Bosch spark plug heat ranges

[Bob Kelly]

I was going through old set of spark plugs and I have some W200 and W240 Bosch plugs. I think these are different heat ranges but I don't remember which are hotter or colder. Any help?

[James Davies]

W240T1 are for the higher-compression super motors. The W225T1 were for the normals.

[Jacques Lefriant]

Hi
the nos were the time in seconds till preignition based on a special research engine.
j

[Vic Skirmants]

Hi
the nos were the time in seconds till preignition based on a special research engine.
j

Wow! Learn something new every day here.

[Paul Lima]

Another way of looking at it, is that the bigger the number the cooler the plug.

[Dick Weiss]

The -240 was way cold for normal driving and the -225 was used on the S90 during those days; W/today's gas, the common replacement
became the W6BC. If you have fouling problems, the Platinum plug solved that, but further tuning w/the carb adjustments may be needed.

[Jim Perrin]

The January 1956 English edition, the September 1957 English edition, and the “Ausgabe Februar 1959. . . 5.59 G1.” German Edition 356A Owner’s
Manuals all list:
"1600: Bosch W225 T1"
"1600S: Bosch W240 T1"

The September 1959 English 356B owner's manual lists
1600: Bosch W225 T1
1600S: Bosch W240 T1
1600S90: Not listed
The April 1960, print date of 4.61, owner’s manual lists:
1600: Bosch W225 T1
1600S: Bosch W225 T1
1600S90: Not listed
The April 1960 Super 90 Annex to the owner's manual lists the Bosch W225 T1.

[C J Murray]

The January 1956 English edition, the September 1957 English edition, and the “Ausgabe Februar 1959. . . 5.59 G1.” German Edition 356A Owner’s
Manuals all list:
"1600: Bosch W225 T1"
"1600S: Bosch W240 T1"

The September 1959 English 356B owner's manual lists
1600: Bosch W225 T1
1600S: Bosch W240 T1
1600S90: Not listed
The April 1960, print date of 4.61, owner’s manual lists:
1600: Bosch W225 T1
1600S: Bosch W225 T1
1600S90: Not listed
The April 1960 Super 90 Annex to the owner's manual lists the Bosch W225 T1.

Obviously the factory wanted the B Super engines to blow up 15 seconds quicker than the A Supers.

[Bob Kelly]

Thanks, you guys are the best!

[Dick Weiss]

Jim's spark plug listings were correct during those years, but things really changed when the gas changed their formulas due to our speed limit restrictions--no autobahns over here, unless racing--or invisible to the cars w/red & blue lights.
The W6BC was OK for all-around use here and if fouling was due from inaccurate tuning or oil getting past the rings, Platinum plugs would help until a rebuild is scheduled(?).

My $.05