Spark Plugs and Methanol Fuel

February 24, 2023, 04:31 PM

I did say Methanol, which I know is not Ethanol, but to me, alcohol is alcohol, and though E-85 is approximately 85 percent Ethanol, it is not purely an alky fuel. I was reading an article on Engine Labs, in which it stated the following:

"It’s not common knowledge in the performance industry that when using ethanol-based fuels, it is a requirement to run a very cold spark plug since fuel lights off very easily once it reaches its operating temperature. Cold spark plugs are necessary to prevent pre-ignition damage to engines using this type of fuel."
So here is my question. E-85 would fit their category of Ethanol-Based. But what about Methanol? I am guessing their statement does not apply, but am I wrong? Are the characteristics of "E" and "M" alcohols that different? I have been running Methanol for 7 years now, and it is hard to light off when temps are cold, and it runs very cool when temps are hot, So I always either use the same old -8 NGK plugs as I did on Race Gas when it is hot weather, or in the early and late season cool weather races I sometimes switch to a -7, to keep a bit more heat in the chambers. I have not experienced any detonation or pre-ignition, nor seen any evidence of it during routine plug checks or freshen-up. 12.7:1 compression, timing locked at 36*
What about you guys that run Methanol, do you use a hotter, cooler, or same heat-range plug as you would on gas?

February 24, 2023, 05:31 PM

vetman

Been on methanol since 2014 14.8 compression -8 plug 37 deg. timing no problems 358 inch small block chevy

February 24, 2023, 05:40 PM

markemark

388 / 14-1, EFI methanol / w 36* using -9 plug @ 35* to 100* air temps.

February 24, 2023, 08:28 PM

Curly1

I went to alcohol in 1998 and I did not find anything by changing plugs. I usually run -9 and around 30* timing.

By the way I have ran alcohol on motors from 9.4 Compression to 16 to one.

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February 24, 2023, 09:22 PM

wideopen231

started running alcohol in 1987/Ran injected and blown/NGK-9's both. Ran 8's and now trying 10's
on injection. Almost zero changes. With blown deal ran 32* dual mags and 36* single mag with 12.5:1 and as much as 64% od with 14-71. So pretty wide spread on uses and as said run with very little change when swapping up or down.

We run 10's with 95% nitro injected so very versitle plugs.

February 24, 2023, 11:14 PM

Alaskaracer

16.5:1, methanol, 36*+ on timing, mfi, NGK -9's when tuning, Autolite equivalent once tuned....works for me

February 27, 2023, 09:55 AM

BD104X

584" 15:1 BBC on alcohol, conventional Brodix head - NGK-9's

This message has been edited. Last edited by: BD104X,

March 17, 2023, 07:02 AM

M802138

quote:
Originally posted by Curly1:
I went to alcohol in 1998 and I did not find anything by changing plugs. I usually run -9 and around 30* timing.

By the way I have ran alcohol on motors from 9.4 Compression to 16 to one.

same here. Been messing with methanol powered equipment for over 30 years and have never found any improvement with colder spark plugs, contrary to what "everyone" said. Anywhere from 5.6:1 comp to over 16:1, gas plugs are methanol plugs and vise versa.

March 17, 2023, 09:35 AM

Eman

I ran gas, switched to methanol then went back to gas. Never changed plugs #7 NGK's look good and never missed a beat.

April 01, 2023, 10:13 PM

AlkyIROC

588 BBC 14.6:1 NGK -9, 37* timing, injected alcohol (twin flying toilets)

I never tried -10 plugs but the -9 puts the heat mark about half way up the ground strap in my engine so that's what I use. I also had to index all the plugs to keep the ground strap away from the huge piston dome.

Plugs are cheap. Buy a bunch in different heat ranges to see what works best.You want the coldest plug possible that doesn't foul up. If the plug fouls up, go hotter.

April 02, 2023, 07:24 AM

Bucky

OP, what are you referring to with "lights off"? On initial start up or during runs? The plug heat range has no effect on initial start up, since there is no heat at that point.

I changed to -10's when we added boost. I'm probably going to change to -8's this season.

I am curious if anyone here has noted how differently the strap shows the mark on different hottness of plugs.

April 02, 2023, 08:13 AM

RacerVX54

quote:
Originally posted by Curly1:
I went to alcohol in 1998 and I did not find anything by changing plugs. I usually run -9 and around 30* timing.

By the way I have ran alcohol on motors from 9.4 Compression to 16 to one.

Same zero difference in plugs. Ran the same plug on gas and alky.

April 02, 2023, 09:13 AM

Curly1

quote:
Originally posted by RacerVX54:
quote:
Originally posted by Curly1:
I went to alcohol in 1998 and I did not find anything by changing plugs. I usually run -9 and around 30* timing.

By the way I have ran alcohol on motors from 9.4 Compression to 16 to one.

Same zero difference in plugs. Ran the same plug on gas and alky.

I would add that I typically do not run extremely high compression which makes tuning window a little wider, safer and more forgiving. For me 14 maybe 15 is enough.

At 12.7 compression for original poster you should be good as is. And I do not think you would gain much if anything by changing heat range in plugs with in reason. Alcohol will always harder to start when cold. Nature of the beast. When it is cold outside I lean it out and get it hotter on return road and then put a blanket over motor between rounds.

April 02, 2023, 09:43 AM

markemark

If you see no difference switching from gas to methanol in plug range that you are using, does one see a difference in EGT’s using gas or methanol?

April 02, 2023, 04:40 PM

RacerVX54

quote:
Originally posted by Curly1:
quote:
Originally posted by RacerVX54:
quote:
Originally posted by Curly1:
I went to alcohol in 1998 and I did not find anything by changing plugs. I usually run -9 and around 30* timing.

By the way I have ran alcohol on motors from 9.4 Compression to 16 to one.

We are 14.5-1

Same zero difference in plugs. Ran the same plug on gas and alky.

I would add that I typically do not run extremely high compression which makes tuning window a little wider, safer and more forgiving. For me 14 maybe 15 is enough.

At 12.7 compression for original poster you should be good as is. And I do not think you would gain much if anything by changing heat range in plugs with in reason. Alcohol will always harder to start when cold. Nature of the beast. When it is cold outside I lean it out and get it hotter on return road and then put a blanket over motor between rounds.

April 02, 2023, 09:01 PM

Curly1

quote:
Originally posted by markemark:
If you see no difference switching from gas to methanol in plug range that you are using, does one see a difference in EGT’s using gas or methanol?

I do not know, I did not start running EGT's, O2 and Data loggers until after I had went to alcohol. I know that on my stuff the EGT's are virtually useless but the O2's have been very repeatable and reliable.

Also do not get into the trap where someone says you have to have 1100* EGT, 13.2 O2 or 38* timing. They do not know, you tune to the best MPH and ET on your car and then what ever the O2, EGT and timing is your baseline. Read your plugs and compare to time slips.

April 03, 2023, 06:25 AM

wideopen231

While Curly and I disagree about use of egt's. He is 100% dead on with no one temp is the number for everyones combo. The type of exhaust(zoomie vs collector) and number one thing sensor location have a huge effect on that number. Moving the sensor 1" away from head will have 100 to 200* difference in max number. Plus you do not need to be at max. Alky works better consistency-wise, if it is slightly rich. Meaning one stap from max.

I have two guys running injection that use one O2 WITH EGT'S. tHEY USE EGT NUMBER IN THAT CYLINDER and tune the rest to match. Should work some what for carb although you can not lean or richen each cylinder with a nozzle change.