Reversion is simply the intake and exhaust gases momentarily flowing backwards during the overlap phase of the camshaft at low cycling rates. Overlap means just what the word implies. The intake event overlaps the exhaust event and the exhaust event overlaps the intake event. The overlap event starts with the piston on the exhaust stroke. As the piston is pushing out the last of the exhaust gases and about 30 or so degrees before the piston reaches top dead center, the intake valve begins to open. At low cycling rates the intake charge and the exiting exhaust pulse have not yet created any momentum. Thus, the piston pushes some of the spent exhaust gas into the intake manifold. That is why engines with big camshafts have such a radical sounding idle. The exhaust pulses shoot up into the intake manifold, causing a major disturbance. The cylinders receive an uneven mixture of air, fuel, and spent exhaust gas
the anti reversion dam in the picture below is what bdomit is talking about, but i am not sure if the manifold is bigger than the D shaped port. if it is, thats ok. if it isnt, then no it wouldnt be good i dont think
the anti reversion dam in the picture below is what bdomit is talking about, but i am not sure if the manifold is bigger than the D shaped port. if it is, thats ok. if it isnt, then no it wouldnt be good i dont think
