Spark plugs

Or the new truths are wrong!

Glen

Well, in reality, nothing has changed OTHER than the capability to adjust on the fly. Piston engines still react the way they always have. You can adjust the timing to take advantage of higher octane fuel if you choose to do so. That was (is) common - adjust timing for maximum power with the specific fuel you plan to use. Obviously the best way to do it its on a dyno - advance the timing until the power drops off, then set to whatever produced the max. Of course, with a non-computer-controlled engine, if you set that way, you have to use THAT gasoline for best results and no concern about detonation. As I said in an earlier post, the shade-tree non-dyno way to do it was to advance the timing until it pings then back off the timing 2 degrees. That required a fair bit of accelerating up hill (preferably) and periodic stops by the side of the road to make timing adjustments.

Hey Glen , you in the flat earth society ?

Using NGK Iridiums since they were introduced into the UK. I have had more fake ones in my hand than genuine ones - you don't need to even look at them, the weight gives it away.
I have 2 new ones to replace the years old ones. NGK gave me the details of the online retailer they supply, thinking there would be quite a few, but no, just greenplugs here in the UK.
There is even a 'better' plug from NGK, not sure of the fitment, but it seems to be only available to the US and is over twice the price of the Iridiums.

MexicoMike said:

Well, in reality, nothing has changed OTHER than the capability to adjust on the fly. Piston engines still react the way they always have. You can adjust the timing to take advantage of higher octane fuel if you choose to do so. That was (is) common - adjust timing for maximum power with the specific fuel you plan to use. Obviously the best way to do it its on a dyno - advance the timing until the power drops off, then set to whatever produced the max. Of course, with a non-computer-controlled engine, if you set that way, you have to use THAT gasoline for best results and no concern about detonation. As I said in an earlier post, the shade-tree non-dyno way to do it was to advance the timing until it pings then back off the timing 2 degrees. That required a fair bit of accelerating up hill (preferably) and periodic stops by the side of the road to make timing adjustments.

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I power timed this same way for years and it worked quite well.
Then I learned a new way from Roy Robertson. Roy has a big bore Egli something like mine and set a British Land Speed record with it, somewhere around 170 mph.
He did extensive dyno tuning on that bike and learned that he could advance timing to 32 degrees after which pinging started.
He then started to retard timing to see how power dropped off and found that point at 22 degrees.
So he runs just 2 degrees advanced of that at 24. This produces the same power as the other end of the zone and is safer as far as holing pistons etc.
I followed his example and had Andy at Pazon make a special map with just 24 degrees max advance, Smartfire twin plug, twin driver ignition.
It's working well.

This is the opposite of my old method, advance to pre-ignition , then back off.

Glen

As my boat anchor doesnt like to start I may try retarding and see how it goes. Interesting but have to wonder if the experiment has been repeated by others.

Onder said:

Interesting but have to wonder if the experiment has been repeated by others.

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Yes. I’ve done very similar to what Glen describes, although I don’t go as far as having an EI made!

I’ve had several Brit bikes, road and race, on the dyno before. Whenever I have played with ign I have found there to be a quite large range of movement in advance that makes no difference whatsoever to the dyno reading (although, of course, there may be other effects to starting, running temp, etc). Roy had 10 degrees of range before he observed any effect at either end of that range, so our findings seem to support each other’s.

On my race bikes I did it Glens way and set the timing a few degrees advanced of any measured loss.

These days, mindful of the need for good kickstarting etc on my road bikes, I opt to keep them very close to stock, maybe just a couple of degrees retarded from the standard settings, assuming the dyno shows this to be good.

Perhaps it’s because Brit bikes were, in general, set quite advanced by the factory? But the notion that you can get more power just by randomly advancing the ign on a Brit bike is certainly not what I have ever seen.

I never advance further than stock. I do wonder if retarding has any effect on exhaust gas temps.

Onder said:

I do wonder if retarding has any effect on exhaust gas temps.

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It does if you go too far, as I found out (by accident) !

Fast Eddie said:

It does if you go too far, as I found out (by accident) !

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How far?

Has anybody run an EGT and gathered data?

Interesting discussionn on ignition advance, but does anyone have evidence that ignition advance curve has something specific to do with plug selection and fouling?

Of course it can, but I was wondering what experience with timing advance we should consider in making plug selections.

Onder said:

As my boat anchor doesnt like to start I may try retarding and see how it goes. Interesting but have to wonder if the experiment has been repeated by others.

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My experience has been that retarded ignition makes for reluctant starting.

Onder said:

Has anybody run an EGT and gathered data?

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Ah back in the good ole days.
Racer friend with BSA A50, I was pit crew/consultant for him in the 90's. He had lots of money. Bought all the "big bucks goodies" from the go fast people/suppliers. He assembled all the components to, unknown to me, specs.
Not that powerful but lots of fun on the racing chassis.
I offered a dyno session.
The initial run showed only 28RWHP? I measured EGT at well under 900 degrees F. Not good, too cold and would blacken the plugs real fast.
Jetting changes and we kept leaning out the jets again and again until a bit over 1325 deg F. Plugs staying clean and RWHP 42.
He said it never was as fast on the track as where the tune ended up.
FWIW
SInce then (mid 90"s), I have never bought a spark plug. I use peoples cast offs. I put black dirty plugs in my "maintained" amal carburated combat or MKIII. With one blast up the highway, I return to check the plugs that are now thermally burned clean.
It is said you must run the plug over 900f or the plugs won't stay clean. Selected heat range of the plug must reflect engine tune and driving style.

Triton Thrasher said:

My experience has been that retarded ignition makes for reluctant starting.

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Unfortunately electronic ignitions prevent a proper set up of ignitions.
A set up of 5-7deg BTDC will result in a easy and reliable fire up every time.
Every engine I build it set like that. My engines are almost always a 1 kick operation.

So you are, or are not, using EI on your bikes?

For some reason my Norton runs better with the N7Y plugs, when they had a bad batch way back in the 70s I tried other brand plugs with the same heat range and within a week would get a misfire from them so after a lot to of time replacing plugs and money went back to N7Y plugs and always get long life out of them, since putting the Joe Hunt maggie on over 7 years now I put a new set of N7Y plugs in set at 18thu for the JH and I have done about 30k mile on them and they look as good as the day they went in, with the hotter spark of the JH they run very clean and no sign of wear on the electrobe, when I do pull my plugs out to check them I look at them without even touching them and just put them back in, run with copper core plug leads as well.

Ashley

I always found when trying to get conventional (non computer-controlled) bike engines to run best, that OEM engine fuel mixtures needed to be leaner than what was supplied by the factory. I always assumed they jetted them rich because that's safer than too lean but max power was always made by going leaner, never by going richer.

Onder said:

So you are, or are not, using EI on your bikes?

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So far only Lucas Rita, points/coil or magneto for NHT or BSA A-10... no choice on the 3 Ducati: fuel injection and short dwell EI
I bought one analog boyer in the late 80's and never could convince myself to put one on my combat. I used it for my igniton research and testing. After I discovered the voltage depression spark scatter effect, I knew it would never go on my MKIII and I eventually sold it.

Old type Boyer on MK111, installed in the 80s
Generally 1 kick start, although I use the button mostly now, steady idle, goes good, 26,000 miles.
Boyer on 650ss, installed 1998.
Same running result as MK3, no complaints

Pazon Smartfire on one Vincent, no issues but low miles to date.

The rest of the herd are magnetos or point/coil or modern bikes with whatever EI they use.
Have had a few magneto problems.
Easycap seems to be a fix.

Glen