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'78 Cav Coupe - 1900S Engine, Oil In Top Breather Hose.


Rob36
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Hi Guys, Id appreciate picking your brains! Took the cav out for a longish run the other week, but when I got back, she was blowing oil from the breather hose at the top of the rocker cover into the airbox. Innitially I thought the rocker gasket was leaking, so changed that - that was when I realised oil was in the air pan - coming from the aformentioned breather. The car refuses to idle, itll just cut out.

There was oil in the top of the carb, so I blitzed a bit of carb cleaner in there to clean it up, but it's still not idling.

As for the breather, for now Ive added a bit of gauze in the breather outlet at the top of the rocker cover, but cant help thinking this may be attempting to treat the symptom rather than the cause.

I was thinking of checking other breathers for blockages - thinking this might be forcing oil out of the top coz its blocked elsewhere. Other than that... not sure!

Any thoughts?

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Rob36

Do exactly as you thought and check the other breather pipes first. Clean any gauze filters out with white spirit (soak in it if needs be). If none of that changes anything it could be that your getting blow-by on the piston rings.

To check this take the oil filler cap off and check if air blows out of the hole (i usually use a bit of paper or thin card across it). If it is blowing check the compression, that'll tell you if the engines ok or not. Some engines do blow a bit and are fine, just fit an oil breather/catch tank in the breather line.

I used to run a 2.8 V6 ford engine in an oval racer (yeah i know i might get some stick for saying that!!) and that used to blow oil everywhere if i filled it to the max mark, but it always blew the oil down to 1/3 way between max and min every time. I marked the dipstick to check it!!! Some motors are just different.

HTH

Chris

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Thanks for the advice guys - Ill check it out and hopefully its nothing major. Lampchop! Fellow oval racer! I too race! Light contact Bangers. Not old Vauxhalls though lol. Honda Civics, Rover 216 and the like.

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ok cheers. I did notice that it was a bit gunky under there when I changed the gasket. The underside of the cover had a raised plate underneath with open sides leading to the breathers at the top - I take it the gause is under there?

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definately a good place to start is cleaning the gauze inside the rocker cover. you need to bend back the tabs to get it out.a bit awkward.but possible. the idea is that the gauze collects any oil & lets it drain back into the engine & the breather pipe has gas / fumes going throu bit only.

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Yeah I thought as much regarding the Idle. Thats now sorted, a good dose of carb cleaner seems to have done the trick. I shall get the rocker cover off as soon as I get a mo and de-sludge it. Thanks for the input guys!

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