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Discussion Starter #1
This is branched off from my other problem thread, just wanted an anwser on why or what makes the dip stick blow out... what can cause it...

Blow by is the only one i know... but it has 3percent leakage.....

help
 

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superclarkey said:
but why does it cause pressure?? or is this normal??
No its not normal. Id get a clyinder compression test done if i was you. It could be just blocked breathers or you may have a problem with piston rings letting blow by gasses past and causing pressure in the crankcase.
 

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Discussion Starter #5
11 bar of pressure across all cylinders between 3 and 5 percent leakage....

This is why i'm confused ;)

HELP
 

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superclarkey said:
but why does it cause pressure?? or is this normal??

you have large masses of metal pumping up and down inside an engine so its not only blow by that causes pressure.

I had real problem with my bike and excess crankcase pressure in the end i added an extra breather and it was fine , the problem was caused because i had over bored it so much the stock breathers couldnt cope
 

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Richf said:
you have large masses of metal pumping up and down inside an engine so its not only blow by that causes pressure.

I had real problem with my bike and excess crankcase pressure in the end i added an extra breather and it was fine , the problem was caused because i had over bored it so much the stock breathers couldnt cope
This is very true but a stock engine should not blow out the dipstick unless there is a problem. The stock breather system would be able to cope unless the breathers were blocked or there were too much blow by gasses pressurising the crankcase. A long while back i had a fiesta xr2i that blew the oil cap off when it reached 3500 rpm, turned out to be piston rings/bore wear.
 

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Discussion Starter #10
Ah, well its got cams fitted apart from that it was a stock build with Tomei 1.2 mm headgasket

I just can't understand this. makes no sence
 

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Spearmint said:
So to increase the capacity of the breathing system, is it just a case of a couple of extra holes in the top of the cam covers?
for me the extra vents were added to the cases but yes same principle

BUT

Its correct the stock system should easily be able to cope

You could always fit a vac pump of course;).
 

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now i know i know nothing but............


the 210MPH sierra, it uses a catch tank that brethes to atmo and then spits the oil collected down the dipstick hole

big reduction in crankcase pressure for almost nothing, vent dipstick to catch tank that has a one way valve and when pressure drops the oil will sink back into the sump, whenever it needs to pressure will just come out

obviously it has to be gravity feed return but im sure you can work out how this can be done

EDIT PICS
T.F.S.© said:


two dipsticks...two catch tanks...


one way valve from B+Q performance tuning section..
 
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