Green Acres and Todd are both corect.
As the cylinder moves it creates high and low preasure in the crank case. The breather acts as a check valve, only leating air move one way, out of the crank case.
There are 2 differnt valves on the commands that Ive seen. Cant remember but one gives much more problems than the other. If I remember right it was on the engs with the spark advance modual, most times you see it called a SAM unit.
On another note I have a friend that has 10 vanguards in carpet cleaning trucks. He called me about one that was blowing a lot of oil and the air fitler was covered in oil. With him in Pa I cant bring it in and do a leak down test on it. But what really was the key, oil on the air filter. After many phone calls I sent him a breather and he put it on. Now it runs much better, no more oil blowing out the seal.
He dosnt know much about engs, but he was ready to put another eng on this van. after a week of running he called me to let me know how it was running, and said he couldnt belive that that little thing could cause so much trouble.
|