how is advancing the timing better? old 350?

Question

I know pretty much about motor stuff, but this I stil dont get, on the combustion stroke the combustion pushes the pistion back down producing the power, so if the timing is advanced how can it work right? 75 chevy 350

Answer 1

Doug K's on the money. There are three types of timing going on.
#1.As Doug said Inital timing.
#2. As the distributer spins faster during acceleration spring restisted mechanical fly weights inside the distributer advances the timing even more.
#3. While the motor is at highway speed the rpm's drop, causing the mechanical advance try to retard the timing do to slower crankshaft speed. However, the third advance mechanism called a vacuum advance diapheagm advances the timing do th the intake manifold Vacuum.

Today's cars have an electrical advance mechanism is computer oriented. It does a better job of automatically understanding temperature, atmospheric pressure, engine temperature, fuel mixture and together with an anti- knock sensor. For street cars and trucks this is the best system.

For all out racing we still use distributors because we can tailor the mechanical, initial, and how fast it gets to the total mechanical advance. Racers have timing marks permanently machined across the face of the dampener. The marks indicate from 0 degrees to 40 degrees total advance. The racer knows precisely what total degrees they want to attain.
Racera set their timing completely oppicite as we do. They start the motor and rev it up above the all in mechanical timing built in the distributer. In other words they know at what rpm the distributor reaches total advance. They will need to spin the motor at an rpm above the mechanical set point total.

You'll see them use inductive timing lights with the engine at a very high rpm twist the distributer th find the total advance they want for max power and clamp it down. It's typical for a short stroke ( 3 - 3 3/8) small block Chevy run happily at 37-39 degrees total advance. Longer stroke (3.50 - 3. 750) lower rpm. motors run best at 30-34 degrees total advance.

Answer 2

Due to the actual speed of motion of the piston going up and down, the spark has to be advanced to ensure when the flame has ignited the entire mixture of combustible material in a pressurized state the piston is at the top and the connecting rod has moved over center and preparing to go down. The last little bit of rotation of the connecting rod does very little up and down motion to the piston so this also has a concern for advancing the timing. On Chevy 350s there is also a vacuum advance that is on at idle which increases the advance on the base timing adjustment right away. As motor speed increases, there is a need to continue to advance timing as the flame needs time to burn which is why there is increased advance. In higher compression ratios there is a need to advance the timing right away as compressed gas takes more time to ignite completely so there is another need for more advance. Get the picture. What is a good rule of thumb to use with these motors is to give them all the base advance timing they can handle without pinging or backfiring and set it there. You can also play with the weights and vacuum advance to bring it in faster or slower depending on your motor's needs. Good luck.

Answer 3

Sorry you got a spammer there.

In the first stroke (piston moving down), there is intake.
Second stroke (piston moving up), compression.
Third stroke (down), power.
Fourth stroke (up), exhaust.

Spark (or ignition) happens at the very end of compression, where the fuel/air mixture is most volatile. If the spark does not happen before top dead center or TDC (advanced timing) then the piston would already be on its way down. The piston moves down because of the ignition of gases. In a perfect world, the ideal place to ignite the mixture would be at TDC where the piston has stopped upward momentum and is ready to begin it's downward stroke. Unfortunately, we do not live in a perfect world, and it takes TIME for the flame front to move across the piston face. Granted this is a small fraction of a second, but the piston is at TDC for less than that. This is why the timing is advanced a certain number of degrees before TDC or BTDC.

I hope I have helped you understand.

Answer 4

In a nutshell, advancing the timing does not always help. It can promote spark knock or pinging, which can lead to permanent engine damage if it gets too bad. There are many different factors involved with engine performance, like fuel quality, air temp, engine temp, etc. A normal street driven engine can only tolerate so much timing advance before it becomes destructive, but a few degrees usually helps the engine accelerate a little faster.

Answer 5

Do you nevertheless have the previous motor? are you able to verify the balancer? they're in many situations all the comparable with the pointer on precise around 2. (status in front of engine). i'm guessing that via fact that's in a motor domicile and stressful to work out, you could actual have placed the timing gentle on the incorrect twine.

Answer 6

generally, advancing the timing will give you more power but less gas mileage. or, if you want to get more gas mileage you can retard the timing but at the cost of some power