Would you recommend a hotter plug?
 

New Engine, 800 miles, 6.0 head, larger intakes. Gav is usually closed or 1/8 of a turn.

They all look a little dark and sooty to me would you recommend a hotter plug. If yes, what should I use? I am using W16y.

Gap is 30.
90 90 82 90 compression

Re: Would you recommend a hotter plug?
 

If it is just a little soot then maybe a W18y (I think that is the hotter plug). But, without a picture, they sound normal. Mine at black and tad sooty and I run 3X which were the original plug.

Mike

Re: Would you recommend a hotter plug?
 

The insulator is what you need to look at. They will be sooty around the outer and that is normal. Posting a picture will help. What is your mpg average? You could have a timing or carburetor problem.

Re: Would you recommend a hotter plug?
 

Normally with higher compression the engine needs a colder plug but I think your present plugs should be about right. 6:1 is not very high. Plugs should be read after a medium length run, and not idled at the end of the run.

Re: Would you recommend a hotter plug?
 

Check your gap, I would change to 35. Enjoy.

Re: Would you recommend a hotter plug?
 

Champion W16 Y plugs were too cold for my use . I now run Champion W18 in mine , even the ones with 5.9 heads and they run clean . Ford finally recommended a gap of .035 and that is what I use, regardless of compression ratio .

Re: Would you recommend a hotter plug?
 

Sorry, I had photos but I forgot to send them. Let me know what you think.

Re: Would you recommend a hotter plug?
 

My opinion they look fine. Mine look the same. Are you happy with the performance? If you are, don’t fix it.

Re: Would you recommend a hotter plug?
 

Thats about the way mine looked before changing to W18 Champion plugs . Low speed stop and go driving can contribute to sooty plugs . After your engine gets more miles on it and gets driven longer distances at cruising speeds it should improve . If not, try hotter plugs .

Re: Would you recommend a hotter plug?
 

Don't run with the gav out too far after the engine warms up. It can soot up the plugs.

Brian

Re: Would you recommend a hotter plug?
 

The following 7/8"-18 spark plugs will fit the Model A and were available as of a few years back. They are also not all the ones that I know of.

Champion (hotter down to colder):

W95D
W89D
W16Y
W20
W18
W14
W10
W85N
W80N

Also the original 3X and W18 which Champion lists as norm. Also according to Champion, the W16Y is hotter than the W18 at low speed but cooler at high speeds over 5500 RPM....(over 5500 RPM? ... maybe Speedy ED J, Pete, George Miller, Dennis Pierce would be interested... maybe even Brent)

Motorcraft (hotter down to colder):

TT15 (the same as Champion W89D)
TT10 (the same as Champion W14)
TT8 (the same as Champion W14)
TT4 (the same as Champion W10)

Autolite:

3076 (the same as Champion W14 and Motorcraft TT10)

Mopar (hotter down to colder):

P-9-7S
P-9-6S
P-9-5S

Prestolite (hotter down to colder)

78-10
78-8

Stitt (hotter down to colder)

137 BSP
197
147 B
13/10

Range is a key word when one speaks of heat range.

Reading these Champion numbers is not real difficult. For example, W20 or W18, etc.:

The W is the shell design and it always means 7/8-18.

I should also add that Champion has made changes over time. For example a C-16C, used in many a Model A, starts with a C, BUT it is a 7/8-18 plug. It was discontinued about 1979 and replaced by the W16Y. There are many like this.

The number is the heat range and the lower the cooler (unless other letters immediately follow, like Y for example, which depending on the letter or letters can change or affect the heat range):

1- 25 = Automotive and small engines

25 - 50 = Aviation

51 - 75 = High Performance

75 - 99 = Industrial and Special Applications
by Larry Brumfield

Re: Would you recommend a hotter plug?
 

Larry also wrote this to test plugs,

"Reading the plugs" can be used to determine all sorts of engine problems. BUT, it must be known that the correct plug was used to start with before any problems occurred.

A heat range test is the best way to determine the correct spark plug for a particular engine set up and a person's driving habits. When in doubt always choose a colder plug first until you determine what works best. The worst thing that can happen is the plug can foul out whereas too hot a plug can cause pre-ignition and possible piston damage, i.e., a hole melted right through the piston! Some of you may think it's baloney but it's the truth.

Conduct a heat range test as follows:

Drive out someplace where you can run the car at a sustained speed for a few miles without having to slow down or stop; very important. This allows the heat to build.

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 right quick and coast over to the side of the road. Open the hood and allow the engine to cool off a bit. 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.

Now remember this .... if you run the engine and then let it slow down or idle and then check the plugs, you will not get a true indication of the heat!

Of course this is not all 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. Also, a fuel mixture that is too rich or too lean can confuse the readings; plus a poor ignition system, poor compression, an oil burner, etc., etc.; so the accuracy of the above depends on an engine with proper function.

In conclusion, the plugs should run hot enough to keep the deposits burned off and that's it.... This means the color should range anywhere from light brown to grayish tan. Sooty black is too cold and chalky white is too hot.

Larry B.

Re: Would you recommend a hotter plug?
 

No harm meant but I've got to disagree . The W16 Y has a longer tip and may be hotter at 5500 RPM but is colder at lower speeds and runs black and sooty . Anybody that has first run W16 Y and chanbged to W 18 will clearly know this. Larry brumfield made this claim but I don't believe that Champion EVER said that the W16 Y was hotter than the W i8 at lower speeds . Brumfield claimed that A Champion engineer told him ,years ago that trhe W16 Y was hotter. He made this claim on this forum in an argument with me around 2010 and this wrong info has cost a lot of people the price of a set of spark plugs that was way too cold for the way that most model A's are driven . The W16 Y wasn't made to be used with the model A . After the C 16 C plug was discontinued mostr vendors started offering the W16 Y as a lower cost replacement for the 3X plug . Though the W 18 is a little hotter than the 3X the W 18 is closest to the heat of the 3X . I won't argue this fact . This is just my experience . Anybody can believe what they want . I will just say that after a person first tries the W16 Y , they will see what I mean !!!

Re: Would you recommend a hotter plug?
 

I used C16C from 1962 until 1979 when they discontinued them.

All my driving (40,000 miles) was 50 mile minimum round trips at 50 MPH.

Then switched to W16Y that Champion said was same as C16C.

At the same time we moved into town so trips were much shorter and more frequent.

I found the W16Y to be too cold as Purdy said especially after we moved to town.

Never got the chance to run W16Ys on highway for any regularity.

W18s work just fine.

Re: Would you recommend a hotter plug?
 

I agree with Purdy. Here is what I did several years ago. Probably been posted before.

Re: Would you recommend a hotter plug?
 

I've got a handy little cardboard Feb. 1936 Champion Spark Plug Service Type Selector graph/chart. It shows '30, '31 Ford uses 3X with the C4 as the next hotter plug (1st step) & the 3 Com. (2nd step). The O com. is the
only next colder plug.;) I run the W18 Champions, Thank you Mr. Purdy.
Last time I looked my plugs were a light dusty brown color and the car is
running great. I do have the habit of forgetting to readjust my carb. GAV.
Back down once warmed up and driving.:eek::o

Bob-A:D

PS: I'm also running a Pertronix Flamethrower coil.:p

Re: Would you recommend a hotter plug?
 

See here;


http://www.fordgarage.com/pages/brum...kplugnotes.htm

Re: Would you recommend a hotter plug?
 

I found this about plug heat ranges from a manufacturer of spark plugs,


http://www.briskusa.com/spark_plug_c...at_range_chart

Re: Would you recommend a hotter plug?
 

Thanks Mike, good article.