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160 or 140 Thermostat?
It seems most new boats have a 160 thermostat these days. I have a '93
Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. |
160 or 140 Thermostat?
On Mon, 23 Feb 2004 20:10:04 +0000, Geoff 93 RRC wrote:
It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. Raw-water cooled or FWC (with heat exchanger)? I'd say if FWC, definitely go with 160. Raw-water, I donno - I guess you should be OK if you're in fresh water... Lloyd Sumpter "Far Cove" Catalina 36 |
160 or 140 Thermostat?
On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC"
wrote: It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. ============================================== 160 is OK for fresh water usage but not for salt water. |
160 or 140 Thermostat?
On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC"
wrote: It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. Ok, I've a different opinion. I prefer to run a little cooler thermostat with a hotter plug. I've done this on my antigue trucks and this technique works great. If you are looking for power and clean combustion, a hotter plug is always the best choice over fooling around with the thermostat. You have to remember that the reason you have a thermostat is to maintain a constant temperature on the block for expansion/contraction reasons - not for combustion. Combustion is strictly the pervue of how hot the spark is. Curiosity question - raw water cooled or fresh. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
"Wayne.B" wrote in message ... ============================================== 160 is OK for fresh water usage but not for salt water. Why is that? Thanks, Rich |
160 or 140 Thermostat?
"Rich" wrote in message . com... "Wayne.B" wrote in message ... ============================================== 160 is OK for fresh water usage but not for salt water. Why is that? Thanks, Rich Salt will have a bigger tendency to plate the inside of the engine with the higher temps thermostat. Bill |
160 or 140 Thermostat?
"Short Wave Sportfishing" wrote in message ... On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: If you are looking for power and clean combustion, a hotter plug is always the best choice Actually, the heat range of the plug only refers to the plugs ability to transfer heat from the plug to the head. A hot plug is one that that the tip retains more heat, a cold plug transfers heat quickly. When driving, the tips of the spark plugs are heated to incandescence. The heat must travel from the tip through the shell and ultimately into the water jacket of the cooling system. If the plug is too cold it will foul, if its too hot you will get detonation, that is, the fuel will ignite before the timed spark -- and you can blown a hole through the piston! The octane rating of the fuel and compression ratio will determine the correct heat range plug to use. Unless you have modified the engine, stick to the manufacturers recommendation. Rich |
160 or 140 Thermostat?
"Short Wave Sportfishing" wrote in message ... On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: If you are looking for power and clean combustion, a hotter plug is always the best choice Actually, the heat range of the plug only refers to the plugs ability to transfer heat from the plug to the head. A hot plug is one that that the tip retains more heat, a cold plug transfers heat quickly. When driving, the tips of the spark plugs are heated to incandescence. The heat must travel from the tip through the shell and ultimately into the water jacket of the cooling system. If the plug is too cold it will foul, if its too hot you will get detonation, that is, the fuel will ignite before the timed spark -- and you can blown a hole through the piston! The octane rating of the fuel and compression ratio will determine the correct heat range plug to use. Unless you have modified the engine, stick to the manufacturers recommendation. Rich |
160 or 140 Thermostat?
|
160 or 140 Thermostat?
On Tue, 24 Feb 2004 00:00:37 GMT, "Rich" wrote:
"Short Wave Sportfishing" wrote in message .. . On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: If you are looking for power and clean combustion, a hotter plug is always the best choice Actually, the heat range of the plug only refers to the plugs ability to transfer heat from the plug to the head. A hot plug is one that that the tip retains more heat, a cold plug transfers heat quickly. When driving, the tips of the spark plugs are heated to incandescence. The heat must travel from the tip through the shell and ultimately into the water jacket of the cooling system. If the plug is too cold it will foul, if its too hot you will get detonation, that is, the fuel will ignite before the timed spark -- and you can blown a hole through the piston! It is my understanding that a "hot" plug is aimed more towards keeping heat available to burn off deposits quicker and help with a cleaner, quicker burn when the fuel/air mixture is ignited. It is also my understanding that engine manufacturers allow for a range of types of hot to cold plugs to adjust for varying conditions like altitude, emissions requirements and other issues. I have adjusted plugs for hot/cold on high performance engines because of the varying temperatures in different cylinders - all within a range of course but all on the same engine. Perhaps I should have said Hottest Recommended Plug? Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
On Mon, 23 Feb 2004 23:22:55 GMT, "Rich" wrote:
"Wayne.B" wrote in message .. . 160 is OK for fresh water usage but not for salt water. Why is that? ========================================= Salt begins to precipitate out of solution as temperatures increase and will cause clogged cooling passages. |
160 or 140 Thermostat?
If this were true, there would be no need for a choke
on a carbed engine. Short Wave Sportfishing wrote: On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. Ok, I've a different opinion. I prefer to run a little cooler thermostat with a hotter plug. I've done this on my antigue trucks and this technique works great. If you are looking for power and clean combustion, a hotter plug is always the best choice over fooling around with the thermostat. You have to remember that the reason you have a thermostat is to maintain a constant temperature on the block for expansion/contraction reasons - not for combustion. Combustion is strictly the pervue of how hot the spark is. Curiosity question - raw water cooled or fresh. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
"Geoff 93 RRC" wrote in message m... It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? You probably would not notice a difference in engine performance or efficiency during normal boating operation. MercCruiser uses a 140 degree thermostat in the same 4.3 engine that Volvo and the former OMC use with a 160 degree version. Bill Grannis service manager |
160 or 140 Thermostat?
The boat is fresh water cooled. What hotter range plug would you recommend
and how much hotter is it than the standard plug? Thanks, Geoff "Short Wave Sportfishing" wrote in message ... On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. Ok, I've a different opinion. I prefer to run a little cooler thermostat with a hotter plug. I've done this on my antigue trucks and this technique works great. If you are looking for power and clean combustion, a hotter plug is always the best choice over fooling around with the thermostat. You have to remember that the reason you have a thermostat is to maintain a constant temperature on the block for expansion/contraction reasons - not for combustion. Combustion is strictly the pervue of how hot the spark is. Curiosity question - raw water cooled or fresh. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
Woops, I meant raw water cooled - no heat exchanger. I think I am sticking
with the cooler 143 degree thermostat. We boat on Lake Travis in Austin, TX and although very clean, its "hard" water. I have the scale on my outdrive to prove it. Seems the cooler running temps will limit mineral precipation as it does for sea salt. Thanks for all of the replies. "Geoff 93 RRC" wrote in message m... The boat is fresh water cooled. What hotter range plug would you recommend and how much hotter is it than the standard plug? Thanks, Geoff "Short Wave Sportfishing" wrote in message ... On Mon, 23 Feb 2004 20:10:04 GMT, "Geoff 93 RRC" wrote: It seems most new boats have a 160 thermostat these days. I have a '93 Mercruiser 4.3LX. Can I use the 160 thermostat? I boat exclusively in fresh water. I want to get the cleaner combustion that the higher temps give. Ok, I've a different opinion. I prefer to run a little cooler thermostat with a hotter plug. I've done this on my antigue trucks and this technique works great. If you are looking for power and clean combustion, a hotter plug is always the best choice over fooling around with the thermostat. You have to remember that the reason you have a thermostat is to maintain a constant temperature on the block for expansion/contraction reasons - not for combustion. Combustion is strictly the pervue of how hot the spark is. Curiosity question - raw water cooled or fresh. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
On Tue, 24 Feb 2004 02:36:53 GMT, Jim Kelly wrote:
If this were true, there would be no need for a choke on a carbed engine. Huh? What does choking an engine (limiting the air in the fuel mixture for a quicker start) have to do with hot plugs? Just curious. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
I am questioning your assertion that "combustion is strictly the pervue
of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I agree with your contention that mechanical clearances in the engine are designed around a certain operating temperature. If the engine is operating above or below the design temperature, thermal expansion rates of the materials in the engine will result in clearances that are different than the design criteria. Short Wave Sportfishing wrote: On Tue, 24 Feb 2004 02:36:53 GMT, Jim Kelly wrote: If this were true, there would be no need for a choke on a carbed engine. Huh? What does choking an engine (limiting the air in the fuel mixture for a quicker start) have to do with hot plugs? Just curious. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote:
I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
"Short Wave Sportfishing" wrote in message ... On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote: I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 Wrong! A hotter plug only keeps you from fouling at the temperature you are running. No hotter spark. Same coil and ignition driving the EMF. Same gap normally. A hotter plug, just does not transfer as much heat in the same time as cold plug. The heat is transferred to the head and cooling system. If you are running a cold engine, the burn is not as complete and with a normal heat range plug, it would foul and not fire. The hotter range plug just allows the carbon to burn off. Ideal would be a ceramic engine, that allows you run real high temps with out melting the piston, etc. Could get even more energy out of the gallon of gas. When starting, all the plugs are cold. More gas as the volatility of the fuel, does not allow as much vapor to ignite, so more fuel == more vapor. Why you get lots of carbon (black smoke) out the tail pipe on an engine with a stuck choke. |
160 or 140 Thermostat?
But the heat range of the plug is only a function of the heat transfer rate of
the insulator. Hotter plugs have a longer path from the tip to the metal body which transfers the heat to the head. So the tip of a hotter plug wood maintain a higher temperature. However, any plug capable of igniting combustion will create the same reaction in the combustion chamber and deliver the same amount of power. A hotter plug may have less of a tendency to foul if this is a problem. Short Wave Sportfishing wrote: On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote: I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
This is true. As you noted, the heat carried away by the cooling system does no
work. If it were economically feasible, using materials such as ceramics, to run higher combustion chamber temperatures, efficiency would indeed increase. Calif Bill wrote: "Short Wave Sportfishing" wrote in message ... On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote: I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 Wrong! A hotter plug only keeps you from fouling at the temperature you are running. No hotter spark. Same coil and ignition driving the EMF. Same gap normally. A hotter plug, just does not transfer as much heat in the same time as cold plug. The heat is transferred to the head and cooling system. If you are running a cold engine, the burn is not as complete and with a normal heat range plug, it would foul and not fire. The hotter range plug just allows the carbon to burn off. Ideal would be a ceramic engine, that allows you run real high temps with out melting the piston, etc. Could get even more energy out of the gallon of gas. When starting, all the plugs are cold. More gas as the volatility of the fuel, does not allow as much vapor to ignite, so more fuel == more vapor. Why you get lots of carbon (black smoke) out the tail pipe on an engine with a stuck choke. |
160 or 140 Thermostat?
"Jim Kelly" wrote in message ... I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. You have the right idea. The spark delivered to the combustion chamber is the same regadless of the plugs heat range. The only way to get a hotter spark is if you use a hotter coil. And using a hotter plug than the manufacturer recommends is can damage the engine. You will always need a richer mixture in a cold engine, the fuel doesn't atomize as well when cold. I installed an aftermarket programable fuel injection in my truck. It takes 30-40% more fuel for cold starts. Rich |
160 or 140 Thermostat?
On Wed, 25 Feb 2004 03:48:02 GMT, "Calif Bill"
wrote: "Short Wave Sportfishing" wrote in message .. . On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote: I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 Wrong! A hotter plug only keeps you from fouling at the temperature you are running. No hotter spark. Same coil and ignition driving the EMF. Same gap normally. A hotter plug, just does not transfer as much heat in the same time as cold plug. The heat is transferred to the head and cooling system. If you are running a cold engine, the burn is not as complete and with a normal heat range plug, it would foul and not fire. The hotter range plug just allows the carbon to burn off. Ideal would be a ceramic engine, that allows you run real high temps with out melting the piston, etc. Could get even more energy out of the gallon of gas. When starting, all the plugs are cold. More gas as the volatility of the fuel, does not allow as much vapor to ignite, so more fuel == more vapor. Why you get lots of carbon (black smoke) out the tail pipe on an engine with a stuck choke. Ah - well then apparently I was operating under a misunderstanding then. Although my anecdotal experience led me to believe otherwise. Hey, can't know every thing right? Thanks for the lesson everybody - learn (or in this case relearn) something everyday. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
On Wed, 25 Feb 2004 04:34:41 GMT, Jim Kelly wrote:
This is true. As you noted, the heat carried away by the cooling system does no work. If it were economically feasible, using materials such as ceramics, to run higher combustion chamber temperatures, efficiency would indeed increase. I made an assumption that I shouldn't have based on anecdotal experience with my two antique Internationals. Learn something new everyday. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 |
160 or 140 Thermostat?
Short Wave Sportfishing wrote in message . ..
It is my understanding that a "hot" plug is aimed more towards keeping heat available to burn off deposits quicker as in, burn the deposits off the plug itself so the plug stays clean. and help with a cleaner, quicker burn when the fuel/air mixture is ignited. Once ignition has taken place, the spark is no longer a positive influence to enhance the burn, the ball is rolling, the cat is out of the bag, Elvis has left the building. A dirty plug will not give a consistent spark on every compression stroke, so poor running will result. A plug too hot will pre-ignite. In between is a plug that stays hot enough to stay clean but cool enough not to pre-ignite. The penalty for getting too hot a plug may be the purchase of a new piston. It is also my understanding that engine manufacturers allow for a range of types of hot to cold plugs to adjust for varying conditions like altitude, emissions requirements and other issues. I have adjusted plugs for hot/cold on high performance engines because of the varying temperatures in different cylinders - all within a range of course but all on the same engine. That's an interesting idea. Assuming there isn't a problem of uneven ring wear or uneven carburetion, or uneven crankcase condensate drain (on a 2-stroke), then you may be left with a slight unevenness of head temp from one cylinder to the next. In that context it makes perfect sense to run a hotter plug on a cold cylinder, or vise versa, to lessen fouling of the plug in the cold cylinder or lessen pre-ignition in the hot cylinder. What you're doing is getting the plugs to be at about the same temperature despite the uneven head temp. %mod% |
160 or 140 Thermostat?
|
160 or 140 Thermostat?
Short Wave Sportfishing wrote in message . ..
On Tue, 24 Feb 2004 02:36:53 GMT, Jim Kelly wrote: If this were true, there would be no need for a choke on a carbed engine. Huh? What does choking an engine (limiting the air in the fuel mixture for a quicker start) have to do with hot plugs? I think he was responding to: You have to remember that the reason you have a thermostat is to maintain a constant temperature on the block for expansion/contraction reasons - not for combustion. Combustion is strictly the pervue of how hot the spark is. Gasoline will ignite only within a range of mixtures with air. While the block is cold, fuel in the mixture condenses on the cold surfaces so there is not enough fuel in vapor phase to be ignited by spark. Thus, the choke is closed to introduce more fuel to get the mixture right, till the engine "warms up." So we see that one function of the thermostat is to keep the block warm enough to eliminate fuel condensation, for purposes of combustion. And we see that combustion is the pervue of not only how hot the spark is, but also air/fuel mixture. %mod% |
160 or 140 Thermostat?
"Short Wave Sportfishing" wrote in message ... On Wed, 25 Feb 2004 03:48:02 GMT, "Calif Bill" wrote: "Short Wave Sportfishing" wrote in message .. . On Wed, 25 Feb 2004 02:01:22 GMT, Jim Kelly wrote: I am questioning your assertion that "combustion is strictly the pervue of how hot the spark is." I contend that that it is necessary to increase the fuel to air ratio on a cold engine because the engine is not imparting enough heat to the mix to create a combustible mix regardless of the heat range of the plug. Therefore, engine temperature has a direct effect on combustion. I can agree with that. However, combustion has to be initiated by the spark. The fact that a cylinder is operating at certain temperature only assures that the fuel/air mix on entering the chamber is fairly evenly dispursed. The source of ignition is still the spark. A hotter spark means that more energy is imparted to the explosive mixture resulting in a cleaner burn with more energy transfer. The gas expansion rate is better because the burn is initiated quicker. Additionally, a hotter plug in a cold normally aspirated engine means that one can use less choke on starting. Faster start, faster warm up. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 Wrong! A hotter plug only keeps you from fouling at the temperature you are running. No hotter spark. Same coil and ignition driving the EMF. Same gap normally. A hotter plug, just does not transfer as much heat in the same time as cold plug. The heat is transferred to the head and cooling system. If you are running a cold engine, the burn is not as complete and with a normal heat range plug, it would foul and not fire. The hotter range plug just allows the carbon to burn off. Ideal would be a ceramic engine, that allows you run real high temps with out melting the piston, etc. Could get even more energy out of the gallon of gas. When starting, all the plugs are cold. More gas as the volatility of the fuel, does not allow as much vapor to ignite, so more fuel == more vapor. Why you get lots of carbon (black smoke) out the tail pipe on an engine with a stuck choke. Ah - well then apparently I was operating under a misunderstanding then. Although my anecdotal experience led me to believe otherwise. Hey, can't know every thing right? Thanks for the lesson everybody - learn (or in this case relearn) something everyday. Later, Tom S. Woodstock, CT ---------- Basic Fishing Program: 10 - Fish 20 - Eat 30 - Sleep 40 - Goto 10 And if you run a really hot plug, the plug can burn up under heavy load. Used to race cars and used a hot plug when working on the car in the garage. got to the track late once (more than once) and left the garage plugs in the motor. Ran good in practice for about 10 minutes, then started missing. When I pulled the plugs the center electrodes were mostly gone. Bill |
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