SEAL-ON™ SPARK PLUG BOOTS
BG’s Seal-On™ Boots prolong spark plug life because they seal out dirt and moisture…
Engine laboratory tests have shown that when the Seal-On™ Boot is used, flashover voltage is increased by 8-10KV. Unlike conventional spark plug boots, the BG Seal-On™ Boot is machined from PTFE to specific spark plug dimensions and seals tightly on the spark plug insulator. The boot design incorporates an industry standard type bayonet connector for ease of installation. The kit includes a PTFE grommet that is press fit into the upper end of the assembly so that the boot is sealed top and bottom – at the secondary lead and at the plug insulator. Kits are also available for use with “hi-resistance” wire, which include the stud and stud support required to terminate this type of wire (Assembly layout shown on page 41). Optional Seal-On™ Boot kits are also available for applications where 5/16” ID silicone hose is used. Available with DSTM connector.**
Improves ignition performance in demanding lean burn applications


SEAL-ON BOOT KIT PART NUMBERS | LOCATE THE SPARK PLUG USED IN THE CHART BELOW AND ORDER THE CORRESPONDING SEAL-ON BOOT KIT. | |||
For 7mm Cable With Hi-Resistance Conductor | For 7mm Cable With Standard Conductor ++ | |||
Without Hose | With Hose | Without Hose | With Hose | |
21509SS | 21644SS | 21509* | 21644* | RM79F, W77N, RW82P, RM77N, D78Y, RB77WPC, All Unshielded Altronic, RS79N, RB777-X, GI3-X, etc. |
21519SS | 21573SS | 21519 | 21573 | RN79G, J6C, RL85G, RL15B, F100, N5C, 42XL, ST447, L82C, W3DPOR, GE3-X, etc. |
21539SS | 21645SS | 21539 | 21645 | W80N, W85N, D9, D15Y, RD16, D14N, D6, D14, RD10, *** |
21594SS | 21648SS | 21594 | 21648 | W14, W18, W10 |
21673SS | 21676SS | 21673 | 21676 | RW80N, RW83F, RW77N, RW78N |
21970SS | 21984SS | 21970+ | 21984+# | RC501P, RC78PYP, GK3-X |
21894SS | 21898SS | 21894 | 21898 | RB212-1, RB485-1 |
22448SS | 22449SS | 22448 | 22449 | RB105-1, RB114-1 |
21862SS | — | 21862 | 22857 | ST197 |
21892SS | 21896SS | 21892 | 21896 | ST847 |
21893SS | 21897SS | 21893 | 21897 | ST727 |
22026SS | 22027SS | 22026 | 22027 | R80 |
* This model available in 9″ length. Specify -9 suffix (i.e., 21509-9).
** For DS™ type connector, specify kit model number with SS suffix.
*** These kits will also “seal-on” on Flash-Fighters shown on Page 11.
+ These models available in 4 1/2″ lengths. Specify -4.5 suffix (i.e., 21970-4.5).
++ The kits shown in the columns below may be upgraded to Spike DS™ by ordering P/N 22390.
# This model available in 10″ length. Specify 25189.