valve covers

sprink669

THis may be a dumb question but I have one about valve covers. Why is that on some have breathers and some do not have them? I am going to buy new covers for my AMC360. THe ones that I took off of the donor motor did not have any breathers. My guess is going to be I do not have to get the ones with breathers.

jeepsr4ever

Stock AMC system has the breather in the oil cap and the rear PCV valve. For performance breathers in the valve covers should be added.

BREK

If you want breathers in your valvecovers you will have to have them custom made. None of the replacement amc valve covers that I have ever seen have a breather in them.

northplainsdrifter

jeepsr4ever wrote
Stock AMC system has the breather in the oil cap and the rear PCV valve. For performance breathers in the valve covers should be added.

Why do you need more breathers on a performance engine? Is the two not enough to pull all the blow by out?

ironman_gq

not necessarily. If you have a blown or turbo engine you will have a lot more blowby than normal and some engines with worn cylinders or rings have a lot of blow by and the stock breather isnt enough.

BREK

So on my n/a engine could I be venting to much causing the rings to not seat properly?

ironman_gq

that shouldnt cause trouble unless you are pulling dirt and moisture in through the breathers however some crank case vacuum can help with ring seal and reduce oil contamination with soot and unburned fuel. It seems counterintuitive that having vaccum on the case would help keep pressure in the cylinders but it works.

BREK

Well I have had a little oil consumption issue. Maybe I will try pluging the valvecover breathers and see what it does.

sprink669

thanks for the help I just have seen it both ways and wondered what was the best to go with? I am going to put a order in for the AMC covers.