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Author Topic:   oil out of the breathers
posted June 11, 2003 12:34 PM
I am having oil come out of my breathers and can't figure out why. Heres what I have simple 355 12.5 compression double hump heads total seal gapless rings (2nd ring) on alcohol. Simple motor that runs great. Compression is fine motor is on 5 races old, valve covers are indexed correctly (breathers. Oil return passages are open and have even been deburred/radiused. Only thing I can come up with is simple blow by on ring but compression is fine. ANY THOUGHTS,

jhon hollomon
posted June 11, 2003 12:51 PM
Do you have the breathers on the passenger side of the motor? That would make oil come out sometimes.

posted June 11, 2003 12:54 PM
Simple cranking compression is one thing, but ring seal (or lack of it) causes blow-by and pressurizes the crankcase, pushing oil out the breathers.
Perhaps could you have "washed down" the cyl's at some point with alky thereby wiping out ring seal?
Since you have gapless style rings, I wouldn't think it could be just a simple case of ring gaps lining up and allowing blowby.
Yeah, the more I think about it, it's ring seal. Try running a leakdown test on the motor and see if one or more cyl's is not sealing well.

Hope that helps...


posted June 11, 2003 02:05 PM
how much oil are we talking about, a teaspoon, pint, quart?

We had one once that at higher rpms would pump oil out the breather. Turned out to be a cracked block and 1 cylinder didnt seal and then the crankcase pressure would not let oil back down out of the head. I agree with KP if you are getting a lot of oil then you prob have 1 or more cylinders not sealing.. do a leakdown and see what you find.

rico 08
posted June 11, 2003 05:38 PM
You can try some steel wool in the breather tube or a baffle in the valvecover.

DMA Racing
posted June 11, 2003 07:50 PM
my little girl puts a pair of white socks on them every week.......i could have brought a new tire for what the socks have cost lol

posted June 11, 2003 08:55 PM
Hey I bought a pair of the sweat bands like tennis players use around their wrists...wash them when I clean the air filter and slip these terry cloth "outerwears" back over the valve cover breathers and I'm weddy to wok!
I have had both shielded and unshielded breathers...the sheilded ones haven't given me any grief like the open ones did.

posted June 11, 2003 10:51 PM
I had the same problem last year. I used
to just use a rag and never had a problem
then I got the real ones and they leaked.
I put the metal pads used for washing
dishes down the tubes for baffles and it worked good.

posted June 11, 2003 11:50 PM
I can think of 1 or 2 things that have caused this to me in the past....First was allky in the oil or alot of condensation that would collect upo there and drip out... the other was the cheap oil pan i was running without windage or scraper and it would froth the oil making it more misty along to come out the breathers....i have got a good carb now and a good pan ....allmost forgot i also put stud girdles on wich helps block the oil from getting up there.......not saying thats your problem just that those are things i have done to help it..... BTW i still have some nasty old socks on my breathers....i used black ones so they would stick out so bad!

GO 24
posted June 12, 2003 11:50 AM
Our engines have always done it and we use the gapless rings also. Were only talking about a very small amount of oil bleeding through the filter element which is more of a pain than a concern, our builder told us to tear off a chunk of foam mudplug and stuff it in the breathers and then forget about it.

posted June 12, 2003 12:52 PM
i put fuel cell foam in perfect.


posted June 12, 2003 03:01 PM
I definetly wouldnt stick steel wool in their.. Just think of all the tiny steel slivers that break off and get into your engine. The plastic dish scrubbers would prob be ok as long as they didnt fall apart or have pieces break off of them.

posted June 12, 2003 06:35 PM
I've always extended mine out to the engine hoop with hoses.This raises them and keeps oil from blowing out.

posted June 12, 2003 11:35 PM
Thanks for all the responses. I will leak test tonight. I have a good pan clean my beathers about every 3 weeks. I will step up the fequency. I tryed the foam in the tubes but I am concerned the foam will break down and cause other issues. I the leak down test shows to be good I am going to try installing soft plugs int the tubes with say 3 holes in them. This should allow the engine to breath yet slow any oil down. As far as how much oil is coming out. Hard to tell. If I was to estimate I would say 1/2 pint to a pint. Just enough to make a mess.
Thanks well provide feedback after leak test.

posted June 13, 2003 10:39 AM
were do u put the steel wool at?????????? in the breather filter ot in the breather tube????????

posted June 15, 2003 07:25 PM
I wouldn't put anything in them breathers that could come apart.I had the same problem which turned out being oil shooting right in the tubes from the rockers so I made baffles so it couldn't get in the tubes last year and fixed it.This year I'm running oil deflecters and I might get about 5 drops of oil coming out after running all night.

posted June 15, 2003 11:33 PM
I was wonderin cuz i am runnin a hyd. motor since i am on a very very tight budget.

posted June 16, 2003 09:03 AM
I dont know where these guys are putting the steel wool but I would not put it anwhere on any engine. Think about it every time you handle steel wool you get that fine powder and a few little pieces of the wool on your hands. Do you really want all of this in your engine acting like sandpaper and grinding away at your bearings, crank, etc.. I would try wrapping rags around the breathers, maybe making some sort of baffle for the tubes, or even the foam or nylon scrubber idea.

posted June 16, 2003 12:46 PM
i haven't put anything in my breathers yet. the breather tubes still have baffels on them but i'm gettin oil up in the breather and out of them.

posted June 17, 2003 06:44 AM

I was having the same problem, get 1 1/2 pipe, cut an oval hole in it, and weld a y coming off of that. The straight part you want to fit between the breathers with about 1/2 gap or so on each side between breathers. Now take a radiator hose, cut two 90 degree radius's and connect the to straight ends to the breather towers. The Y end gets another hose and run either up to the front hoop or anywhere that works for your car away from the motor. Mine actually runs back down on firewall/front driver side fender. I then have a rag zip tied on the end. No more oil on motor. In fact there is very little oil residue even on the rag. The hose I have connected to the Y section is just an old radiator hose also (flex type).

Hope you can understand all this blah blah blah.

[This message has been edited by sjakes8 (edited June 17, 2003).]

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