924 Garage & Register "...the best handling Porsche in stock form", J Pasha, Excellence

Bosche Spark Plugs

The 924 uses the 14mm thread.

Bosch Spark Plug Numbering System, reading from left to right:

Thread size
D 18mm tapered seat
F 14mm 5/8 hex
H 14mm tapered seat
M 18mm tapered seat
U 10mm
W 14mm
X 12mm 11/16 hex
Y 12mm 5/8 hex

Heat Range
E Surface Gap
R Resistor Suppressor
S Mini Plug

Thread Reach
A .460. Std. Electrode
B .460. Extended Tip
C 3/4" Std. Electrode
D 3/4" .708 tapered seat extended tip
E 3/8" Regular Electrode
F 3/8" Extended Tip
G .460 Extra Extended Tip
H 3/4"
H0 .840 Tapered Seat Special Extended Seat Full Thread
L 3/4" .708 with Tapered Seat Extra Extended Tip
L0 .840 Tapered Seat Special Tip Half Thread

C Copper Core Center Electrode
D 2 Ground Electrode
P Platinum Electrode
R Burnoff Resistor
S Silver Electrode
T 3 Ground Electrodes
X Wide Gap .044 (1.3mm)
Y Wide Gap .060 (1.5mm)
Z Wide Gap .080 (2.0mm)