2.5 aluminum valve cover

[pug]

What years will fit 2.5 not plastic aluminum valve cover. thanks

[JeepcoMJ]

91 and newer, using a 91 and newer gasket as well. you'll need to do some PCV retrofit stuff to make it work.

[pug]

Ok thanks the one i was looking at said it would fit 86 to 90. The other one said 86 to 02

[pug]

I got my (new) used valve cover today. So how hard is it going to be to make the pcv fit on the new cover compared to the old one thanks

[pug]

The valve cover i got came of a 1998 tj. My question is does it matter were i hook up the pvc valve and the other line on the valve cover. Also the old valve cover has valve the new cover just has a elbow in the valve cover. Is thi going to be allright to run this way. thanks

[jteckmann]

The valve cover i got came of a 1998 tj. My question is does it matter were i hook up the pvc valve and the other line on the valve cover. Also the old valve cover has valve the new cover just has a elbow in the valve cover. Is thi going to be allright to run this way. thanks

 

I think it matters.

 

My '86 2.5 has the plastic cover and PCV system. There is a hose that runs from the airbox to the breather filter at the back of the cover. The PCV valve is in the front of the cover, and there is a hose that runs to a port on the throttle body. This is where it gets vacuum, so it draws fresh air from the rear to the front. The valve prevents backflow.

 

You now have a CCV system, which IIRC, works in reverse. The front elbow connects to the airbox, the rear elbow connects to the manifold. Air flows from front to back. There's no PVC valve in this system - the elbows and hoses are different sizes, and that maintains airflow direction.

 

Hopefully someone will correct me if I'm wrong.

[Yesterday's Danish]

Nope that sounds about right. I just replaced my CCV elbows and hoses after doing my valve cover gasket. Might as well change all the elbows, hoses and grommets out while you change the valve cover. Give the valve cover a fresh coat of paint (or 3) too. :thumbsup:

 

EDIT: Go this site www.madxj.com. Under the tech articles, there is one that deals with swapping over the old CCV system to the newer CCV system. You'll have to get a couple new hoses and elbows but it won't break the bank. The newer system is better at preventing blow by, apparently.

[streetjeep2.5]

My '86 2.5 has the plastic cover and PCV system. There is a hose that runs from the airbox to the breather filter at the back of the cover. The PCV valve is in the front of the cover, and there is a hose that runs to a port on the throttle body. This is where it gets vacuum, so it draws fresh air from the rear to the front. The valve prevents backflow.

 

You now have a CCV system, which IIRC, works in reverse. The front elbow connects to the airbox, the rear elbow connects to the manifold. Air flows from front to back. There's no PVC valve in this system - the elbows and hoses are different sizes, and that maintains airflow direction.

 

Hopefully someone will correct me if I'm wrong.

 

:huh???: Ok. My 87 2.5 MJ that I bought with over 200,000 about 7 yrs ago had a plastic valve cover on it with the big hole on the front and it goes to the air box, and the little hole in the back that goes to the vacuum. It never had a PCV in it. :???: Sooooo.... the guy before me put a later cover on it, but still a plastic cover?????? Or, maybe I have a later long block??? :banana:

[jteckmann]

Ok. My 87 2.5 MJ that I bought with over 200,000 about 7 yrs ago had a plastic valve cover on it with the big hole on the front and it goes to the air box, and the little hole in the back that goes to the vacuum. It never had a PCV in it. :???: Sooooo.... the guy before me put a later cover on it, but still a plastic cover?????? Or, maybe I have a later long block??? :banana:

 

IIRC, '86 2.5's were PCV, '87 and up are CCV, aluminum valve cover came along in '91. I think that's the way it went. Sorry my post was worded bad - I didn't mean to imply that all plastic covers were PCV. It's the year that matters, not the material of the cover.

[jteckmann]

pug -

 

One other thing I thought of - the PCV set-up drew air from the bottom (dirty) side of the airbox, and ran it through a breather filter on the back of the cover. The CCV hooks up to the top (clean) side of the airbox, so no separate breather, since it was getting air that had already gone through the airfilter.

 

So when you're setting your new system up, you'll want to either grab the airbox from a CCV-style Jeep that has the hook ups in the right location, or adapt your old one. You don't want the system to be sucking unfiltered air into the engine.

[streetjeep2.5]

Kewl! Thanks for the clarification!

[pug]

Thank for the info will be working on it this weekend.