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post #1 of (permalink) Old 03-25-2001, 04:11 AM
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Blow by ?

My 83 CJ7 258 I6 has been pulling oil through the breather line from the carb to the rear of the valve cover. I'm pretty sure that it is the infamous blow by, but don't want to face facts. The engine has 86000 original miles on it and read on the board that blow by is common after 80K. So, is there anything else that could be cause this? ( I replaced the PCV valve 2x in 2 months hoping it was a bad) it wasn't.

Is there any engine additives that you guys can recommend that might help me out for the time being and if so the best place to get them?

Thanks for the help

BentMetal

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post #2 of (permalink) Old 03-25-2001, 03:58 PM
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Re: Blow by ?

your piston rings are wearing out.. you need new ones..
when they start wearing out gases get by them.. and down into the crank case (oil pan).. that gas builds the pressure up down there.. so the oil.. as it is pumped up to the head.. will not drain down into the block like it should (since it has a higher air pressure in it).. so it takes the route of lease resistance.. ie. your open line to the air filter..
DO NOT PLUG THIS LINE!! or your engine will not be able to blow of the pressure.. and you will blow more seals in the engine.. and start leaking oil everywhere.. for a quick fix.. you can take that hose and run it into a container that is secured inside the compartment.. i used a gatorade bottle.. when it got full.. i dumped it.. i ran my jeep like this for about a year..
it wont hurt it.. like i said.. its just your piston rings wearing out.. they do that..
you can check this for sure with a compression test.. get one from autozone.. they loan them out.. you screw it into the head.. where the spark plug goes.. disconnect the coil from the distributor.. and turn the engine over.. you just want to spin it.. not start it.. check guage.. should be about 150 psi.. do all cylinders.. then to retest the low cylinders.. squirt some oil into the spark plug hole.. and retest it.. if the pressure jumps up.. to somewhat normal.. then the rings are bad..

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post #3 of (permalink) Old 03-25-2001, 06:00 PM
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Re: Blow by ?

Before PVC valves were required, the oil just drained onto the ground.

Good Luck!
Kriss

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post #4 of (permalink) Old 03-25-2001, 06:00 PM
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Re: Blow by ?

Just don't do like jeepgod and reuse the oil.[img]/wwwthreads_images/icons/wink.gif[/img]


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post #5 of (permalink) Old 03-25-2001, 06:12 PM
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Re: Blow by ?

"Restore" engine additive help me greatly on two old 258. It reduced blowby. For $6 ,try it. Otherwise, like the guy say... new rings.


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post #6 of (permalink) Old 03-25-2001, 06:50 PM
 
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Re: Blow by ?

Hey guys I have a really recently rebuilt engine..and for some reason the back hole in the valve cover isn't plugged and it doesnt have a line coming through it.I don't know how to put a hose on a hole
What to do what to do?I put some tape over it so I wouldn't get stuff in the oil but I don't want to mess up the engine!

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post #7 of (permalink) Old 03-25-2001, 07:41 PM
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Re: Blow by ?

now joey.. im not sure im the one to enlighten you on putting your hose into a hole.. [img]/wwwthreads_images/icons/laugh.gif[/img]..
but for the valve cover.. most have a rubber grommet in the hole.. like a rubber washer.. that grows around the lip of the hole.. and you just PUSH in the hose... but make sure you hit the hole.. it could be damaging if you dont... [img]/wwwthreads_images/icons/laugh.gif[/img]..
if anything get a valve cover filter.. at the auto parts joint.. make sure it will fit into the hole.. they are about 5-10 bucks.. but do not plug up the hole.. more than likely you will blow the rear main seal..

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post #8 of (permalink) Old 03-25-2001, 07:50 PM
 
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Re: Blow by ?

Hahaha!I'm sorry I know that kinda stuff doesn't belong here.Thanks for telling me that..I never knew it [img]/wwwthreads_images/icons/smile.gif[/img]
I'd go do it in a minute cept for the fact I dont have any hose.
Thanks
Joey

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post #9 of (permalink) Old 03-25-2001, 09:36 PM
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Re: Blow by ?

Thanks for the replies. I hate facing the fact that it is the rings because I'm not financially up for a rebuild, but have known it all along. I'll try the engine restore to get me through a few more months and also getting a container set up to catch the run off. No,I won't reuse the oil

So, even though I don't have the duckets at the moment to do a rebuild, how hard will it be or should I just get a rebuilt motor from one of the auto parts places?


post #10 of (permalink) Old 03-25-2001, 11:05 PM
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Re: Blow by ?

Had the same problem on my 84 258...ended up just saving up for a month and getting a rebuilt kit for the engine for about $200 that had the rings and all bearings and some other goodies. Works great now with no blow by...

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