Spark plug technology and choices

[kaweeka]

I added to a prior post about spark plug heat ranges after finding dry fouling on my BR8ES plugs in all cylinders. (Compression is good, 76-78/80) I run an IO 320 B1A with dual LSE Plasma III and AFP injection with 9:1 pistons. I typically fly LOP. Klaus' manual recommends the Denso IK27 which is actually a cooler plug that the NGKs in there now (the 8 heat range corresponds to a 24 in the Denso world). I wrote Klaus but, no surprise, haven't heard back. Using the 27, or even 24 when already noting fouling with the current NGK doesn't add up to me. While looking and reading, I came upon the website for Brisk Racing. There are myriad plug types and one that I am not familiar with called a multi-spark plug.

The description is this: "they produce more than one spark per impulse of the ignition system. More than one simultaneous point of ignition results in better and more spontaneous ignition of the air-fuel mixture. Spark Plug sparks are not shielded by the ground electrode; therefore it provides faster, unrestricted expansion of the flame front. The mixture burns more uniformly and more quickly. The result of better utilization of available combustion energy is more power, better acceleration, lower harmful exhaust emission and reduction in fuel consumption."

It says it is designed for high output ignition systems. Would this be applicable to my set-up? Has anyone used or considered this brand or specific plug before? I do tend to overthink things so I apologize in advance. I am NOT an engineer but want to learn and understand these questions as they arise. It makes me safer and better able to make decisions that are beneficial to my aircraft and flight safety. I appreciate any knowledge from you all.

Thanks and be well everyone,
David

[rv6ejguy]

I'd say if you are seeing actual fouling with NGK 8s in there, you are running far too rich or you have an oil consumption issue.

Thousands of aircraft are flying with NGK 8s or Denso 24s and 27s with no fouling issues so your engine seems to be the anomaly here.

I don't see any good reason to consider any other brands or type of plug for a stock Lycoming.

I've been building stock and race engines and working on them for 40 years but never heard of Brisk before and never seen one of their plugs installed in any engine yet they claim to be one of the largest manufacturers of spark plugs in the world. Hmmm. Wonder why Toyota, Subaru, Nissan, Honda, BMW etc. mainly fit NGK or Denso as OE?

[airguy]

Originally Posted by kaweeka

The description is this: "they produce more than one spark per impulse of the ignition system.

There's your snake oil, right there. Spark plugs do not generate multiple sparks per voltage pulse. The voltage will rise on the plug electrodes until you get a dielectric breakdown in one location, the spark forms there and discharges the voltage differential. It's not possible to get more than one spark from a single voltage pulse, even the "split-fire" plugs with two electrodes will either fire from one, or the other.

The only way to get multiple discharges per firing event is from the ignition system itself - the coil and whatever is driving it - not the spark plug. Some ignition systems are capable of putting more than one high-voltage pulse behind another, either the same polarity or opposite but still a high enough voltage to achieve breakdown on the spark plug tip. The spark plug simply reacts to a second voltage rise by generating a second spark - but no plug ever built is capable of making two sparks from one voltage rise.

[mike newall]

IO-360 with dual P-Mags, now done 400 plus hours on NGK BR9EIX, which was what Brad suggested. I buy them at O'Reilly's and they price match the best interweb prices.

Change them once a year whether or not, never had an issue.

[jliltd]

Sidebar:
A quick reminder to buy the type of spark plugs with solid tips rather than screw-on tips. NGK uses the same model number for both types. It only changes the part number to distinguish the difference between screw-on tip and solid-tip plugs. For the BR9EIX the proper NGK part number is 3089. The wrong part number is 3981. I have found most of the local automotive supply stores stock plugs are the screw-on type. Why NGK would use the same model number for both types boggles the mind.

My first set of NGKs (3981's) had the screw-on tips as I had no idea there were two types. I tightened them and then swaged them in place by indenting with a pair of dull dikes. Then I read here about the solid-tip being the better way to go so ordered a set of 3089 solid tips to swap out next oil change. Last week I did the first oil change on a fresh Barrett overhaul and while swapping out the plugs I discovered 4 out of 8 of them had loose tips. Eeek. That's 20 hours in service since new with staking to lock them in place. I did not expect a 50% loosening rate. Loose screw-on tips can cause arcing issues and missing.

Jim

[kaweeka]

I like the price of the NGK vs the Denso. The question is, should I use the 8 or 9 heat range with my IO 320 with 9:1?

[RV8JD]

Does anyone know if the Denso IK27 plugs have solid tips, screw-on tips, or offered both ways as the NGK's are?

[airtractor8]

Originally Posted by kaweeka

I like the price of the NGK vs the Denso. The question is, should I use the 8 or 9 heat range with my IO 320 with 9:1?

I am running NGK BR9EIX # 3089 solid tips on my 0320 H2AD with SDS CPI ignition on one side. It is standard with 9:1 CR. No problems noted. It never fouls them and they look good upon removal so the 9 heat range seems good.

[Ezburton]

I was just working on my CI and thought I would try the BR9EIX instead of the BR8EIX. What gap are people running with on these?

Thanks,

[yarddart]

Injected 320 using NGKBR8ES no problems RV 3B