Spark plug conversion table
Spark Plug List
Application notes provided by Don Roubos
| Application | New Champion | Old Champion | A–C | Auto Lite |
| 4-cyl | C-26(c) | C-4 |
76-S(7/8"Hex) 78-S(1 1/8" Hex) |
The heat range is not as important an issue as the fact of about 1/2" of metal reaches below the end of the threads. The DB's combustion chamber is configured such, that the spark plugs are up in a recess, and a 'normal' plug will carbon up after the first tour. A longer plug gets the spark closer to the actual combustion area.
Roger "Dodger" Hartley
7/8" spark plugs cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| W-10 | 0 Com | 73 Com | ||
| W-14 | 1 Com | 74 Com | T-7 | |
| 6-cyl Victory & Senior thru 1928 | W-18 (#518) | 2 Com | C 77L | T-9 |
| W-20 | 3 Com or No 20 | 78 Com | T-11 | |
| W-89D | 44 | 18 | 3077 | |
| W-85N | 901 | |||
| W-95D | 45 |
The bottom three plugs are special extension models Recommended torque for a cast iron head is 37 lb-ft 35 lb-ft for aluminum 10 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| UY-6 | Y-4A | 104 | P-4 | |
| UY-6 | Y-6 | 106 | ||
| UY-6 | Y-8 | 108 | P-6 |
Recommended torque for cast iron head is 14 lb-ft 12 lb-ft for aluminum 14 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| J-57-R | J-2 | 42 | A3 | |
| H-8 | H-9 | 43L | A5 | |
| 1932-1942 Aluminum head | CJ-8 (#841) | J-8 | 45 | A7 |
| UJ-12 | J-12 | 47 | A11 |
Recommended torque is 30 lb-ft for cast iron heads 28 lb-ft for aluminum 18 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| D-6 | 4 Com | 82S | ||
| D-9 | 5 Com | 83-S | B5 | |
| D-14 | 6 Com | 84 | B7 | |
| 1929 6cyl 1930-31 6 & 8 cyl | D-16 (#516) | 7 | 85-S | |
| 1929 6cyl 1930-31 6 & 8 cyl | D-16 (#516) | 8 Com | 86 | B9 |
| D-21 | C-15 | 87 | B11 | |
| D-23 | 10 Com | 88-L | 388 | |
| D-89D | 49 | 18A |
The bottom plug is a special extension model Recommended torque for cast iron is 34 lb-ft 32 lb-ft for aluminum heads For 1/2" pipe plugs recommended torque in cast iron is 35 lb-ft All values are for clean lubricate threads. Over tightening a plug with a .025 gap the gap will increase to .031. Created from a 1947 heat range list and current Champion list.
Spark plug conversion table
Spark Plug List
Application notes provided by Don Roubos
| Application | New Champion | Old Champion | A–C | Auto Lite |
| 4-cyl | C-26(c) | C-4 |
76-S(7/8"Hex) 78-S(1 1/8" Hex) |
The heat range is not as important an issue as the fact of about 1/2" of metal reaches below the end of the threads. The DB's combustion chamber is configured such, that the spark plugs are up in a recess, and a 'normal' plug will carbon up after the first tour. A longer plug gets the spark closer to the actual combustion area.
Roger "Dodger" Hartley
7/8" spark plugs cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| W-10 | 0 Com | 73 Com | ||
| W-14 | 1 Com | 74 Com | T-7 | |
| 6-cyl Victory & Senior thru 1928 | W-18 (#518) | 2 Com | C 77L | T-9 |
| W-20 | 3 Com or No 20 | 78 Com | T-11 | |
| W-89D | 44 | 18 | 3077 | |
| W-85N | 901 | |||
| W-95D | 45 |
The bottom three plugs are special extension models Recommended torque for a cast iron head is 37 lb-ft 35 lb-ft for aluminum 10 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| UY-6 | Y-4A | 104 | P-4 | |
| UY-6 | Y-6 | 106 | ||
| UY-6 | Y-8 | 108 | P-6 |
Recommended torque for cast iron head is 14 lb-ft 12 lb-ft for aluminum 14 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| J-57-R | J-2 | 42 | A3 | |
| H-8 | H-9 | 43L | A5 | |
| 1932-1942 Aluminum head | CJ-8 (#841) | J-8 | 45 | A7 |
| UJ-12 | J-12 | 47 | A11 |
Recommended torque is 30 lb-ft for cast iron heads 28 lb-ft for aluminum 18 mm cold down to hot
| Application | New Champion | Old Champion | A–C | Auto Lite |
| D-6 | 4 Com | 82S | ||
| D-9 | 5 Com | 83-S | B5 | |
| D-14 | 6 Com | 84 | B7 | |
| 1929 6cyl 1930-31 6 & 8 cyl | D-16 (#516) | 7 | 85-S | |
| 1929 6cyl 1930-31 6 & 8 cyl | D-16 (#516) | 8 Com | 86 | B9 |
| D-21 | C-15 | 87 | B11 | |
| D-23 | 10 Com | 88-L | 388 | |
| D-89D | 49 | 18A |
The bottom plug is a special extension model Recommended torque for cast iron is 34 lb-ft 32 lb-ft for aluminum heads For 1/2" pipe plugs recommended torque in cast iron is 35 lb-ft All values are for clean lubricate threads. Over tightening a plug with a .025 gap the gap will increase to .031. Created from a 1947 heat range list and current Champion list.