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smoke from under rocker cover

Posted: Mon Oct 11, 2010 4:42 am
by karol
hi
yesterday after a while of running the engine, i opened the oil filler cup and there was bit of smoke coming from the inside. then i disconnected the rubber hose, that goes from the rocker cover into the air filter reved the engine and there was again smoke coming out. more as it reved higher. what does it mean? is something horrible about happen to my engine? its patrol with tb42 carby
cheers

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 6:18 am
by MrGrim
it could be all normal as a little blow by ..
depending on the ks the motor has done
this aslo would be normal on an old engine " worn rings "
to settle your nerves just do a compresion test if thats all good
then forget about it

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 7:06 am
by BundyRumandCoke
As said, some smoke can be normal. The job of the rubber hose, the PCV (Positive Crankcase Ventilation) system is to remove that smoke, and associated gasses, and pass them into the inlet manifold, where they are burnt in the normal combustion process. Worn rings or valve stem seals could be the culprit. How many Ks on the motor?

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 9:54 am
by 351ciofgrunt
It's normal, don't worry about it

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 5:04 pm
by karol
the engine has done 300 000 km however I'm not sure how genuine they are. can i eventually somehow block the whole smoke recirculation off?

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 5:10 pm
by dogbreath_48
karol wrote:the engine has done 300 000 km however I'm not sure how genuine they are. can i eventually somehow block the whole smoke recirculation off?
No, but you could run a catch can to catch some of the smoke (oil vapor) before it gets into the intake. But unless it's excessive and causing other problems there's no reason to.

Blocking the rocker cover breather off is a big no-no and having it vent into the atmosphere is a legal no-no.

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 5:32 pm
by karol
apart from not being exactly legal, would it work if i plug those two hoses and put two of those small tiny supercheap auto air-filters on the rockercover? im just worried that all that smoke can not be good for the carby

Re: smoke from under rocker cover

Posted: Mon Oct 11, 2010 5:41 pm
by MrGrim
karol wrote:apart from not being exactly legal, would it work if i plug those two hoses and put two of those small tiny supercheap auto air-filters on the rockercover? im just worried that all that smoke can not be good for the carby
its no problem at all for it unless its making the throut of the carb realy oily then fix with a catch can ..a breather as you sudjested will also suck water if you cross a creek ect with the sudden cold change

Re: smoke from under rocker cover

Posted: Wed Oct 13, 2010 8:23 pm
by McLarryBob
A bit of smoke from the engine is normal and that is exacly what the PCV is there to get rid of.
You definatly don't want to block off the PCV because all those gasses have to go somewhere. If you do block it off the gasses will build up in the engine and will have to escape somewhere and that somewhere will be your oldest/weakest oil seals. And you don't want that.

http://www.youtube.com/watch?v=8-ymU7ET ... re=related" onclick="window.open(this.href);return false; This is a cool vid showing what happens in the engine and how much smoke/oil vapor can be produced