I need some advice on blowby

[Virginia]

My comanche has 178K miles on it, needs either a master or slave cylinder and has major blowby telling me it needs a ring job. How much am I looking at pumping in to her to fix all of that and is it worth it? If I were to sell her now, how much do you think I could get?

 

What would you guys do?

[Geonovast]

Blowby doesn't necessarily mean rings. It's very common for the CCV system to get gummed up and fail, causing blowby.

[Virginia]

I've checked the little tube that comes off the top of the valve cover and that's clear. What else gets gummed up?

[mountainman]

if you think you have excess blowby, build the setup and do a crankcase pressure test.

I don't know what the standard spec is but I'm sure you could find whats normal for most engines, by googling it and studying. :)

[HOrnbrod]

Pull the valve cover. There's a plastic fitting in the rear hole with a pinhole in the middle that meters the internal pressure. If commonly gets clogged and causes blowby. Clean or replace it,then clean up the inside of the cover and the vent towers.

[Automan2164]

Pull the valve cover. There's a plastic fitting in the rear hole with a pinhole in the middle that meters the internal pressure. If commonly gets clogged and causes blowby. Clean or replace it,then clean up the inside of the cover and the vent towers.

 

Bam!

 

X2.

 

Rob

[Virginia]

Pull the valve cover. There's a plastic fitting in the rear hole with a pinhole in the middle that meters the internal pressure. If commonly gets clogged and causes blowby. Clean or replace it,then clean up the inside of the cover and the vent towers.

 

Will do, and thanks.

[cruiser54]

Maintain your CCV system as mentioned, and do this:

 

Cruiser’s Valve Cover Mod

 

Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.

 

 

Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.

[Virginia]

Awesome! Thanks

 

Maintain your CCV system as mentioned, and do this:

 

Cruiser’s Valve Cover Mod

 

Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.

 

 

Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.

[ParadiseMJ]

I thought my CCV was clear too.

 

When I pulled the VC apart I found this. Looks like a disease or something. The orofice was puckered shut.

 

 

This is what the inside of the CCV should look like. The metered orofice is 2.5 mm.

 

 

Cruisers mod works nice, I just did it on the VC towers on my XJ.

[Virginia]

The pictures didn't load for me.

[cruiser54]

I thought my CCV was clear too.

 

When I pulled the VC apart I found this. Looks like a disease or something. The orofice was puckered shut.

 

 

This is what the inside of the CCV should look like. The metered orofice is 2.5 mm.

 

 

Cruisers mod works nice, I just did it on the VC towers on my XJ.

 

 

It is a disease: Orifice Puckeritis.

[Zebvance]

I thought my CCV was clear too.

 

When I pulled the VC apart I found this. Looks like a disease or something. The orofice was puckered shut.

 

 

This is what the inside of the CCV should look like. The metered orofice is 2.5 mm.

 

 

Cruisers mod works nice, I just did it on the VC towers on my XJ.

 

 

It is a disease: Orifice Puckeritis.

 

I payed a guy to replace my valve cover gasket and both hoses out of the top of the valve cover when I first noticed I had blow by, the guy didn't see that I had bought a new back hose and orfice, so he didn't put it on , but he said he cleaned it when he pulled the VC off. Now if he did actually do that I don't know. But I still had blow by bad, it seemed as if it might have even gotten worst after I got it back. I didn't want to pull the valve cover back off to replace that hose because I put a $50 felpro VC gasket on it and I didn't want to have to by a new one, so I just went and got a oil catch can for cheap on e bay and just hooked it up, I haven't had a chance to see if it's doing its purpose yet because I have not drove the mj cause I'm still in the middle of replacing the radiator right now but I hope it works. The truck has 101,000 miles on it and runs great though, it does not burn oil at all and exhaust is clear as could be, to me it shows no signs of worn rings but I can't confirm 100% without doing a compression test on each cylinder, which I haven't done yet.

[Eagle]

I've checked the little tube that comes off the top of the valve cover and that's clear. What else gets gummed up?

The valve cover.

[cruiser54]

I've checked the little tube that comes off the top of the valve cover and that's clear. What else gets gummed up?

The valve cover.

 

And grommet gets puckered.

[mountainman]

So would a 91 have this also? cause my rear main is seepin and if i have this issue and crank case pressure is up... may be my cause.

This thing is UNDER the valve cover? under one of the in/outlets? anyone have a pic of where this part is on the VC?

 

I love this type of stuff. Thanks guys.

[Zebvance]

So would a 91 have this also? cause my rear main is seepin and if i have this issue and crank case pressure is up... may be my cause.

This thing is UNDER the valve cover? under one of the in/outlets? anyone have a pic of where this part is on the VC?

 

I love this type of stuff. Thanks guys.

 

 

yes, that could be the use but also if your piston rings are gone it also causes pressures to go up and will start making gaskets fail. correct me if I am wrong guys...

[cruiser54]

I have a photo but can't post it up. Help!!!!

[cruiser54]

So would a 91 have this also? cause my rear main is seepin and if i have this issue and crank case pressure is up... may be my cause.

This thing is UNDER the valve cover? under one of the in/outlets? anyone have a pic of where this part is on the VC?

 

I love this type of stuff. Thanks guys.

 

 

yes, that could be the use but also if your piston rings are gone it also causes pressures to go up and will start making gaskets fail. correct me if I am wrong guys...

 

 

More than likely NOT rings.

[mountainman]

no not likely the rings, i agree. I just think the rear main is hard as a rock and so its starting to leak.

at 186k.... id expect that as normal.

It didnt leak till this last long road trip. Where i ran it loaded as hell for 9 hours straight.

Seems it didnt like that. But it doesnt use a drop of oil and the airbox is bone dry.

So i just think its the RMS. :) Which i will be changing very soon.

[cruiser54]

I'd be looking up above first, and VERIFYING the source of the oil leak yourself. Many mechanics, friends, and good old Uncle Bob love to tell you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it? A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon just yet.

 

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.

 

First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

 

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

 

Revised 8-15-2012

[mountainman]

looked cruiser. Engine is 100% DRY everywhere. But seeps from the bell housing every time its shut down.

 

Back of valve cover.. DRY *check*

 

Oil fillter mount... DRY *check*.

 

So I'm prob gonna change the RMS just cause it has 186k on it.

 

My only debate in my head now is, do i change the oil pump while in there.. or leave it.

 

:hmm:

[cruiser54]

I would replace the pump. I use th ehigh volume pump as it's only a few bucks more and comes with a new pickup tube and screen-a $36 value alone.

[mountainman]

Thats what i was thinking. But i have 60 psi at cruise and 40 at idle. lol. No real reason to change it.

BUT.... ill be in there. May as well.

[Virginia]

I have the valve cover off and the two pipes that look like triangle chimney stacks are off. When I took them off, there's a brass looking gasket but there was also something that appeared to be a gasket between the brass piece and the valve cover. It was hard and crumbled. I had to scrape it off with my screwdriver. What was that and does it need to be replaced?

 

Also, there's already a hole in the tube facing the back. I'll cut the pipe down and clean out the holes already there. I see nothing plastic with a pinhole in it.