TWO THINGS GOING ON HERE
1) THE PCV SYSTEM (POSITIVE CRANKCASE VENTILATION)
2) COMBUSTION BLOW BY FROM THE PISTONS (CYLINDER AND RING WEAR)
THE PCV SYSTEM SORTA SUCKS OUT THE WATER VAPORS AND HARMFUL GASES, WHICH MIGHT CORRODE PARTS, THAT BUILD UP IN HOLLOW INTERNAL ENGINE SPACES.
THESE GASES NORMALLY GET IN THERE IN VERY SMALL AMOUNTS BECAUSE THE PISTON RINGS CANNOT SEAL OFF THE COMBUSTION CHAMBERS 100% (THE CORRECT RING GAP, RING PLACEMENT, AND GOOD RING SEATING WILL MINIMIZE THE BLOW BY AND INCREASE COMPRESSION).
MEGA CYLINDER WEAR, BROKEN AND WORN RINGS, CARBON BUILD UP IN AND ON PARTS SORTA ALL WORK TOWARD COMPROMISING THE COMBUSTION CHAMBER SEAL
EVENTUALLY, OVER TIME, THE BLOW BY WINS (IF YOU PULL OFF THE FRESH AIR INTAKE HOSE ON THE VALVE COVER SMOKE WILL PUFF OUT OF THE GROMMET WHILE THE ENGINE RUNS)
TO INSURE THE PCV IS WORKING RIGHT AND IS DOING ALL IT SHOULD (IF IT'S NOT TOO LATE) THIS IS WHAT SHOULD BE HAPPENING
1) THERE IS NO CARBON OR SLUDGE BUILD UP IN THE ENGINE/ INTAKE MANIFOLD PASSAGES WHICH MIGHT RESTRICT VACUUM FLOW
2) USE THE CORRECT PCV VALVE AND HOSES ARE REPLACED ON SCHEDULE OR WHEN NEEDED
3) THE SYSTEM IS ACTUALLY SEALED WITH GOOD GASKETS (PAN/ VALVE COVER) AND GROMMETS
3) THE FRESH AIR END IS AN OPEN FITTING WHICH DRAWS FRESH AIR FROM (NORMALLY) THE AIR CLEANER
USING A 2ND PCV VALVE, IN THE FRESH AIR END IS TOTALLY UNACCEPTABLE. PEOPLE DO THIS BECAUSE IT "FITS" IN THE GROMMET NICELY. WHAT THIS REALLY DOES IS 100% RESTRICT FLOW. THE PCV VALVE IS A "CHECK VALVE" WHEN YOU SUCK BACKWARDS THRU IT. LOSE IT! WE WANT 100% OPEN FITTINGS ON THE FRESH AIR END
WHEN THINGS ARE WORKIN' GOOD, YOU CAN POP THE FRESH AIR HOSE OUT OF IT'S GROMMET ON THE VALVE COVER
PLACE YOUR THUMB OVER THE HOLE
THE PCV SYSTEM WILL BEGIN TO SUCK A VACUUM INTO THE HOLLOW ENGINE, NOW THE ENGINE WILL SORTA NOT RUN AS SMOOTH AS IT DID (YOU ARE DEPRIVING IT OF AIR IT NEEDS FOR COMBUSTION!)
IF YOU SNATCH YOUR THUMB OFF, YOUR HEAR A BIG GULP FOR AIR (LIKE SUCKING THE AIR OUT OF A COKE BOTTLE, THEN RELEASING IT)
THE ENGINE WILL RUN NORMAL AGAIN
X) IF YOU REMOVE THE FRESH AIR HOSE, AND IT SPITS SMOKE RINGS AT YOU, YOU FEEL NO SUCTION (AND YOU HAVE DONE ALL YOU COULD DO TO FIX IT) IT'S PROBABLY GETTING CLOSE TO REBUILD TIME!
I REBUILT MY 1977 AMC 258 6 CYLINDER JEEP ENGINE IN 1995, IT IS MY DAILY DRIVER, I HAVE WELL OVER 150,000 MILES ON IT. IT'LL PASS THE THUMB TEST EVERY TIME!
THE MEDIC
Images (Click to make bigger)
Sunday, May 17th, 2015 AT 1:46 PM