of some hose to stop any debris entering.
Hope maybe I didn't make things worse.
Toby

No that's not the case. All crankcases will pressurise from blowby and heating if left to open venting unless the vent holes are massive. The small outlet from the canister can't keep up and more importantly the tiny openings between the various different chambers inside it really can't so the different areas inside will sit at different pressures. This is where oil leaks come from. All modern production engines use positive ventilation, it's a system that has developed over the years starting from trying to use road draft under the engine to form a Venturi to draw fumes out of the engine. If you want to take your engine back to the 1930s by all means do away with all ventilation equipment and just leave filtered holes all over it! But rest assured you will get more oil leaks, your oil will break down quicker and your engine compartment will be filthy. This is not opinion. Many members here have fixed persistent oil leaks by simply reconnecting the system their engine was designed with that a previous owner had replaced with a shiny filter.