PCV valve

[Johnnewc]

I have a 1969 f100 with a 302. It is rebuilt with only 8000 miles on it. Upon start up I noticed a rattle, sounded like valve train tick on a cold startup in the morning. Later I noticed a slight rattle at idle and noticed a rougher idle than I remember from last fall. After some investigation I found that at idle the PCV valve was rattling. It is bouncing up and down so fast in the little round housing it is in. The spring is not broken. Then, I noticed when I plug the PCV valve while the engine is running I get a lot of vacuum on my finger which is normal I think. When my finger is plugging the PCV valve the engine smooths out and runs better. So what's the deal? The PCV valve was new when I put it in. I'm guessing it went bad since it is a serviceable part. It must be made of junk if it went bad that quick. Does anyone have any other thoughts on this issue? Thank you for your help.

[yellercat]

John, my understanding about the PCV valve is that when it rattles, that it is good.
Not sure about your other symptoms, but would look for other possibilities.

[QC]

You may have a vacuum leak somewhere else or you could possibly have the wrong pcv valve. There are many that look the same but are metered differently.

[Johnnewc]

I replaced the PCV valve with a new one that I knew was correct for the engine. It runs a lot better now. I think there was something wrong with the spring in the old one. Thank you for everyone's help.