Blow-by

[supervisor1886]

I was wondering here. Is it common for E21 block to produce somewhat more blow-by than other, say, american engines? Well, mine has 180psi on all cylinders, pulls hard,doesnt use any oil,no slage at all (has a little knock cause one of the rockers and the shaft is worn, i adjusted the valves to lower specs, so it ticks just a little). But the blow-by is pretty hard. (no blue smoke, but I can feel the gas pressure) . I dont have any emission junk on it, and no crank ventilation too-it just vents into the air. Maybe I am sowhat biased too becasue I am used to v6 and v8 and they dont build up as much pressure.

What kinda blow-by do you have on yours? Mine is a 1982 1.8 block, for now it will get dual Solex carbs and later a Chevy 305/t5 swap.

[supervisor1886]

anyone?

[supervisor1886]

WTF. noone has blow-by anymore?

[daniel 61]

Originally Posted by supervisor1886

I was wondering here. Is it common for E21 block to produce somewhat more blow-by than other, say, american engines? Well, mine has 180psi on all cylinders, pulls hard,doesnt use any oil,no slage at all (has a little knock cause one of the rockers and the shaft is worn, i adjusted the valves to lower specs, so it ticks just a little). But the blow-by is pretty hard. (no blue smoke, but I can feel the gas pressure) . I dont have any emission junk on it, and no crank ventilation too-it just vents into the air. Maybe I am sowhat biased too becasue I am used to v6 and v8 and they dont build up as much pressure.

What kinda blow-by do you have on yours? Mine is a 1982 1.8 block, for now it will get dual Solex carbs and later a Chevy 305/t5 swap.

I do not have blow-by on my E-46,but common problem on older BMW is blue oil smoke coming from the tailpipe while coasting down off throttle from high speeds. This is an indication of bad valve seals and worn valve guides. This problem is liveable, just as long as the oil level is checked regularly. Lots of crankcase blowby is an indication of loose rings, and is often accompanied by oil smoke from the exhaust while idling and accelerating. The E21 engines are tough, and it is usually the head that needs the most work during rebuild time. Rocker arms and shafts suffer from wear and usually need replacement if the head has over 100,000 miles on it. Valve guides almost always need replacement as well.I would not worry much about it, live with that.

D.

[daniel 61]

BTW what are you supervising ? LOL..

[supervisor1886]

That was a lie about the blow-by. You dont really notice it since you got PCV. I had a second look and it looks fine. The engine is pretty healthy. and if you compare the amounts of gas produced by a v8 and a 4 at idle, it looks like its almost the same quantity (4 banger fires the same amount of times at 1000 RPM as a v8 at 500RPM like mine does, but the 4 banger is smaller and builds up a little pressure). And it looks like the pipe was made to remove some serious blow-by there. I agree with what you say about those engines, everyhing is true. So we could add a case of blow-by to it as well. (based on my own mechanical knowlege).


Iam supervising whatever you want. (the name was created as a joke on one of my friends at the time back in 2004) I also go by Dick Steele and whole bunch of other names.

[daniel 61]

Originally Posted by supervisor1886

That was a lie about the blow-by. You dont really notice it since you got PCV. I had a second look and it looks fine. The engine is pretty healthy. and if you compare the amounts of gas produced by a v8 and a 4 at idle, it looks like its almost the same quantity (4 banger fires the same amount of times at 1000 RPM as a v8 at 500RPM like mine does, but the 4 banger is smaller and builds up a little pressure). And it looks like the pipe was made to remove some serious blow-by there. I agree with what you say about those engines, everyhing is true. So we could add a case of blow-by to it as well. (based on my own mechanical knowlege).


Iam supervising whatever you want. (the name was created as a joke on one of my friends at the time back in 2004) I also go by Dick Steele and whole bunch of other names.

Cool ! Reason I was asking my stupid "Polak" curiousity.Im half polish, another "canadian speciality".

[sirhada]

both of my bmw's have had a lot of blow by.but the odometer stopped at around 300,000 miles too!