If a piston is at top dead center on the compression stroke, both the intake and exhaust valves should be closed. When at top dead center on the exhaust stroke, the exhaust valve should be open.

The advance timing mark is used to set the timing to the factory setting, such as 40`. Best is to use a dial back timing light to check or set timing. Remove spark plugs. Rear wheel off the ground, shift to 2nd gear, rotate wheel until it clicks, repeat until you get to top gear.

You want the points follower(the part of the points that rides on the cam) to be on the center of the rear cylinder lobe (the wide one). Loosen the screw securing the points to the point plate. Use a screwdriver to adjust the point gap (you will see the slot in the points plate and the case behind it).

To find the Top Dead Center (TDC) on a diesel engine, virtually all diesels will have a mark on the front pulley and another mark cast into the front housing, just line the two up.

Once the top dead center timing mark is lined up with the marker on the engine, the motor should now be at top dead center. To verify, shine the flashlight down into the spark plug hole. You should be able to see the top of the piston clearly near the top of the cylinder.

You can turn the crankshaft back and forth (by hand ) while observing motion of the ( screwdriver; coat hanger or straw ) to get a better idea of the location of the piston. When you see it has reached its highest point of travel, it is at (TDC).

It’s up to you. Both valves should be closed if it’s TDC at the end of the compression stroke. If it’s TDC at the end of the exhaust stroke, you should be in the valve overlap zone, with the intake valve partially open and on its way to opening fully, and the exhaust valve partially open on its way to closing.

This is measured in degrees of rotation. Most engines set ignition timing somewhere between zero and 20 degrees before top dead center.

Piston Position can be determined from the crank angle from Top Dead Center, knowing the Stroke of the engine, Length of the Connecting Rod and the angle of the Crank. As the Crank Shaft rotates a certain degree, the Piston moves a certain distance from Top Dead Center.

If you are curious, you can easily convert the crankshaft angle into a time: for a given RPM of say 15’000 1/min the time required for one revolution is 1/15’000 minutes which is 1/250 seconds.

‘Ineffective Crank Angle’ is an arc of travel at both TDC and BDC where there is very little piston movement. 18 The Operating Cycle The cycle is happening in every cylinder, in all 4 stroke engines, no matter how many cylinders there are.

Filters. (motors) The angle of rotation of a crankshaft measured from the position in which the piston is at its highest point known as top dead center (TDC).

K = distance between the center bearing and the crankshaft, in, and. θ = crank angle, rad. where: dθ/dt = instantaneous angular velocity of the crank, 1/s, and.

A crank is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice versa.