Advancing Timing??? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

luey02 · 03-10-2002, 04:14 PM

I just tried to advance my timing this afternoon (yeah nismo14) but I turned the distributor as far over as possible and I hear no knocking??  It drives fine but just wonderin why people say to stop turning when knockin???  

thanks
K lu

White240sx · 03-10-2002, 04:23 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (luey02 @ Mar. 08 2002,6:14)</td></tr><tr><td id="QUOTE">It drives fine but just wonderin why people say to stop turning when knockin??? </td></tr></table><span id='postcolor'>
Detonation or "knocking" occurs when the air/fuel mixture combusts before its prescribed interval. By advancing the time timing, you cause the spark to light sooner, and if it sparks too soon it could combust as the piston is rising instead of starting to go back down. Not only does it waste the power stroke, it puts a lot of strain on the piston/rod/crank assembly.

v8killer · 03-10-2002, 06:19 PM

It also depends on what type of fuel you run. If you use very high octane fuel, you won't have to worry about hearing a "knock". Knock occurs when you run weak gas and set your advance too far. The piston travels up, the spark ignites the fuel prematurely, then the piston tries to go back down. Welp, the crank has something else to say about that, and the piston has nowhere to go. THEN, the piston vibrates FAST and HARD inside the cylinder back and forth instead of up and down, which is why you hear a "knocking" sound. EXTREMELY DANGEROUS. Now, if you run better fuel in your ride, then the fuel is more stable, resisting to ignite prematurely. (Obviously, to only so much advancement) That way, you won't hear that knocking sound, unless of course you could advance your timing to something astronomical, and them it WOULD knock, or just quit. LOL!

Long and drawnout- but I hope this helps....

PeaceOut!

03-10-2002, 04:14 PM	#1
luey02 Zilvia Junkie Join Date: Jan 2002 Posts: 519 Trader Rating: (0) Feedback Score: 0 reviews	I just tried to advance my timing this afternoon (yeah nismo14) but I turned the distributor as far over as possible and I hear no knocking??  It drives fine but just wonderin why people say to stop turning when knockin???   thanks K lu __________________ K. Lu

03-10-2002, 04:23 PM	#2
White240sx Zilvia Member Join Date: Nov 2001 Posts: 219 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (luey02 @ Mar. 08 2002,6:14)</td></tr><tr><td id="QUOTE">It drives fine but just wonderin why people say to stop turning when knockin??? </td></tr></table><span id='postcolor'> Detonation or "knocking" occurs when the air/fuel mixture combusts before its prescribed interval. By advancing the time timing, you cause the spark to light sooner, and if it sparks too soon it could combust as the piston is rising instead of starting to go back down. Not only does it waste the power stroke, it puts a lot of strain on the piston/rod/crank assembly. __________________ -Mason

03-10-2002, 06:19 PM	#3
v8killer Zilvia Member Join Date: Oct 2001 Posts: 150 Trader Rating: (0) Feedback Score: 0 reviews	It also depends on what type of fuel you run. If you use very high octane fuel, you won't have to worry about hearing a "knock". Knock occurs when you run weak gas and set your advance too far. The piston travels up, the spark ignites the fuel prematurely, then the piston tries to go back down. Welp, the crank has something else to say about that, and the piston has nowhere to go. THEN, the piston vibrates FAST and HARD inside the cylinder back and forth instead of up and down, which is why you hear a "knocking" sound. EXTREMELY DANGEROUS. Now, if you run better fuel in your ride, then the fuel is more stable, resisting to ignite prematurely. (Obviously, to only so much advancement) That way, you won't hear that knocking sound, unless of course you could advance your timing to something astronomical, and them it WOULD knock, or just quit. LOL! Long and drawnout- but I hope this helps.... PeaceOut! __________________ 91 SE Coupe wit' all the fixins' http://www.roadtoadspeedshops.com