Originally Posted By: BitterShard
Originally Posted By: omegaspeedy
... I don't think they tried enough RPM variations.
They varied between 6 tests until they found "The lower engine load, the more deposit formed"
Originally Posted By: omegaspeedy
There are different qualities and configurations of catch can. The length of the pipe from the tappet cover even makes a difference because oil can condense in the pipe and flow 'as a liquid' into the catch can...which is good. I've collected 1/2 a teaspoon of oil in 500km with mine. I think the test wasn't carried out long enough to conclusively prove that correctly collecting oil from the PCV system doesn't affect inlet valve carbon build up.
They tried a "catch can" that removed 100% of the PCV system oil. "By passing the positive crankcase ventilation lines" to outside the engine and ".. intake port was sealed by caps"
The only "oil from the PCV system" that would "affect the value carbon build up" would therefore have to come from outside the engine.
As far as running long enough, they pulled the valves and cylinders after each test and weighed them. The numbers they reported are in milligrams (0.000035 ounces).
Who cares if they found one condition in THEIR test that found the greatest condition of carbon formation! If you checked out the video I posted, the oil presented itself through RPM changes. Does their test cover all engine types and conditions?
Ok they bypassed the catch can entirely. Why did they bother installing a catch can if they were going to by pass it anyway? Did they connect a vacuum pump to evacuate the crankcase at the same inlet vacuum as the engine designer intended. If not I'd imagine there would have been a build up of blow by gases in the crank case which could have altered the out come. Seems counter productive and a bit dodgy if you ask me.
I'll keep my catch can thanks as I believe they help to prevent/reduce inlet valve carbon deposits. I can report that my car feels more responsive and I put it down to the fact I'm seeing the full 98 octane as the fuel is not getting diluted by the oily crud mixed with the inlet air.