Spark Plug Reading
 

Greetings Barn - can you read this plug for me? I have a stock ‘51 F1 8ba w/2bbl 94 carb. I removed this plug today after a 30 mile 50-55mph road trip. Truck ran great with no issues. Plugs are NGK’s 6BL. Jets are .51 (if I recall correctly). It appears to read a rich fuel mixture to me. Anyone else have a plug look like this and what step corrected it?

Attachment 445253

Re: Spark Plug Reading
 

Looks like yours is 'Carbon Fouled' - as seen in the chart below....

http://gtsparkplugs.com/reading-spark-plug-color.html
http://www.gtsparkplugs.com/images/A...ading-800x.jpg
http://2.bp.blogspot.com/-2QNSu1Zq1L...tion-chart.jpg

Re: Spark Plug Reading
 

Is this indicitive of all plugs? The plugs seem 'normal ' heat range and your Holley 94 seems to have the standard 51 jets for sea level area. hows the power valve size?
how does it run at idle. Is the air cleaner clear.
as stated it shows carbon fouled, does it use any oil.
The porcelain looks the right colour, tan coloured.
Verify if all plugs are this condition before any 'fine tuning"
Phil NZ

Re: Spark Plug Reading
 

:eek: That plug looks like its been in there for three months. Its hard to read plugs like the old days, fuel is different and probably varies from country to country, Definitely dark for such a short trip .

Re: Spark Plug Reading
 

Good point Talkwrench - yes, they’ve been in about 300 miles ... I only just checked them after this trip. All my trips are at least 30 miles and mostly at 50-60mph. Very little stop and go. I pulled 1 from each side and they both looked about the same. I’ll pull them all, clean ‘em up and then re check after 100 miles. I’ll also recheck the gap and timing. Standard California unleaded gas ... no visible smoke but does use a bit of oil over time. Original oil filled air filter.
Good feedback everyone thanks.

Re: Spark Plug Reading
 

The best way to get a reading is to run at speed for a period of time then shut off vehicle and coast to a convenient spot and pull the plugs.

Re: Spark Plug Reading
 

Mine were carboned up like yours. I removed the small air cleaner elements that were restricting the flow. It also appeared there was not enough clearance between the aircleaner base and cover so I drilled holes in the base for more air flow and left the filters out.

Installed Pertronix ignition and retimed with a light and vacuum gauge. It now runs a little lean. I need to bump up the jet size.

Re: Spark Plug Reading
 

You think the original style (oil filled) air filter could be a contributing factor? Should I exchange it for a paper one?

Re: Spark Plug Reading
 

Try taking it off and on and see if there is a noticable difference. Shortest path to a solution would be using an A/F ratio meter.

Re: Spark Plug Reading
 

The small 4inch paper ones were giving me trouble. Your Oil bath should be alright. Like JSeery said try it without.
Check the choke plate, make sure it opens all the way.

Re: Spark Plug Reading
 

Do a search on Holley 94 power valves


I'm running the 4-BL which are one step hotter then yours.