Advanced Timing

[SuperStock96]

I see a lot of people who have advanced their timing from 14 to 17 degrees. How is this done? Don't you need to change the timing when you change camshafts? I am basically looking for a fairly simple explanation of how this works.

[Nahkapohjola]

Originally Posted by SuperStock96

... simple explanation of how this works.

Timing: Spark relationship to Piston position.

Freeze frame -picture at 15degrees Before Top Dead Center BTDC:
- Piston has almost been stopped in upmost position.
- Piston is still moving up (very little), maybe 1mm.
- Piston is on its 'last leg' of compressing the air/fuel -mixture.
- Next fraction of second, Piston will start its downwards travel 'kick'.
- Crankshaft is rotating with high speed.

I is beneficious to ignite the mixture just now, otherwise we are late = the piston has bee travelling down as explosion waves start creating the down pushing power.

Ignite mechanism: via camshaft located sensor information. When this sensor trips, ECU initiates spark. Changing this sensor trip timing changes spark timing.

The engine gives more power, the earlier the spark is. Why not adjust 40 degrees BTDC? If ign comes too early, the piston kicks down and forces cranckshaft rotation diretion change. Then we have 5pistons fightin agains one, pistons will start flying through the hood... Nobody wants that, so a sweet position is the goal: max power, min harm.

Practically: adjust camp pos -sensor using timing light on the crank pulley timing mark. With coilpacks, extension cord is needed to get pulse/spark for timing light.

[BP2K2Max]

i had mine advanced from 15 degrees to 17 BTDC. the dealership did it for me at no charge using the OBD consult II scan tool. nissans manual says that anywhere between 15-20 degrees is still within what is considered "nissans specifcation" meaning anywhere in that range should not cause any harm to your engine. just be sure to use 91 or 93 octane or better if you have it done.

[SuperStock96]

So is 17 degrees the best position for a 5.5gen or does it vary for different mods you may have on the car?

[BP2K2Max]

17 or 18 seems to be where people feel safest. i don't think mods should really have an impact on what you decide to set your timing at.

[Nahkapohjola]

Originally Posted by SuperStock96

...does it vary ...

There is no single answer, setting depends how/who/where the car is used; at some adv point engine heads heat so much that ping starts, KS detects it, ECU retards ign = any benefits are lost
- Low octane
- At summer, reduced cooling
- Lots of city drive, low rpm, soot buildup
...may also cause the same

Its safe keeping the ign setting between the factory margins, nissan V6 it generally is plus/minus 2degrees. Going beyond five degrees will be teasing your luck; with some prerequisites some do get away with that - at least for a while.

I think you may safely adjust 5degrees - if things in the list above are observed. The engine is not harmed or doesnt die from first ping 'sound'; but if one keeps pushing the pedal in wrong circumstances, the total engine destruction will happen in couple of minutes (without KS/ECU ret.).

Without KS, you better know how to listen for ping and loosen the gas pedal if that happens, have right octane etcetc. For my VGE w/o KS, cold climate, this means 95 octane (lowest here) and 17degrees (stock is 15).

As you buy gas, you cannot know the octane by smell. Never. Maybe the day before the Oil-company tanker guy & gas station boy did accidentally mix the octane ratings at the gas station?
----> your friend loans your car. First he fills the empty car tank with 87octane, hits the road aggressively stereos blazing. Ten minutes later engine blows. Whose fault is this??? Doesnt matter, u pay anyway. Now the "Iknew -chorus" will be saying: "...didnt we tell you about the KS bypass danger...