Next to a racer’s bottle of fuel, the glow plug is one of the single biggest factors in the performance of an RC gas-powered vehicle. Knowing the difference between applying a hot plug or a cold plug can make or break your vehicle. Below is a guide to the various glow plugs and a trouble-shooting guide for all RC nitro users.
What are the different plugs on the market?
OS GLOW PLUGS
# 8 Hot Recommended for most current O.S. (and other) 2-stroke engines
Type F Mildly Hot Special long-reach plug recommended exclusively for O.S (and other) 4-stroke engines
Type RE Hot Special long-reach plug designed exclusively for O.S. Wankel rotary engine
A5 Cold Recommended for most current O.S. (and many other) 2-stroke engines particularly for 1/10th & 1/8th scale off-road car engines
A3 Hot Dependable O.S. quality makes A3 the most durable and longest-lasting glow plug available at an economical price
R5 Very Cold Recommended for high-nitro fuel and high r.p.m. engines, particularly 1/8th track racing car engines
FOX GLOW PLUGS
All 1. 5 Volt Plugs are Dry Cell or Ni-Cad
All 2 Volt Plugs are Lead Acid Battery
Standard Short Hot 1.5 Volt, Standard Short Hot 2 Volt
Standard Long Hot 1.5 Volt, Standard Long Hot 2 Volt
Gold STD Long Plug Hot 1.5 Volt, RC Short Mildly Hot 2 Volt
Gold RC Long Hot 1.5 Volt, RC Long Mildly Hot 2 Volt
RC Short Mildly Hot 1.5 Volt
RC Long Mildly Hot 1.5 Volt
Miracle Plug Hot 1.5 Volt
Pro 8 Short Cold 1.5 Volt
Pro 8 Long Cold 1.5 Volt
MCCOY GLOW PLUGS
MC-8 Cold A5, R5
MC-9 Medium Hot #8
MC-50 Hot IDLE BAR – LONG
MC-55 Medium Hot A3, #8
MC-59 Hot
ROSSI GLOW PLUGS
R1 Extra hot 0.8 to 2cc RB4 Hot
R2 Hot from 2 to 3.5cc RB5 Medium
R3 Medium from 3.5 to 6cc RB6 Cold
R4 Cold from 6 to 10cc RB7 Extra cold
R5 X-cold for nitro fuel & R/C RB8 Super cold
R6 Cold nitro 10 to 13cc
R7 Cold for nitro 13 to 15cc
R8 Cold for nitro 15 to 30cc GLOW HEAD FOR R15 G1 Hot
R/C GLOW PLUGS
G2 Medium (with idle bar)
G3 Cold nitro 15 to 30%
RC Hot for 2.5 to 6cc
G4 X-cold nitro 30 to 50%
RC Cold for 6 to 15cc
G5 Cold nitro 50% or more
What are some of the best Hot, Medium, Cold, and Four-stroke glow plugs?
HOT GLOW PLUGS (for low nitro and FAI fuels)
Enya: # 3
Fox: Miracle, Standard, and R/C Long (2V)
Fireball: Hot (1.2-3.0V), and S-20 R/C Long
Fire Power: F 6 (warm), and F 7 (hot)
K&B;: 1 L
McCoy: MC 55 R/C Long, MC 59, and MC 14 (very hot)
O.S. Engines: # 0, # 1, # 5
Rossi: R 1 (extra hot), and R 2
Sonic Tronics: Glowdevil # 300
Thunderbolt: R/C Long
MEDIUM GLOW PLUGS (for 10%-15% nitro fuels)
Enya: # 4 (medium hot), and # 5 (medium cold)
Fireball: Standard (1.2-2.0V)
Fire Power: F 5 (medium), and F 6 (warm)
Fox: R/C Long (1.2-1.5V), and Gold
Hanger 9: Sport Long
McCoy: MC 50, and MC 8
O.S. Engines: # A 3, # 8, # 9, # 7 (with idle bar)
Rossi: Medium, and R-3
Sonic Tronics: Glowdevil Standard
Tower Hobbies: Tower Power Performance plug, and Reg. (w/bar)
COLD GLOW PLUGS (for high nitro; 25% +)
Enya: #6 (cold)
Fireball: Cool (1.2-1.5V)
Fire Power: F 2 (extra cold), F 3 (cold), and F 4 (cool)
Fox: R/C (1.2V)
K&B;: Long & Short high performance nitro plug
O.S. Engines: R-5
Rossi: R 4 (cold), and R 5 (extra cold)
FOUR-STROKE GLOW PLUGS (hot)
Fox: Miracle plug (often used in 2C’s W/low nitro)
McCoy: MC 14 (very hot, often used in inverted 4C’s)
O.S. Engines: Type F
Sonic Tronics: Glowdevil ST 301/302
Can you help me troubleshoot my glow plug issues?
1. If your nitro RC car backfires more than other racer’s nitro car, you may need to either use fuel with less nitromethane or use a colder glow plug
2. Remember that hot plugs are for less than 24% nitromethane fuel and a cold plug is better for more than 25% nitromethane fuel.
3. You need a hotter glow plug if: your engine power is too weak or if it slows down or stops after removing the glow plug battery.
4. You need a colder glow plug if your engine has pre-ignition and loss of power, if the glow plug filament is broke or collapses a lot, or if the overall engine runs rough.
