I am running a model b with a snyders high comp head, 2 stromberg 81's, and an open header. The motor came with c 16 c plugs and they fouled out. I had a set of w16y's in a stock model a motor that I tried and they fouled out. I have been told to try a hotter set of plugs but I am having trouble finding out what plug to try. I have done allot of searches and found plenty of info on stock motors but nothing on one that is juiced up a bit. Any help would be appreciated, what do you guys think. Thanks
Model b spark plug question
- Thread starter hudson-b
- Start date
Purdy Swoft
Well-known member
Champion W 18
J Franklin
Well-known member
Fouling can be caused by operating too cold. do you run a thermostat? What temp? You can also run the gap a bit closer .025 - .030. are the carbs running rich or lean?
Jim Brierley
Well-known member
Higher compression usually requires a colder plug. Your symptoms indicate a hotter plug is needed. Although J. Franklin's suggestions are good, if I were going to change the gap wider is usually better for fouling.
This is my actual experience with plugs.
My B engine with 5.2 head and Zenith carb ran just fine with C16C plugs for many (20 or more) years. I lived 25 miles from town so engine got good and hot every time with speeds of 55 to 60.
Then I moved to town ... many more short trips with maximum of 10 miles. Plugs were black and sooty. I tried the W16Y and 3076. Still sooty.
Now I have 3077s a hotter plug. Works just fine with the short trips. (I will have to be careful and test plugs if I return to long trips again)
I have been told that TT15 plugs are in the same heat range as 3077.
It makes a big difference how the car is used when selecting plugs.
Info from Larry Brumfield
http://www.fordbarn.com/forum/showthread.php?t=6458&highlight=hotter+colder
And this info also:
Think it was posted by Larry Brumfield
They are also not all the ones that I know of. The plugs are listed from hotter down to colder:
Champion:
W95D
W89D
WI6Y
C95F
W20
W14
WI 0
W85N
W8ON
Also the original 3X and W18 which Champion lists as norm and I believe they are both hotter than W-16Y.
Motorcraft (hotter down to colder):
TTI5 (the same as Champion W89D)
TT1O (“ Champion W14)
TT8 ( “ Champion W14)
TT4 ( “ Champion WI0)
Autolite:
3077 (this plug was not included in Larry's posting)
3076 (the same as Champion WI 4 and Motorraft UI 0)
Mopar (hotter down to colder):
P-9-7S
P-9-6S
P-9-5S
Prestolite (hotter down to colder):
78-10
78-8
S t i t t (hotter down to colder): "Censor did not like"
137 BSP
197
147 B
13/10
A heat range test is the best way to determine the correct plug for a particular engine set up and a person’s driving habits. When in doubt always choose a colder
My B engine with 5.2 head and Zenith carb ran just fine with C16C plugs for many (20 or more) years. I lived 25 miles from town so engine got good and hot every time with speeds of 55 to 60.
Then I moved to town ... many more short trips with maximum of 10 miles. Plugs were black and sooty. I tried the W16Y and 3076. Still sooty.
Now I have 3077s a hotter plug. Works just fine with the short trips. (I will have to be careful and test plugs if I return to long trips again)
I have been told that TT15 plugs are in the same heat range as 3077.
It makes a big difference how the car is used when selecting plugs.
Info from Larry Brumfield
http://www.fordbarn.com/forum/showthread.php?t=6458&highlight=hotter+colder
And this info also:
Think it was posted by Larry Brumfield
They are also not all the ones that I know of. The plugs are listed from hotter down to colder:
Champion:
W95D
W89D
WI6Y
C95F
W20
W14
WI 0
W85N
W8ON
Also the original 3X and W18 which Champion lists as norm and I believe they are both hotter than W-16Y.
Motorcraft (hotter down to colder):
TTI5 (the same as Champion W89D)
TT1O (“ Champion W14)
TT8 ( “ Champion W14)
TT4 ( “ Champion WI0)
Autolite:
3077 (this plug was not included in Larry's posting)
3076 (the same as Champion WI 4 and Motorraft UI 0)
Mopar (hotter down to colder):
P-9-7S
P-9-6S
P-9-5S
Prestolite (hotter down to colder):
78-10
78-8
S t i t t (hotter down to colder): "Censor did not like"
137 BSP
197
147 B
13/10
A heat range test is the best way to determine the correct plug for a particular engine set up and a person’s driving habits. When in doubt always choose a colder
Last edited:
Re: Model b spark plug question-Spark plug Heat range testing.
From Ahooga.com
Here is test that Larry B talks about in post above:
Conduct proper Heat Range Test as follows ...
Posted by Larry Brumfield on Sep. 18, 2011 at 22:45:13
In Reply to: Re: Spark Plug Heatrange
posted by Harrie Burdan on Sep. 18, 2011 at 21:28:24
Conduct a proper heat range test as follows:
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 ... durng 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.
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 my 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.
As noted in the above text caution should be used when changing from a colder plug to a hotter one!!
From Ahooga.com
Here is test that Larry B talks about in post above:
Conduct proper Heat Range Test as follows ...
Posted by Larry Brumfield on Sep. 18, 2011 at 22:45:13
In Reply to: Re: Spark Plug Heatrange
posted by Harrie Burdan on Sep. 18, 2011 at 21:28:24
Conduct a proper heat range test as follows:
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 ... durng 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.
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 my 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.
As noted in the above text caution should be used when changing from a colder plug to a hotter one!!
Last edited:
Thanks for the suggestions and info. It seems that I am jumping the gun a bit and don't know what I need yet. I am early in the project and only have the chassis done. The longest the motor has been run is long enough to circle the block a couple of times sitting on milk crate attached to the frame. With the info you guys have given me it seems I need get the project done and determine what kind of driving I will be doing. Tomorrow I will head to my local parts store and bang my head against the wall while trying to find acouple sets of the suggested plugs, then end up going home empty handed and ordering them off the Internet.
Hint:
Champion has changed their number system ... At least at Car Quest and several others that I tried.
The kid at the parts store may not be able find the older plug numbers atleast by these old numbers listed here.
I ask for W89D ... (blank look)
"What car is this for? WHAT?
Oh our computer does not list a car that far back or any of those numbers."
I found an older guy that knew enough to cross reference the numbers in a book.
Ones I remember are:
W95D 562
W89D 589
W16Y 561
W20 520
W18 518
W14 514?
Some stores used:
W16Y CHA-561 for example.
Some of the stores are very high priced for some reason ... $7.00 to 32.00 per plug. Check around. I found the 3077 for 2.99 at Napa.
Champion has changed their number system ... At least at Car Quest and several others that I tried.
The kid at the parts store may not be able find the older plug numbers atleast by these old numbers listed here.
I ask for W89D ... (blank look)
"What car is this for? WHAT?
Oh our computer does not list a car that far back or any of those numbers."
I found an older guy that knew enough to cross reference the numbers in a book.
Ones I remember are:
W95D 562
W89D 589
W16Y 561
W20 520
W18 518
W14 514?
Some stores used:
W16Y CHA-561 for example.
Some of the stores are very high priced for some reason ... $7.00 to 32.00 per plug. Check around. I found the 3077 for 2.99 at Napa.
Last edited:
Jim Brierley
Well-known member
Having just driven it around the block it is too early to decide if you need different plugs. The engine needs to be run under load for awhile to get a correct read on the plugs.