case and head vents, do I need to run a breather box? Options

[wayne1234]

Ok dual webber carbed 2.0, I think the PO had the head vents running to a T then to the oil breather near the oil cap... Is this right?? I did a search and now I'm really confused,,,,

[HAM Inc]

You know Murray, for a guy who was building engines when Jake was pooping yellow you sure have a weak grasp of theory.
Oil cools the valve springs, not air. But I will concede that in as much as the heat that the oil draws from the springs and rockers is generated by the heads one could accurately state that the oil does cool the heads. But it's BTU absorbing capacity is not up to the task of drawing a significant amount of heat out of the heads, so it only benefits the springs and rockers. Which brings me back the point about unvented heads running slightly cooler oil temps.

I'm not interested in going down the line point by point by point with you as you clearly have made up your mind.
But I will point out one commonly held misconception that you suffer with yourself, further indicating that your understanding of engine theory is very elementary.

Hotter the springs=loss in valve seat pressure.=shorter valve spring effective pressure/life. Ok .(solution)..so just increase installed seat pressure..=...that increases rotational force...just to turn over the engine. (use torque wrench to conferm.).

The cam loading at speed is nothing like what it is at assembly. At near redline speeds the load on the cam at max lift (as the lifter goes over the nose of the lobe) may be 5 lb's it may be near 0. At speed the greatest load that the cam sees is when the lobe encounters the stationary valve train and has to get it moving...and in a hurry. This is why higher rev engines want a higher spring rate (not to be confused with seat or open pressures). And it is why turning an engine over with a torque wrench to gain some understanding of the value of different spring rates AND pressures is useless.
I pass this forward not to educate you (you already know it all) but to inform the community at large who have a real interest in these things and because they are not experts like you are willing to learn.
I have not stepped in in the past when you have made post' that spread misinformation, it's just not my style, but on this subject you have attacked my credibility and the findings of an exhaustive study done by professionals. And I will point out to you that I have nothing to gain if people vent or don't vent their heads. I'm not selling breather systems.

Folks be very wary of taking advise from this guy.

[ME733]

You know Murray, for a guy who was building engines when Jake was pooping yellow you sure have a weak grasp of theory.
Oil cools the valve springs, not air. But I will concede that in as much as the heat that the oil draws from the springs and rockers is generated by the heads one could accurately state that the oil does cool the heads. But it's BTU absorbing capacity is not up to the task of drawing a significant amount of heat out of the heads, so it only benefits the springs and rockers. Which brings me back the point about unvented heads running slightly cooler oil temps.

I'm not interested in going down the line point by point by point with you as you clearly have made up your mind.
But I will point out one commonly held misconception that you suffer with yourself, further indicating that your understanding of engine theory is very elementary.

Hotter the springs=loss in valve seat pressure.=shorter valve spring effective pressure/life. Ok .(solution)..so just increase installed seat pressure..=...that increases rotational force...just to turn over the engine. (use torque wrench to conferm.).

The cam loading at speed is nothing like what it is at assembly. At near redline speeds the load on the cam at max lift (as the lifter goes over the nose of the lobe) may be 5 lb's it may be near 0. At speed the greatest load that the cam sees is when the lobe encounters the stationary valve train and has to get it moving...and in a hurry. This is why higher rev engines want a higher spring rate (not to be confused with seat or open pressures). And it is why turning an engine over with a torque wrench to gain some understanding of the value of different spring rates AND pressures is useless.
I pass this forward not to educate you (you already know it all) but to inform the community at large who have a real interest in these things and because they are not experts like you are willing to learn.
I have not stepped in in the past when you have made post' that spread misinformation, it's just not my style, but on this subject you have attacked my credibility and the findings of an exhaustive study done by professionals. And I will point out to you that I have nothing to gain if people vent or don't vent their heads. I'm not selling breather systems.

Folks be very wary of taking advise from this guy.

.....................Yes be wary of taking advice from people who avoid answering "exactly and precisly how you observed ...." and degenerate into a panicky state of personal generalities to avoid answering the stated facts....AND if you can be believed apparently a compressed valve spring has 5-to 0 ft lbs of torque at full compressed height.(valve fully open)(on the nose of the cam).... surely this too was a typo error...(seems like you guys are just digging your hole deeper). who knowes maybe you enjoy self induced flagulation.....Murray..