l2aine

Okay this is what I've learned:

- when you advance the timing, you change the moment at which the spark plug fires. advance = plug fires later during the combustion cycle, retard = plug fires earlier in the combustion cycle.

- advancing or retarding timing does not make the spark hotter. You're not increasing spark voltage or anything like that by changing timing - you're just changing the "time" that the spark fires.

- higher octane fuel does not ignite as easily as low octane fuel. However, the combustion cycle still occurs in the same range, regardless of fuel octane level. Therfore if you run higher octane fuel you would want to try to light the fuel earlier in the combustion cycle so that all the fuel will be burnt once the cycle reaches the "exhaust" phase.

EX: say it takes 180 degrees to complete the "combustion" phase. Now let's say that low octane fuel takes 100 degrees of movement to fully ignite. You could time the ignition to spark at about 80 degrees from start, and you'll have 100 degrees left to ignite the low octane fuel.

Now say high octane fuel needs about 130 degrees of movement to completely combust. To make up for the extra degrees needed, you'd have to back the timing to about 50 degrees to allow for enough time so that the high octane fuel can combust completely.

Okay, now let's say "standard" timing for this engine was at 80 for low octane fuel (first example). Put in high octane and you don't give the high octane fuel enough time to fully combust. Now do the same thing, but ADVANCE the timing even more. See where this is going?

Anyhow, this is from what I've learned. If I got something wrong, someone correct me or comment so we can get this whole timing stuff straightened out

BigVinnie

iTrader: (2)

Yes I understand the compression phase's, but when you ignite at a later phase in compression "advanced timing" the spark plugs also increase in "temprature & spark". Resistors and capacitors "absorb heat" allowing to use more electrical current as it gets hotter, but also giving spark plugs a shorter life span, also sucking to much electrical juice from stock coil.
MSD even recomends for advanced timing and higher reving engines to install a blaster 2 coil for a strong electrical current passed 5000 RPM.
I saw that when you said that advanced timing didn't work for you the first thing I assumed was that you weren't getting enough elecrical current.
You should of gotten a significant power increase with advanced timing.
When I was part of a boo boo Honda CRX crew, we would advance the timing, also finding out that bad grounding significantly reduced HP and spark. Spark plugs as a resistor ground out to the engine, at the same time your engine grounds out to the chassi. If you are not properly grounded you won't get enough spark especially if your car is hitting that 10 year age.
I thought I would add my 2cent's, if it makes any sence to you.

BigVinnie

iTrader: (2)

Take an Acura RSX Type S it runs on a DIS system that advances itself, if you havent noticed Honda straps a ground wire from the head to the chassi for proper grounding. When vtec kicks in the DIS advances the timing to increase more power at higher reving, to keep the power band"torque curve stronger, and longer". Increasing the AWG size of the ground wire increases spark performance.
Also in respect to 3degress of timing, where did that come from can I get the link?
I was taught to use the grade fuel that you have, and advance the timing till you start to hear "knock and Ping" from the head.
Once you hear knock and Ping back off the advancing slightly and move to a higher grade fuel. The furthest I have gotten is 13 degress. I'm wondering how the other guy is getting 23degress it seems a bit extreme to me. I'm not even shure if you can even advance 23 degress in the distributor, but I would defenitely like to know how.

l2aine

I don't think he's at 23 degrees advanced - rather at just 23 degrees (stock timing is 20 degrees)

miked808

Its advanced 3 degrees for a total of 23 bdtc. But my Engine is also in tip top condition so there isn't any spark issues.

BigVinnie

iTrader: (2)

I am not saying that you are a liar but I am a bit skeptical, 20 degress to me is to far out of range from TDC. At 20 degress even; you almost mis compression, so I am wondering how you do it...... Please inform me........ I,ve only seen stroker engines detonate that far on ethanol fuel. Like I said the furthest I have gotten is 13degress and that is on 91octane before start to really get "knock and ping".
Big V

ArticDragon

Vinnie, read again. He advanced 3 degrees over stock.

l2aine

mikek808 didn't even write it right. he put "BDTC" when I think he meant "BTDC" or "before top-dead-center" - which is also wrong because he advanced his timing, not retarded it.

He is at 23 degrees ATDC (after top dead center). Stock timing setting for the KA24DE is at 20 ATDC. Therefore he has a 3 degree advance in his timing.

ONLY THREE DEGREES. NOT TWENTY THREE. LOL

Also, you're comparing a high-revving VTEC with DIS compared to a torquey 2.4 liter iron block. Sure DIS advances the timing, but you didn't address the changes VTEC applies to valve movement (something the KA24DE doesn't have) which can work together with advanced timing and other parameters to produce more power.

I still don't see how you keep saying that the spark gets hotter if you advance it. timing change by moving the distributor mechanically changes the point at which the spark ignites - it does nothing to increase voltage or current from the distributor to the spark plug. As far as I know, it doesn't change the voltage going to the spark, nor amplifies it, nor "gets to charge longer before lighting off"... so how do you explain the claim that an advanced timing setup has a hotter spark?

miked808

Thanks l2aine I always did get those backwards.

BigVinnie

iTrader: (2)

My bad!!!!!!!

BigVinnie

iTrader: (2)

The spark doesn't get hotter...... Sorry my english is really bad.....
As the compression within the cylinder gets hotter so do the spark plugs.... Hopefully that makes sence......
As resistors get hotter they pull more of an electrical static discharge......
It isn't anything in the distributor that causes the spark to increase, that is my bad if I said that......
If you apply a ground wire to the head, you will be able to discharge a "larger electrical current", hence "more HP & more spark". But honestly you only see a donkey or two when you do that.
If you are still confused I will download a pic from my chilton's manual from the Nissan Z24I, it explains the ratio in heat to advancing timing, and the life span of the plug.......

l2aine

Okay that makes more sense, but if you think about it compression is highest at TDC (therefore heat from the compresssion is highest) - once the piston starts going on its downstroke, the fuel mixture isn't being compressed anymore... plus I dunno but from what I've learned the heat generated from comression doesn't make the spark "hotter" and it doesn't light off the spark plug- the ignition does. the only type of engine I can think of that uses the heat from compression to light off the "spark" is in 2-strokes and deisels - both of which the KA is not.

Well, that's what I've learned... maybe someone else can jump in here and add more to it

BigVinnie

iTrader: (2)

HAHAHA I feel like the MAD Scientist today, here is the info, I must remind you that the specs vary " and are speculated" from different brand spark plugs, and compression of engines. This is the rating of your basic cheap champion spark plug.....
Yes Raine you are very correct and direct with your knowledge it's a damn shame i'm not as smart as you with my english... Here is the pic.....

ArticDragon

Diminishing returns past 6° I see.

rivneo1

Dont forget that we still got Iridium Spark plugs that we can use ,and those are more heat tolerant than platinum.