Front breather

[cpttuna]

I recently replaced the fron valve cover grommet. When I did this,I removed the old line going to the air box and installed a new breather. I had to buy a hose connector(O'Reilly part #28609) FOR $2.99. this lets you go from 1/2 to 3/8. the breather has a 3/8 inlet(O'Reilly part #SPT 3998). It cost $9.99. the air gets in a lot quicker now. I have only seen this mod done on a couple of cherokees.

http://i953.photobucket.com/albums/ae20/link803/picsnov09123.jpg

http://i953.photobucket.com/albums/ae20/link803/picsnov09114.jpg

http://i953.photobucket.com/albums/ae20/link803/picsnov09113.jpg

[xj4life2]

Pictures , pictures, pictures

[wv jeeper]

I did this on my 94 toyota and it saved alot of oil from gumming up the throttle body, great mod. I'm going to do my cherokee when the 4.6 is finished.

[BlueXJ]

I think it was meant to have the vacuum from the intake to suck the fumes from the valvecover into the system to be burned along with the fuel and air mixture. This completely defeats that purpose.

[Mudderoy]

I think it was meant to have the vacuum from the intake to suck the fumes from the valvecover into the system to be burned along with the fuel and air mixture. This completely defeats that purpose.

So the direction of the air flow is to the air intake and not to the valve cover? That would mean this mod is exhausting the valve cover. hmmmm

[BlueXJ]

No, the valvecover has a neutral pressure under normal circumstances. The hose from the intake to the valvecover created a negative pressure (vacuum) which purged the fumes and oil mist into the intake to be burned.
Now the vent filter should still be keeping trash from entering the valvetrain but would allow any pressure buildup to be vented to the atmosphere. This would be indicated by the filter being wet with oil or actual drainage of oil.:shocker:

[cpttuna]

based upon the comments made since I started this post, i decided to talk to my mechanic. i told him what i had done and he told me that was not a good idea. it was inhibiting the vacuum in the engine ccv system. as a result, i'm going back to what i had there before.

[Mudderoy]

based upon the comments made since I started this post, i decided to talk to my mechanic. i told him what i had done and he told me that was not a good idea. it was inhibiting the vacuum in the engine ccv system. as a result, i'm going back to what i had there before.

Hey thanks a lot for that. I thought it was a pretty good idea, with the exception of any high water crossing. It's great we can discuss this stuff share ideas and hopefully the end result is better for all of us. That certainly sounds like what happened this time.

[rguignard]

I think it was meant to have the vacuum from the intake to suck the fumes from the valvecover into the system to be burned along with the fuel and air mixture. This completely defeats that purpose.

blue isnt that what the pvc valve is for ? i might be missing something but does the 4.0 have a pvc valve ?

[Mudderoy]

blue isnt that what the pvc valve is for ? i might be missing something but does the 4.0 have a pvc valve ?

Mine doesn't. I think they stopped having them in the 97+

[XJ4IV]

Not sure but there is a valve going from the back of the valve cover with a hose that goes to the intak plenum I have had a few tell me that it creates a vacuum and pulls the excess valve cover pressure and sends it back through the intake ... Not sure about this but it SEEMS like that could be the case. MINE does the same thing which started this thread with the little filter on the valve on the front cause I did a cold air intake thingy which didnt have a spot for the hose to be attached, My thinking is that as long as I filtered the air going into the valve cover then I was OK now reading this thread I think I may have found the reason WHY im spewing oil out of my dipstick... as my little filter is CAKED with oil but I was glad I was not caking up my K&N