Rich Bowes
Member
I'm currently running my 1930 Roadster with Champion W16Y spark plugs that keep getting covered with carbon. What "hotter" spark plug can I use, and would they fit without adapters?
Hotter spark plug
- Thread starter Rich Bowes
- Start date
Mike V. Florida
Well-known member
You have something else wrong/different since many use that plug with no problems.
Mike V. Florida
Well-known member
Model A spark plug heat ranges
Champion W18 = close to original 3X
Depending on your driving habits, etc., a cooler plug may be the one for you:
Champion W-14 (cooler than W-18)
Champion W-10 (cooler than W-14)
Motorcraft TT-10 (same as W-14)
Autolite 3076 (same as W-14 and TT-10)
Also Champion W16Y which some people will argue that it's cooler than Champion W-18 but hotter than W-14 as the numbers would suggest. On the other hand, for years and listed as such on their official heat range chart, the engineers at Champion proclaimed that the Y means projected nose (which it is, you can tell by looking at it) and for this reason it is supposed to run hotter at slower speeds.
Conduct a proper heat range test as follows to see what is needed for your car and how you drive:
Drive around for at least 30 minutes to allow engine heat to build and then drive out someplace where you can run the car at a sustained speed on a straight road for a few miles without having to slow down or stop, very important.
Run the car up to the maximum speed in high gear that you would typically drive if you decided to drive fast and I don't mean dangerously high speed.
Hold the car at that sustained speed and without letting off the throttle, reach over and turn off the ignition. Let off the throttle, push in the clutch quickly and coast over to the side of the road. Open the hood and allow the engine to cool off a bit (allow to cool off completely if running an aluminum head).
Remove the spark plugs and examine the color and condition of the electrodes and insulators. The color will be a true indication of how hot or cold the plugs are running. But remember ... during the test if you let the engine slow down or let it idle and then check the plugs you will have changed the effects and not get a true indication. I've seen many a person let an engine idle, check the plugs and then claim they were just right only to discover later that the plug heat range was too hot.
It they are white, the plug is too hot. Go to a colder plug.
If they are black, they are too cold. Go to a hotter plug.
If they are a shade of tan, they are just about right.
Also understand that all this is not set in stone. A person who putts around at say, 35 or 40 MPH and never faster may need a hotter plug. The lower the combustion chamber temperature the hotter the plug should be. On the other hand, as conditions cause the combustion chamber temperature to rise, a colder plug may be necessary. You just don't want the plugs to be sooty black and foul out which means they're too cold or chalky white which means they're too hot. You want the plugs to be somewhere in between like light brown to grayish tan. However, slightly white may not be too bad unless it is "chalky white."
Keep in mind that the plug descriptions are for engines in good condition, correct carb mixture, good hot ignition, etc., etc.. One with bad rings for example can cause oil to get on a correct heat range plug and foul it out (short to ground down the side of the center electrode) where it won't fire. It will be black and oily.
On the other hand, a plug that is running too hot will turn chalky white or bright white. This can reduce the life of the plug or even cause the electrode to burn up. A plug can also get hot enough to glow which can ignite the mixture before the spark occurs (pre-ignition). This can be bad news... During pre-ignition the temperature inside the combustion chambers can reach WELDING temperatures in just a few seconds. The result is a hole can melt right in the middle of an aluminum piston! ... and to make matters worse it can be completely silent .. you won't hear it until it's too late .. no detonation sounds, knocks or pings.
The condition just described is for a plug with the wrong heat range (too hot) run in an engine in good condition, correct carb etc.. the same as described above. If it is known that the correct heat range plug was used then other causes such as too lean a fuel mixture, timing advanced too far, etc., etc., are overheating the plug.
This is where "reading the plugs" can be used to determine all sorts of engine problems. But as mentioned it must be known that the correct plug was used to start with.
The heat range test is used to make this determination. At the outset always choose a colder plug first if you are not familiar with the nature of the plugs said to be hotter. That way the worst thing that can happen is the plug can foul out whereas too hot a plug can cause the problems above.
This information is from Larry Brumfield the creator of the Brumfield High compression head.
Champion W18 = close to original 3X
Depending on your driving habits, etc., a cooler plug may be the one for you:
Champion W-14 (cooler than W-18)
Champion W-10 (cooler than W-14)
Motorcraft TT-10 (same as W-14)
Autolite 3076 (same as W-14 and TT-10)
Also Champion W16Y which some people will argue that it's cooler than Champion W-18 but hotter than W-14 as the numbers would suggest. On the other hand, for years and listed as such on their official heat range chart, the engineers at Champion proclaimed that the Y means projected nose (which it is, you can tell by looking at it) and for this reason it is supposed to run hotter at slower speeds.
Conduct a proper heat range test as follows to see what is needed for your car and how you drive:
Drive around for at least 30 minutes to allow engine heat to build and then drive out someplace where you can run the car at a sustained speed on a straight road for a few miles without having to slow down or stop, very important.
Run the car up to the maximum speed in high gear that you would typically drive if you decided to drive fast and I don't mean dangerously high speed.
Hold the car at that sustained speed and without letting off the throttle, reach over and turn off the ignition. Let off the throttle, push in the clutch quickly and coast over to the side of the road. Open the hood and allow the engine to cool off a bit (allow to cool off completely if running an aluminum head).
Remove the spark plugs and examine the color and condition of the electrodes and insulators. The color will be a true indication of how hot or cold the plugs are running. But remember ... during the test if you let the engine slow down or let it idle and then check the plugs you will have changed the effects and not get a true indication. I've seen many a person let an engine idle, check the plugs and then claim they were just right only to discover later that the plug heat range was too hot.
It they are white, the plug is too hot. Go to a colder plug.
If they are black, they are too cold. Go to a hotter plug.
If they are a shade of tan, they are just about right.
Also understand that all this is not set in stone. A person who putts around at say, 35 or 40 MPH and never faster may need a hotter plug. The lower the combustion chamber temperature the hotter the plug should be. On the other hand, as conditions cause the combustion chamber temperature to rise, a colder plug may be necessary. You just don't want the plugs to be sooty black and foul out which means they're too cold or chalky white which means they're too hot. You want the plugs to be somewhere in between like light brown to grayish tan. However, slightly white may not be too bad unless it is "chalky white."
Keep in mind that the plug descriptions are for engines in good condition, correct carb mixture, good hot ignition, etc., etc.. One with bad rings for example can cause oil to get on a correct heat range plug and foul it out (short to ground down the side of the center electrode) where it won't fire. It will be black and oily.
On the other hand, a plug that is running too hot will turn chalky white or bright white. This can reduce the life of the plug or even cause the electrode to burn up. A plug can also get hot enough to glow which can ignite the mixture before the spark occurs (pre-ignition). This can be bad news... During pre-ignition the temperature inside the combustion chambers can reach WELDING temperatures in just a few seconds. The result is a hole can melt right in the middle of an aluminum piston! ... and to make matters worse it can be completely silent .. you won't hear it until it's too late .. no detonation sounds, knocks or pings.
The condition just described is for a plug with the wrong heat range (too hot) run in an engine in good condition, correct carb etc.. the same as described above. If it is known that the correct heat range plug was used then other causes such as too lean a fuel mixture, timing advanced too far, etc., etc., are overheating the plug.
This is where "reading the plugs" can be used to determine all sorts of engine problems. But as mentioned it must be known that the correct plug was used to start with.
The heat range test is used to make this determination. At the outset always choose a colder plug first if you are not familiar with the nature of the plugs said to be hotter. That way the worst thing that can happen is the plug can foul out whereas too hot a plug can cause the problems above.
This information is from Larry Brumfield the creator of the Brumfield High compression head.
Patrick L.
Well-known member
If you want to stay with Champs, then maybe try a W20 or a W18Y if you want the extended tip.
I'm not big fan of Champ and usually replace them with Autolite. Most folks use the 3076, but, the 3077 is a step hotter and thats the one I prefer for the tired old engine.
Your friendly local spark plug store should have [ or be able to get] any of the above.
This is if the engine stuff like timing [ and lever position] and carburetor settings are all correct.
I'm not big fan of Champ and usually replace them with Autolite. Most folks use the 3076, but, the 3077 is a step hotter and thats the one I prefer for the tired old engine.
Your friendly local spark plug store should have [ or be able to get] any of the above.
This is if the engine stuff like timing [ and lever position] and carburetor settings are all correct.
Purdy Swoft
Well-known member
As the numbers get higher with Champion plugs the heat range gets higher as in W 18 , W 20, W 89 D and W 95 D being the hottest. These are all 7/8 spark plugs that fit the model A head with no need for an adapter . I run the Champion W 18 and they run clean for me even at slow stop and go driving. Most drive their model a's for short drives. The W16 Y is really too cold for short drives and is best for long drives with higher steady speed. In other words, the W 16 Y has a heat range of 6 while the W 18 has a heat range of seven. The extended tip of the W16 Y is of no advantage with the model A because they don't reach an rpm level where the extended tip starts to be an advantage. There is no listed heat range for the Champion 3X but is believed that the W 18 is closest to the heat range of the original 3X. If you want to use adapters the AC 45XLS works good with stock or compression ratios below 6 to one. Adapters alter the heat range of any spark plug. Because the adapter isn't actually part of the head, they can't transfer the heat the same as a spark that screws into the threads of the head instead of first having to go thjrough an adapter. One anvantage of the AC 45 XLS is that it has a top nut that screws on and off and can be used with original spark plug strip type wires.
30ccpickup
Well-known member
Good info on plugs. To follow up on Mike V's original comment, here are the simple things which could cause carbon on the plugs:
Driving with the ignition retarded
Driving with GAV mixture too rich
Driving to slow and on short trips
In need of ignition tune-up
Driving with the ignition retarded
Driving with GAV mixture too rich
Driving to slow and on short trips
In need of ignition tune-up
Last edited:
Rich Bowes
Member
Thanks for all the good info. I think I'll try the W18 plugs and a new ignition coil.
Purdy Swoft
Well-known member
I explained my experience in post #5 on the thread that Mike V shows above. If you are satisfied with the performance of the W16Y plugs and they aren't running black and sooty, there would be no reason to change. The advantage of spark plug adapters is that spark plugs would be in stock at any parts store that could be used with them. When the adapters are used with smaller modern spark plugs, at first glance, they appear to be original two piece plugs. I mentioned the AC 45 XLS long reach 14 mm spark plugs because they were used in the dyno tests with the Brumfield 5.9 heads. The AC plugs were too hot when I used them with a different head with compressioon around 6.8 and wanted to keep running after the switch was cut off. This is probably partly caused by the fact that adapters don't transfer the heat to the head the same as original spark plugs and the heat range actually increases .