[80cj]

so i finally got around to putting on the aluminum valve cover and i thought that would fix the oil problem. but it is still dumping oil out of the breather on the valve cover. i have replaced the pcv valve. i checked the vaccum going to it (around 20 at idle then climbs to 28ish). the valve cover has baffles. oh yeah - it is a 258, approx 30K on rebuilt engine. no emissions. on the pcv valve, i have vacuum going to one side of the T and the other side is capped. i'm stumped. what would happen if i got rid of the breather? the oil spots on the driveway are getting very old. any suggestions?

thanks all
shawn

The cup isn't half full or half empty, it's just twice the size it needs to be!!!

 

[GeeAea]

Get K&N oil breather or go to Summit and search under "oil systems" and look at their catch cans w/breathers.

GeeAea

Now that I've quit smoking my doctor informs me that I'll die in much better health!!!

 

[80cj]

so you think it is a breather problem and not an indication of something bigger? i have a 'Mr Gasket' breather on there now. i know it is a cheapy, but what will a 'better' breather do? just curious?

shawn

The cup isn't half full or half empty, it's just twice the size it needs to be!!!

 

[GeeAea]

It'll relieve more pressure and lower the velocity of the vapor. The catch can works in the same way ..high velocity oil vapor hits a larger chamber...loses it's velocity ..the oil drops out of suspension ...dadablabla. If you plug the breather you may get some detonation while "transitioning" the throttle (accelleration, lugging, etc.). 30,000 miles is kinda early to be having this much blow-by. So unless you've neglected it..or the rebuild was by Yahoo-engine-geeks I'd go with the cover as a problem. Did you have the same problem with the plastic cover? BTW- that aluminum valve cover you installed wouldn't happen to be a Clifford, would it? They allegedly have worthless baffling in them and unless they've changed something in the past year I'd look there first.

Do a search on blow-by ..you'll get plenty of threads on the topic.

GeeAea


Now that I've quit smoking my doctor informs me that I'll die in much better health!!!

 

[80cj]

i had the same problem with the junk plastic valve cover, plus it leaked. i ordered this valve cover from Krage. it looks like the standard in all the jeep catalogs for around $100. does someone make a breather with a check valve in it? i have read the articles about how to clean the baffles in your valve cover to eliminate this. that souldn't be an issue with brand new valve covers. am i the only one to ever have to deal with this?

shawn

The cup isn't half full or half empty, it's just twice the size it needs to be!!!

 

[GeeAea]

No...you are not the first one to get pregnant here...so to speak. Many have faced these issues.
Q: Has this done this for your entire ownership? That is, how long...did it just start happening one day recently or have you been dealing with it since you bought it?

Q: Was the rebuild that you mentioned (30K ago) total or just the head?

Regardless of the cause you've got to deal with this somehow. I'd get a mini K&N and run as long a hose as practical to it (hanging it somewhere on the firewall. If that fails I'd go to the catch can ...or try full manifold vacuum. Unless you're made of money ...or unless the motor is fouling plugs on a monthly basis ...or has NO power ..dadadablabla ..you just can't justify a overhaul.

Just for the fun of it unplug that T to the manifold and run a hose to the vent gromet and see if it remains drivable.

Do a search on blow-by (just the word blow should do it) there is a ton of posts on the topic.

GeeAea




Now that I've quit smoking my doctor informs me that I'll die in much better health!!!

 

[80cj]

it has not leaked the entire 2 years, but it has been doing it for about one year. in an odd coincidence, i changed the fuel filter last summer and this started. go figure?

about the rebuild. when i bought it, the owner said he had just put in a new motor. i didn't ask any more details. i do know it is an '80 cj, but the #'s on the block indicate it is a '77 and the head is an '81-'86 b/c it had plastic valve cover. so i know it was not just the head, but have never done a compression check, b/c the engine RUNS fine, its just these small details.

so why would a k&n be beter than what i have? does it have a valve in it? i know they breath great, but do you really think that is my problem? the oil is going OUT while air is going IN.

i don't understand what you were saying about unhooking the T.

thanks
shawn

The cup isn't half full or half empty, it's just twice the size it needs to be!!!

 

[GeeAea]

No two ways about it. If you've got oil going out you've got air going out. If you had sufficient windage into the crankcase/valve cover the oil would be drawn into the intake manifold instead of migrating out the vent. That is unless you've got a defective or poor baffling and the oil is physically ejected through the opening.

A K&N maybe no better than the one you have. It doesn't have a valve. The K&N is a bigger vent and the reason it works (sometimes) is that it works like a shop vac. You have a high velocity flow (the skinny suction hose or just the hole on the cover)..........you bring it into a large chamber (the can - in this case the breather) and it loses all it's velocity and drops the heavier contents of the flow (in the shop vac it's the dirt ..in the K&N it's the heavier oil droplets). If you hook this to a long hose and fasten it to the firewall you'll also disipate much of the force of the flow over the resistanc of the longer path. The oil droplets sink out of the stream and gravity sends them back into the cover.

What I meant by unhooking (I think I said unplugging) is that you can try and run the valve cover under manifold vacuum. You said that your PCV valve is "Tee'd" with one end plugged. Unplug it and run a hose with an appropriate fitting (perhaps another PCV valve) and plug it into the opening where your breather is now. That is, you'll have two hoses connected to your valve cover. The reason I say go with two hoses instead of just plugging the hole which the vent is in now is that you'll cut the velocity in half with two hoses. In this way the oil has no choice of where it goes. The problems that you may encounter, however, could be some detonation (pinging) when you are throttle transitioning (upshifting when you first put on the gas and when you're lugging the motor).

Since you say the thing runs great I'd just try and deal with the symptom instead of the cause(which I'm assuming is excessive blow-by).

GeeAea

Now that I've quit smoking my doctor informs me that I'll die in much better health!!!

 

[Guest]

This is one of those posts that one hopes is not the case with their motor, but have you done a compression test? My 304 broke the lands between the compression rings and the blowby was monsterous!! Showed up good on a compression test. You might have a cracked piston or a broken ring. I hope you don't, but it is a possibility.

81 CJ7 304/904/D300 scout 44's locked, full cage, 33"wildcats, warn HS9500i, bush bar from hell and diamondplate sides to cover gaping rust holes!! Coming soon OBA!!