PCV removal/ modification

[dunl]

Does anyone have a good thread on modification in order to clean up the engine bay some? Or in order to have it work correctly and not spit oil all over the place? I'm going to get some parts off an 89 XJ for my 89 MJ, so I figured I would grab at least the line from valvel cover (mine is broke). Then I thought....maybe I should look into deleting some of the stuff on there that isn't needed or is robbing some power from the engine.

 

I've looked, but I didn't find a good thread for this.

[Pete M]

I think pretty much everything under the hood has a good purpose and none of it robs any power. :dunno:

 

blow-by is a whole nuther issue. make sure the skinny line going to the valve cover is cleaned out. The late model valve covers can help out too. they have a different baffle system inside.

 

 

oh, and the 4.0 is not a PCV, it's a CCV. there's no PCV valve, just an open elbow. :thumbsup:

[dunl]

I think pretty much everything under the hood has a good purpose and none of it robs any power. :dunno:

 

blow-by is a whole nuther issue. make sure the skinny line going to the valve cover is cleaned out. The late model valve covers can help out too. they have a different baffle system inside.

 

 

oh, and the 4.0 is not a PCV, it's a CCV. there's no PCV valve, just an open elbow. :thumbsup:

 

 

Thanks Pete. I thought that maybe some of the stuff was emissions control. On older Mercedes diesel sedans (especially Calif. models like mine was), the EGR vacuum lines would rob power. There was a pile on top of the valve cover when I started, but three when I finished.

 

So in order to fix the blowby, the line at the back is the only one that really cakes up and needs cleaning? Anything else that can be done to it to improve things?

[sinkrun]

Late model valve cover is the only way to go it will require some mods to the hoses there a topic on here some where?

[Pete M]

most of it is emissions related, but they aren't harmful to power. :thumbsup:

[HOrnbrod]

Pickup an HO cast aluminum valve cover w. the fittings at the yard, clean it up inside (the towers and the CCV valve), and bolt it on to your Renix. Then get the late model vacuum hoses as detailed HERE.

 

This will cure your blow-by problems as long as it's not being caused by something else, like piston rings.

[dunl]

Thanks for the help guys, and for the link Don.

[kazam]

Greetings,

 

I have replaced the plastic valve cover (150 c.i. I-4), 1987 Comanche, with an aluminum cover from a YJ I think it was.

 

I have not fit the vaccum lines yet; I could do with a bit more clarity about how to change that part of the system, PCV, CCV, line routing.

 

The previous link from this tread for more clarity on how to make the switch is out of date.

 

Maybe someone has that information available.

 

Thanks very much.

[omega_rugal]

Does anyone have a good thread on modification in order to clean up the engine bay some? Or in order to have it work correctly and not spit oil all over the place? I'm going to get some parts off an 89 XJ for my 89 MJ, so I figured I would grab at least the line from valvel cover (mine is broke). Then I thought....maybe I should look into deleting some of the stuff on there that isn't needed or is robbing some power from the engine.

 

get / make an oil catch can, oil vapours in the 4.0 are a problem, they clog the oil filter, TB and sometimes they even manage to foul the spark plugs in severe cases... get the can is well worth it...

 

the CCV system itself doesn`t "rob" much power but when it fails and everything gets covered by oil and dust, you do lose power...

 

what about emission? AFAIK modifing the CCV could not make you pass the inspection, if emissions are not an issue you may as well get rid of all EGR related hardware, the egr is there to control NOx emissions at the expense of power

[75sv1]

I just put in a 93-98 ZJ valve cover on my '98 XJ. It has the latter PVC type CCV fittings. I did put on a '95 XJ valve cover on my MJ. I did have to extend the rear CCV line. I think I upgraded to the latter and larger rear CCV line. Also, look at FelPro. They have a gasket that is much better than the cork ones. Its expensive at $35-$50.

[kazam]

I would like to route lines correctly for safe or better vaccum pressure and correct flow of materials.

 

Pretty well I am not attempting to change engine characteristics; I replaced the plastic valve cover with an aluminum valve cover for durability.

 

Some of the fittings are different.

I'll have another look at the engine and my data.

 

Considering engine breathing with sensors that may or may not be CCV or otherwise PCV type-specific,I asked about line routing.

 

I have found there to often (not always) be a draw from the atmosphere of the 'under the valve-cover above the valves atmosphere';

that material then ducted to the air-intake before the air filter; various sensors "consider" the pressure(s).

 

Engine and other systems, run with at least some input of the Manifold Vaccum Pressure, and the "data" of corresponding components: mechanical or otherwise; so I have found.

 

I intend to have another look at what I have.

[kazam]

At M.R. 277, with Informations Service supplements, at B-14 & B-15  (I.S.) are schematic diagrams; both similar; 50 States, Canada.

 

Those do not include explanation of component flow characteristics.

 

 

I scanned a PDF of those pages, and that did not help any.

 

I am working on it.