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Looking for this hose for this breather hose solution..any idea what it is?


jrhone

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It's too bad the M10 has such a dinky little baffle in the valve cover.  A lot of oil carry-over in the vent could be eliminated if it had a better baffle.  The M20 runs the entire length of the cover, the S14 covers most of the inside area of the cover.  Later engines separate the oil and send it back to the crankcase, the water vapor and blowby gasses are run thru the engine.  If the oil sump is hot enough any moisture escapes as vapor and is the main reason for not running oil temps less than 175F.

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  Later engines separate the oil and send it back to the crankcase, the water vapor and blowby gasses are run thru the engine.  If the oil sump is hot enough any moisture escapes as vapor and is the main reason for not running oil temps less than 175F.

 

Aww yes, the crankcase oil separator.  And if not allowed to get hot enough by driving short trips and then parked outside in subfreezing weather, the valve can freeze up, building up pressure and either blowing out the valve cover gasket spewing oil all over the exhaust manifold or blowing oil into the cylinders. I've had both happen to my M52 TU engine. First time it happened it caused an engine compartment fire that I was able to put out before any permanent damage and the second time it happened two years later, it pumped oil into the cylinders at a stop sign causing the biggest cloud of black smoke I have ever seen come out of a car. I thought I blew the engine.

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Hey

 

Another solution and the one I have used on my cars is running a length of heater hose down past the engine on the carburetor side to just below the subframe. Any oil either returns to the engine or drips out the hose. That said, my garage floor is spotless   :) Honestly, I did initially go for the breather filter on this latest resto because it looks good...until I noticed a leak; it freaked me out; I thought my rear seal was blown. 

 

Sorry no pictures.

 

Regards

Bill P

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It's too bad the M10 has such a dinky little baffle in the valve cover.  A lot of oil carry-over in the vent could be eliminated if it had a better baffle.  The M20 runs the entire length of the cover, the S14 covers most of the inside area of the cover.  Later engines separate the oil and send it back to the crankcase, the water vapor and blowby gasses are run thru the engine.  If the oil sump is hot enough any moisture escapes as vapor and is the main reason for not running oil temps less than 175F.

 

Any high compression/turbo engine will have some blow-by during heavy load/high RPM, but if it is excessive or happens during normal street driving, then you may have a ring sealing issue.

 

I am a believer in well-designed breather systems with the crankcase vented to the intake system. This helps to maintain a vacuum in the crankcase, which helps with ring sealing in high compression/turbocharged engines (many high-HP V8 drag race engines use a mechanical vacuum pump to achieve the same effect; this is also huge benefit of the large scavenge setup of a full dry-sump oil system). The downside of this breather arrangement is that oil/moisture from the crankcase is introduced into the engine, which not only may make a mess inside the intake system, but can also dilute the air/fuel mixture and lower the effective octane rating of the fuel.

 

The answer is to employ some form of air/oil separation inside the catch can (mesh screen, steel wool, etc) to physically separate the oil droplets from the air before it enters the intake. For this reason, I like this brand of catch can:

 

http://www.saikoumichi.com

 

Though I am sure that one could rig up something similar using a cheapo Ebay can . . . . . or a Gatorade bottle :)

 

Aww yes, the crankcase oil separator.  And if not allowed to get hot enough by driving short trips and then parked outside in subfreezing weather, the valve can freeze up, building up pressure and either blowing out the valve cover gasket spewing oil all over the exhaust manifold or blowing oil into the cylinders. I've had both happen to my M52 TU engine. First time it happened it caused an engine compartment fire that I was able to put out before any permanent damage and the second time it happened two years later, it pumped oil into the cylinders at a stop sign causing the biggest cloud of black smoke I have ever seen come out of a car. I thought I blew the engine.

 

Yikes, did you update to the factory insulated/foam covered "cold weather" versions of the crankcase vent valve and hoses after the first failure? They are supposed to help that issue somewhat (I have never seen this at my shop in SoCal, though we hear about it often from fellow shops in the snow belt), but it probably isn't foolproof. In fact, BMW went a step further by electrically heating the crankcase vent valve of the '06 N-series engine, then moved it inside the valve cover for the '07 and up plastic valve cover models (which means that the entire valve cover needs replacement if/when the valve fails!).

 

Regardless of the exact setup, most modern German engines use some form of (failure-prone) crankcase pressure regulating valve, which as its name implies keeps crankcase vacuum as constant as possible during all engine conditions/loads. This is mainly for emissions reasons, and is not necessary in an old hot rod BMW engine. Simply install a good oil separator/catch can in-line with the breather hose between the valve cover and throttle body and empty it periodically.

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Yikes, did you update to the factory insulated/foam covered "cold weather" versions of the crankcase vent valve and hoses after the first failure? They are supposed to help that issue somewhat (I have never seen this at my shop in SoCal, though we hear about it often from fellow shops in the snow belt), but it probably isn't foolproof. In fact, BMW went a step further by electrically heating the crankcase vent valve of the '06 N-series engine, then moved it inside the valve cover for the '07 and up plastic valve cover models (which means that the entire valve cover needs replacement if/when the valve fails!).

 

 

 

 

It was eight years ago the first time it happened. I had it towed to Ben T's shop to be fixed. I don't know if the insulated "cold weather" kit was available then, he didn't mention it. When it happened a couple of years later, I know he put the "cold weather" kit on and it hasn't happened since but I'm still leery of it happening again.

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