Pedro Posted January 18, 2011 Report Share Posted January 18, 2011 been doing a lot of reading on alcohol lately and cant figure out why people are running colder plugs when they switch to alky. I understand we gap them smaller so that the added flow doesnt turn the spark off. But why do we get colder plugs if methanol itself is supposed to make the motor run cooler? Quote Link to comment Share on other sites More sharing options...
camatv Posted January 19, 2011 Report Share Posted January 19, 2011 because people usually have a bad setup and run out of fuel or run lean after the carbs get low on fuel and were poping engines they related it to the hotneess of the plugs i have ran b8eix plugs on alky bikes with no problems but i also have plenty of fuel capacity and fuel flow. also i believe that the colder plugs can help keep a motor from poping iof its ran on the ragged edge. but i dont know.. Quote Link to comment Share on other sites More sharing options...
Hilarious Posted January 19, 2011 Report Share Posted January 19, 2011 also to help prevent detonation with all the added timing and compression. Quote Link to comment Share on other sites More sharing options...
tedd1 Posted January 19, 2011 Report Share Posted January 19, 2011 Prob'ly gonna be some shit, but here goes... When we say "a colder plug" we are referring to the heat range the plug was designed for. Fuel type, chamber shape, squish, and more all play a role in dictating what heat range plug is to be used. From >HERE< Heat range The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine head. Whether the plug is to be installed in a boat, lawnmower or racecar, it has been found the optimum combustion chamber temperature for gasoline engines is between 500°C–850°C. When it is within that range it is cool enough to avoid pre-ignition and plug tip overheating (which can cause engine damage), while still hot enough to burn off combustion deposits which cause fouling. The spark plug can help maintain the optimum combustion chamber temperature. The primary method used to do this is by altering the internal length of the core nose, in addition, the alloy compositions in the electrodes can be changed. This means you may not be able to visually tell a difference between heat ranges. When a spark plug is referred to as a “cold plug”, it is one that transfers heat rapidly from the firing tip into the engine head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter. An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber. The heat range numbers used by spark plug manufacturers are not universal, by that we mean, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for some manufacturers (Champion, Autolite, Splitfire and Bosch), the higher the number, the hotter the plug. For othe manufacturers (NGK and Denso), the higher the number, the colder the plug. Do not make spark plug changes at the same time as another engine modification such as injection, carburetion or timing changes as in the event of poor results, it can lead to misleading and inaccurate conclusions (an exception would be when the alternate plugs came as part of a single pre-calibrated upgrade kit). When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage It is generally accepted that, when you change to alky, you go to a colder range plug. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted January 19, 2011 Report Share Posted January 19, 2011 I actually run BR10EIX in one of my motors per builder recommendation. Off topic a tad here, but I also compared a few back to back passes with brand new plugs not gapped - straight out of the box, then gapped to 0.018". No change in e.t. or how the bike felt. Quote Link to comment Share on other sites More sharing options...
Pedro Posted January 20, 2011 Author Report Share Posted January 20, 2011 I actually run BR10EIX in one of my motors per builder recommendation. Off topic a tad here, but I also compared a few back to back passes with brand new plugs not gapped - straight out of the box, then gapped to 0.018". No change in e.t. or how the bike felt. what ignition are you running on that bike? mines wont run unless its gapped to .018 Quote Link to comment Share on other sites More sharing options...
J-Madd Posted January 21, 2011 Report Share Posted January 21, 2011 OEM. Timing at +8* or so. For the record, I do still gap them to 0.018". I just tried that to see. Better safe than sorry when it comes race time. Hate it lose because I didn't gap the plugs. Quote Link to comment Share on other sites More sharing options...
sheefreak Posted January 28, 2011 Report Share Posted January 28, 2011 OEM. Timing at +8* or so. For the record, I do still gap them to 0.018". I just tried that to see. Better safe than sorry when it comes race time. Hate it lose because I didn't gap the plugs. Some motors and ignitions need that smaller gap. JD's bike last summer was a perfect example. It would break up on the top end untill he gapped them at .018. I have seen a few others as well, some with weak or failing ignitions being the culprit. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted January 28, 2011 Report Share Posted January 28, 2011 I gap a bunch of plugs before a day at the track, normally 3-4 sets just to have on hand. I put mine in a vise and close them shut, then open them up to .018 to .020. I have run mine out of the box and have broken up on top end....and my ignition is solid, not real aggressive on the timing (7 I think...lol) or compression. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted January 28, 2011 Report Share Posted January 28, 2011 Maybe the iridium plugs can tolerate the wider gap. I never tried that with the standard B9ES. Quote Link to comment Share on other sites More sharing options...
camatv Posted February 4, 2011 Report Share Posted February 4, 2011 (edited) the tenny electrode IX plugs actually make the spark EASIER on the ignition on "weak" ignition systems.. its easier for the coil to jump the gap at higher rpm loads and fuels with those plugs... thats straight from NGK. thats why i likee them lil motors that like to REV will like a hot ignition and an irridum plug ( nology/ dyna CDI) might be why they didnt break up on top witht he larger box gap (.23?) but i would still gap them down to 18 just to be sure... Edited February 4, 2011 by camatv Quote Link to comment Share on other sites More sharing options...
camatv Posted February 4, 2011 Report Share Posted February 4, 2011 http://www.ngk.com/more_info.asp?AAIA=&pid=3177 Quote Link to comment Share on other sites More sharing options...
camatv Posted February 4, 2011 Report Share Posted February 4, 2011 oh and here is another tip no matter what ngk plug you are going to use try to get the NON removeable TIP i know it has happend to me that lil stupid tip unscrews and get stuck in the stinking cap... if i can avoid it i try to .. most any parts store that sells ngk can get the plugs for you i use o'reilly's they use the stock numbers use NGK's site to convert it and then give them the 4 digit number for them. http://www.ngk.com/more_info.asp?AAIA=&pid=3449 Quote Link to comment Share on other sites More sharing options...
dajogejr Posted February 4, 2011 Report Share Posted February 4, 2011 I learned that one a long time ago. Tighten the plug in the motor, then take some pliers/vice grips and give the tip of the spark plug a little tap to tighten it. Nothing worse than breaking up for something silly like that. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted February 4, 2011 Report Share Posted February 4, 2011 oh and here is another tip no matter what ngk plug you are going to use try to get the NON removeable TIP i know it has happend to me that lil stupid tip unscrews and get stuck in the stinking cap... if i can avoid it i try to .. most any parts store that sells ngk can get the plugs for you i use o'reilly's they use the stock numbers use NGK's site to convert it and then give them the 4 digit number for them. http://www.ngk.com/more_info.asp?AAIA=&pid=3449 I'll add that if you have the O'Reillys stock number it makes it much easier for them to find/order the plugs. BR10EIX= 6801 BR9EGV = 5827 BR9ES = 5722 I keep those in my phone so I don't spend 15 minutes standing around while they try to look them up. Quote Link to comment Share on other sites More sharing options...
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