What does BTDC mean timing?

What does BTDC mean timing?

before top dead center
“Timing advance” refers to the number of degrees before top dead center (BTDC) that the spark will ignite the air-fuel mixture in the combustion chamber at the end of the compression stroke.

How do you set the timing on 10 degrees BTDC?

Procedure

1. Rotate the engine to TDC on the Compression Stroke of the #1 cylinder.
2. Install the Degree Wheel on the crankshaft and set it to zero.
3. Turn the crank backwards until the degree wheel reads 10 degrees BTDC.
4. Align the distributor rotor with the cap location for the #1 spark plug wire.

What is normal timing advance?

The TA value is normally between 0 and 63, with each step representing an advance of one bit period (approximately 3.69 microseconds).

What happens at the 10 degree BTDC on the graph?

At about 10 degrees BTDC on the graph (-10 on the X-axis), the igniting of the air-fuel mix is finished and the air-fuel mix starts to increase cylinder pressure from the expanding force of the combustion event. Cylinder pressure rises, as the burning air-fuel mix expands and pushes down on the piston top.

What should the ignition timing be on a Nissan?

You can clamp your timing light to this. Much easier than pulling the coil, adding and adding a wire. To adjust, turn the CAS. Timing should be 15* BTC. Looking at the marks on the crank pulley, from left to right (passanger side to driver side) is 5* AFTER TDC, 0, 5, 10, 15, 20* BTC. So you want to line it up with the second from right mark.

What should the ignition timing be at idle?

When I’m tuning with Nistune or Live tune the timing at idle shows 10 degrees (even on a stock tune 8 port Jap head and ECU). If set at 15 then you will be 5 degrees advanced through out the whole timming map. Not really ideal when you are on the edge of the engines limits.

When does the cylinder pressure rise after TDC?

Cylinder pressure rises, as the burning air-fuel mix expands and pushes down on the piston top. The greatest force or highest cylinder pressure occurs at 20-25 degrees After TDC (ATDC) [+20-25 degrees on the x-axis].