12 Valve Rocker Cover Breather

[Andy]

I have read various things about blanking the EGR stuff on 24 valve engines, so, is there any need for the breather pipe from the rocker cover to go into the air intake as the standard setup is on a 12 valve?

Would it make any difference if the breather was disconnected, the hole in the air filter box blanked off & the breather run to just vent to the atmosphere.

I realise that there may be some oil fumes coming out of the breather pipe, so it could be run into a catch pot if neccesarry.

Any thoughts on the advantages or disadvantages, surely it must be better to stop 'dirty fumey' gasses entering the inlet manifold? Or does it help the engine breathe by sucking out the fumes from the top?

Andy

 

[Gav Peter]

There was some discussion of this at the last Lincomb Andy...

Chris, me & Matt were looking at it & I know the others fitted breather/collection tanks in the line as you suggest - mine is still on the bench waiting for me to fit...

I can't quite recall the conversations but Chris will be along to explain in the near future...

Cheers

 

[Chris]

When I bought mine, it had a length of garden hose running into the chassis. Well, all I can say is that the nearside chassis leg will never rust on the inside!! Why anyone did this I don't know. So I now have an oil catcher there instead. This doesn't condense all the 'smoke' and turn it into liquid oil, what it seems to do is catch that actual drips that have already built up in the pipe line. There is s till a light haze that goes into the air intake to be burnt, but you don't get the dribble going in there that I used to get. The real benefits of all this? Honestly, I really have no idea. It's less oily in the pipes now which is nice.

Chris

 

[Andy]

Chris,

So you piped it back up to the air intake with an oil catcher in between then, sounds good, but what I was getting at is when the air intake is sucking hard, & they really do when flooring it!, this will suck more fumes from the rocker cover & 'contaminate the fresh air required for the combustion, thats why I wondered if any benefit by blanking it off.
Maybe I'm just thinking about it too much!!!

Also as I have an intercooler I was wondering if after a long time, the oily residue would just lay in the bottom

Think I will probably just fit a catcher in the pipe run, will look at the boy racer shops on ebay!

 

[Chas]

Chris,Think I will probably just fit a catcher in the pipe run, will look at the boy racer shops on ebay!

Her's the one I bought and not fitted yet so can't comment on how well it performs;

http://cgi.ebay.co.uk/UNIVERSAL-OIL-CAT ... 43a1095e17

 

[tomrichardson]

i had the same thought, in that over time everything gets covered in oil (which it did!). i fitted a water trap from a compressor.its the type with a gauze type filter in the oulet side. seems to work very well and will condensate about a couple of egg cups of oil in say 1000 miles.
when i had the daihatsu i removed the same pipe completely from the inlet and left it belching onto the chassis. this lead the engine to spring oil leaks from the most imaginative places. replace the pipe onto the inlet and no more leaks. hence why i didn't risk it with the cruiser.

 

[Dave2000]

when i had the daihatsu i removed the same pipe completely from the inlet and left it belching onto the chassis. this lead the engine to spring oil leaks from the most imaginative places. replace the pipe onto the inlet and no more leaks. hence why i didn't risk it with the cruiser.

Good point, with the pipe attached to the inlet manifild the crankcase has a 'negative' signal, in theory with the same pipe vented to atmospheric you would expect neither vacuum or pressure however, this may be true of a newer engine but once you put on a few miles there is a slight increase in crankcase pressure which may lead to leaks in particular the 'moving' seals i.e.crank/cam ect.

IMHO the idea of putting in a catch tank 'inline' to the inlet manifold is a good idea, this way your engine is 'seeing' a slightly cleaner charge and you are still complying with emission regualtions if tree hugging is your thing. But if you look at the LC design pretty much most of the oil mist is trapped by the air cleaner so I am unsure if you are going to gain anything. Many cars have the pipe attached direct to the inlet manifold via a bypass valve, there may be more to be gained from that kind of setup but again all this is speculative and dependent on the condition of your engine. Someone mentioned having an intercooler fitted? If you drive like granny for a few thousand miles then there is some (read very small amount) oil sediment resting in the cooler, once you use the loud pedal most of this oil will be pulled into the chambers and you may see a small puff of smoke until the contamination is pulled through but this will last only a few seconds. If you drive pretty hard then the intercooler will stay clean.....ish.

regards

Dave

 

[Chris]

My catcher does not remove the smokey fume - that still goes into the engine. Frankly putting that wisp in there or not won't make a ha'ppeth of difference to the running, but yes it can coat intercooler bits and bobs I understand. As I tried to explain, my catcher get the liquid that has already condensed in the piping and drips, runs into the intake system. It's like a sump trap really. It's not a condenser. It's an oil trap.

Simple installation. Will try to locate a pic.

Chris