My crank shaft is rotating twise the crank shaft. HOW MY 1342 FIRING WILL OCCURE?, I can spare only 30 digree for charge and spark plug contact. THERE ARE ONLY 2+2 CYLINDER. 180 DIGREE APPART KINDLY REPLY...
Your crankshaft turns 2x times the camshaft. Put it this way as # 1 cylinder reaches TDC (top dead center) of the firing/compression stroke, and this will be after a (8 degs BTDC) spark to ignite the air/fuel mix, the # 3 cyl. will be at BDC of the intake stroke and as #1 begins its power down stroke, (during explosion of air/fuel mix), #3 begins its compression up stroke, the #4 cyl. will be coming down with #1 cyl. but #4 will be in the beginning of its intake down stroke, and #2 cyl. will be coming up with #3 but #2will be in its BDC of the exhaust stroke. Which has just fired previously to #1. 1342134213421342 etc.
Now the cam turns to open / close the valves;
In the outline above, #1 cyl. valves will both be closed. #3 cyl. will have the intake starting to close at this point. #4 cyl. will just be starting to open its intake valve, and #2 will be starting to open its exhaust valve. Is all this clear as mud? So as the crank makes one full rotation (in a 4cyl. engine) only the firing of one cylinder has happened.and at every rotation one cyl. will fire. So #1 at TDC then one full rotation, #1 back at TDC, but this TDC is half of its 4 cycles, (1)Intake, (2)compression, (3)power, (4)exhaust. this 1234 refers to the 4 cycles of the rotation not firing order.
Oct 31, 2010 |
2008 Volkswagen Jetta