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4.0l oiling

bugsie

NAXJA Forum User
Location
tri-cities
Alright first post here we go. i am not new to Cherokees or wrenching for that matter (ase master tech). k so the issue that im having is the motor currently in my 87 is worn out and has a huge amount of crank case pressure and is shooting oil out of the pcv breather and popping grommets left and right. i need a quick fix for this thing to keep this motor going for the next few months as i am almost done with my 4.7l stroker.
 
Is everything in your CCV system flowing freely?

Check the orifice in the back grommet and the lines going to your airbox make sure they are not clogged. There is a writeup on shortening the tubes inside the valve cover on the RENIX jeeps someplace on here, we did that on my old 89 and it really helped too.
 
very clean and clear. i have removed the hose between the airbox and pcv valve because it kept fill my airbox full of oil. on the rear grommet that goes to the vacuum barb on the intake has been enlarged to be a 3/8" barb rather than a 5/16 barb for a the factory 5/32 plastic hose. the grommet is equal size too. the intake is pulling a full 12" of vaccum. at this point i am less concerned about making the factory system work (because honestly it is a terrible design) and more concerned about keeping oil in the damn thing so that i still have a usable core when i am done.
 
Thats about the only easy fix i can think of. As long as those lines are clear and the port in the intake is clear should be ok.

Would valve issues cause this?
 
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the only way you can rig a catch can is with a dry sump system. you have to make an area of low pressure on the pan in order for it to drain into it because of the crankcase being pressurized naturally the oil in the catch can will be pushed back into itself instead of into the pan. and yeah everything is clean and clear. what causes the issue is the clearance between the piston rings and the cylinder walls. the problem that occurs is the piston compresses the air fuel mixture and leaks the pressure down the sides where it is not tight. this is known as blowby causing the pressurized crankcase. i know what the issue is and i know how to fix it properly and that is with a new motor which i am doing. i am looking for one of those quick 48 cent home depot ideas. i dont care how hoky it looks the rest of the jeep is hammered. if i have to vent the crankcase through a pink flamingo stabbed through the hood with the gay pride rainbow flag flapping majestically in the wind above my blazing red and primer chariot. id be good with it.
 
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What about the baffles on the uderside of the valve cover? Are they clean and unclogged? That one plastic line on the back of the valve cover is the usual culprit. I said ta hell with mine and bent up a small brake line piece I had laying around. Works fine for me now, lol. But all the new pieces for the system can be got at the parts store. Might have to go through the dorman/help/motormite book but they do offer them. I sold a few when I was working at the parts stores.
 
What oil (brand and specs) are you running? Have you tried thicker oils, and tried loosening the rings with Gummout and MMO?

Restore might help after running gumout first, then MMO, then Restore.

What are the compression numbers?
 
What oil (brand and specs) are you running? Have you tried thicker oils, and tried loosening the rings with Gummout and MMO?

Restore might help after running gumout first, then MMO, then Restore.

What are the compression numbers?

This.

How much oil was it pushing into the airbox during a typical drive? Sounds like rigging up a catch can for the oil then dumping it back in afterwards might be the way to go.

if i have to vent the crankcase through a pink flamingo stabbed through the hood with the gay pride rainbow flag flapping majestically in the wind above my blazing red and primer chariot. id be good with it.

:roflmao:
 
you can switch vavle covers to a later model (97+) stamped steel cover. They do not have the baffle "towers" inside and do help immensely with oil pickup. You'll need a new gasket and the cover bolts with grommets, and you'll have to replumb your CCV lines a bit. Worked like a charm for me.

Jeff

garage001-11.jpg


comparison of the two covers (see the "towers" on the renix cover.....they are very close to the head surface):

31LTs010.jpg
 
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i did the same thing on my renix mj, though i routed my vacuum lines slightly differently. it works much better, and it passed the brutal ca smog inspection with no troubles at all.

you can switch vavle covers to a later model (97+) stamped steel cover. They do not have the baffle "towers" inside and do help immensely with oil pickup. You'll need a new gasket and the cover bolts with grommets, and you'll have to replumb your CCV lines a bit. Worked like a charm for me.

Jeff

garage001-11.jpg


comparison of the two covers (see the "towers" on the renix cover.....they are very close to the head surface):

31LTs010.jpg
 
i appreciate everyone's input very much. okay some numbers. average comp. psi was 115 and a leak down of about 50%. for how loose this motor is it amazes me it still runs. i like the idea of the new valve cover. i will be doing that with my new motor though it will be changed slightly to accept the dry sump system. my fix is very in that it consists of 10 paper towels and half a role of electrical tape, a bolt in the rear grommet a big o-ring on the fill plug and tape around the dip stick. should work for a month as i want it to. all the time i want to finish my new motor
 
I am going to call fraud, bogus on this photo. This can't be a real jeep, it is WAY TOO CLEAN under the hood, LOL.
garage001-11.jpg
 
i appreciate everyone's input very much. okay some numbers. average comp. psi was 115 and a leak down of about 50%. for how loose this motor is it amazes me it still runs. i like the idea of the new valve cover. i will be doing that with my new motor though it will be changed slightly to accept the dry sump system. my fix is very in that it consists of 10 paper towels and half a role of electrical tape, a bolt in the rear grommet a big o-ring on the fill plug and tape around the dip stick. should work for a month as i want it to. all the time i want to finish my new motor

How about the oil specs?

Mine has been (last tested about 3.5 years ago) around 115-125 psi (COMPRESSION!!!!!! LOL), high to low, on my 87 Wagoneer for 7 years, 276,000 miles right now, and I run 20W50 dyno oil, after running Lucas, and MMO as additives the first couple years to clean it up loosen it up and get better oil pressures, while I fixed everything else. I am getting close to 16 mpg city/hyw average now, and no misses, smooth idle. I run straight 20W50 API SL in it now.
 
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You get 115-125psi of oil pressure. lol. That's how I read it the first time. Hahaha. Then was saying to myself, the last thing was about compression. lol
 
You get 115-125psi of oil pressure. lol. That's how I read it the first time. Hahaha. Then was saying to myself, the last thing was about compression. lol

Cute, LOL, I fixed it in CAPS!!! LOL:loveu:
 
This is also a BIG issue on my Jeep.
I thought I had a rear main seal leak, dripping oil on my exaust. I pulled the cover plate on my bellhousing to see no oil perfectly clean. But my Valve cover gasket was completely blown out not to mention ever port on top of my valve cover Leaking, and my air filter half full of oil. My Jeep passes Smog with flying colors with 220k miles on it so I know my problem wasn't rings or valves.

So looks like I'm in the market for a late model Valve cover and some sea foam.
Great post guys
 
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