Venting

[cypriot_boy_2k7]

I have read that venting crank or rocker is illegal. So how does everone get around this?

[JF008]

Interesting, until today I've had a crankcase breather, passed 2 M.O.T. But its illegal I think as it may vent exhaust gasses.

Taken from an other forum:

''engine breathers:
on any internal combustion engine (piston or rotary) you get blow-by gasses, which is exhaust gas that's seeped past the piston rings/rotor seals. The majority of the fumes coming out the breather pipes is simply exhaust gas. There's also an element of oil vapour, from the heated aerated oil.

A vacuum source to "pull" the fumes/blowby out is ideal, as it can help reduce internal wind drag on the crank. This is more relevant on high-revving engines than say, a low-lugging diesel engine. But they will happily function at atmospheric pressure, it'll just blow out the fumes from any orifices.

There is no "though-draught" of gasses through the engine as has been described, just a source (the pistons) and a drain (wherever it's plumbed to). This can be either into the intake via a PCV, into the exhaust, or to atmosphere.''

[handpaper]

May be illegal on new cars due to HC emissions, as JF says, oil vapour or droplets. E30s only need to comply with the regulations in force when they were first sold, so I don't think it will be an issue. Hell, the sum of all my oil leaks would dwarf any oil emitted that way!

[cypriot_boy_2k7]

Good info guys. Which brings me to another question. Are out headlights type approved? Or is it illegal to fit HID xenons

[handpaper]

AFAIK, HIDs require a projector headlamp assembly (which we have) to give the right beam pattern and a headlamp wash/wipe to keep the glass clean so it doesn't overheat and crack or interfere with the beam pattern.

[maxfield]

As far as the MOT is concerned, as they're aftermarket bulbs. They dont require headlamp levelling or wash/wipe on the headlights.

[cypriot_boy_2k7]

Nice one guys

[Brianmoooore]

As far as the MOT is concerned, as they're aftermarket bulbs. They dont require headlamp levelling or wash/wipe on the headlights.

They do require a good beam pattern, though, both for the annual test and as a courtesy to oncoming drivers, so post facelift lights only.
BMW engines are designed to work at negative crankcase pressure, so either retain the M52 cyclone arrangement, or vent the cam cover straight to the inlet as per standard M20 or M50. Why would you want to vent. to the atmosphere?

[cypriot_boy_2k7]

Hi Brian I'm saying if you go boosted and you keep all plumbing the same this will make the crankcase be under positive pressure. Venting to atmosphere prevents the pressure build up in the crankcase/rocker.

[Brianmoooore]

So move the pipe to between the air filter and the compressor. There will still be a venturi effect, drawing the gasses from the crankcase.

[E30BeemerLad]

Is there a performance advantage to essentially sucking the crank case gases out?

I'm sure I've read before about guys who vent the crank case breather into the exhaust system after the down pipes and this was supposed to have assisted in a greater power output. Although would this be vastly different from what most of us do with the M50/52 swaps and just direct it into the inlet elbow?

[Brianmoooore]

Mikey_Boy explains it all perfectly in this thread: http://www.e30zone.net/modules.php?name ... light=vent

[cypriot_boy_2k7]

Mikey_Boy explains it all perfectly in this thread: http://www.e30zone.net/modules.php?name ... light=vent

He hit the nail on the head

[craigieeb]

Mikey_Boy explains it all perfectly in this thread: http://www.e30zone.net/modules.php?name ... light=vent

That answers something which has been bugging me.

with my M50 turbo,
I run the oil breather pipe from the rocker cover into a 2 port catch can, then the other exit stub on the catch can i just simply put a little filter on,

yeah it stinks a bit and after having a read through that link, I shall be removing the filter and taking that port/exit down into the top of the sump, or into a port on the dipstick

[cypriot_boy_2k7]

I thought it's was ideal to put it back into the intake, depending on your setup

[Brianmoooore]

I thought it's was ideal to put it back into the intake, depending on your setup

OK on a NA engine, but wouldn't be too clever on a turbo engine, where inlet is at positive pressure.

[cypriot_boy_2k7]

I thought it's was ideal to put it back into the intake, depending on your setup

OK on a NA engine, but wouldn't be too clever on a turbo engine, where inlet is at positive pressure.

On turbo, Positive after turbo, but negative from air filter