How much of blow by is too much?
How much of blow by is too much?
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Discussion

vrooom

Original Poster:

3,763 posts

291 months

Friday 25th September 2009
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I replaced the headgasket on my missus 323f, due to oils in the chamber, had to check if it wasnt gasket leaking. Turn out a faulty PCV.

this engine has lot of blow by, but i dont know how much is ok, or bad.


How much of blow by is too much? How can i check?

dmitsi

3,583 posts

244 months

Tuesday 29th September 2009
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You could do a compression test on your cyls (you want them within 10% of factory spec), or you can hook up a pressure gauge to the dipstick, anything more than 1-2psi could indicate damaged rings, you want it negative.
I'm reckoning hooking up a blowby meter isn't an option. But if you do have access to one you hook it up to the crankcase vent on the breather, or the pcv valve fitting. You have to block the other vent so all blowby will pass through the flow meter, and run the engine up. You can select what units you want it displyed in, and as for what is too much, that depends on your engine.