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crankcase pressure - how to measure/detect
Posted: February 5th, 2008, 12:20 pm
by smckeown
I undersdtand this is common on worn engines, but i've already read it can happen on newly built units too.
So i'd like to read more with regards tothe following:
How can it happen on new builds ?
How do you detect it
How do you resolve it
thank you
sean
Re: crankcase pressure - how to measure/detect
Posted: February 5th, 2008, 9:52 pm
by SirYun
How can it happen on new builds ?
there are quite a lot of reasons that can be thought off:
-unseated piston rings.just needs more miles or,
improper bore diameter/taper.. or any variant thereoff
wrong hone finish..or no honing/ball hone after fresh rings.
improperly gapped/clocked rings.
i'm shure there are dozens of reasons more.
How do you detect it.
-usualy a disconnected carter vent will show the blowby/positive pressure. i have had one engine with fully broken and trashed ring on one piston with caused large amounts
How do you resolve it.
-depends on the cause.
i recently did a head for engine ( BL.A series like about 99% of what i am involved with) that smoked terribly after startup and many miles thereafter. even though it had viton seals fitted and had a reasonable amount of care at assembly time. switching to a much more basic oil (20w50) cured about all in this case. those engines like thick oldskool oil.. and very frequent changes.