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Typically the heat range for NGK Spark Plugs varies from 2-11. This number indicates the thermal characteristics of a spark plug, or how ‘hot’ or ‘cold’ a spark plug is. The term hot/cold is commonly used to describe whether a spark plug heats up easily (hot) or whether it provides resistance to heating up (cold).

Generally, low power engines such as lawn mowers don’t produce a large amount of heat, hence use a low heat range (or hot) spark plug such as a 4 heat range. This means the spark plug will heat up easily and reach its optimal operating temperature. High performance engines on the other hand produce a large amount of heat, hence a high heat range (or cold) spark plug such as a 10 heat range needs to be used to resist the heat developed by the engine.

Several factors influence the heat range of a spark plug, although typically the insulator nose design provides an indication of the heat range of a spark plug.

When a spark plug absorbs heat produced from combustion, the heat is transferred through the centre electrode and insulator nose to the metal shell, which then transfers the heat into the engine casing and circulating coolant.
A low heat range (or hot) spark plug typically has a long thin insulator nose which will heat up easily however will not dissipate readily to the metal shell. Conversely, a high heat range (or cold) spark plug has a short thick insulator nose which will dissipate heat much easier).

NGK has discontinued manufacturing of all non-resister plugs. All NGK spark plugs sold are now resister type.
Classic Mini NGK spark plug (various heat ranges)

Classic Mini NGK spark plug (various heat ranges)

Classic Mini NGK spark plug (various heat ranges)

Classic Mini NGK spark plug (various heat ranges)

Classic Mini NGK spark plug (various heat ranges)
Stock spark plugs for use with alloy 7 port cylinder head. This is an 8mm spark plug.
The BP7ES plug is for higher compression engine that should have a colder spark plug. The engineers explain that it has to do with flame temperature and overheating the plug. I know from experience that my race engine will melt a street plug! Choose from the following NGK plugs:
Cold Street=BP7ES
Colder Street=BP8ES
Cold Race=BP9EV
Coldest Race=BP10EV
Very cold running spark plug that is often used in racing applications
These NGK spark plugs are just the thing for A-Series race engines. They're very cold, for use with 12:1 & up compression, and feature NGK's special gold palladium fine tipped electrode.

NGK Standard Types Spark Plugs

Copper core NGK spark plug with recessed nose for high compression engines.

NGK Standard Types Spark Plugs BP10EV
Design Symbols used in NGK Spark Plugs
B - Thread Size / Hex Size: 14 mm / 13/16" (20.8 mm)

P - Construction: Projected Insulator Type

Heat Rating Numbers : 10

E - Firing End Construction: V-Grooved Center Electrode (14 mm only) 1/5 mm Insulator

V - Firing End Construction: Fine Wire Gold Palladium Center Electrode

GK Standard Types Spark Plugs BP10EV
Design Symbols used in NGK Spark Plugs
B - Thread Size / Hex Size: 14 mm / 13/16" (20.8 mm)

P - Construction: Projected Insulator Type

Heat Rating Numbers : 10

E - Firing End Construction: V-Grooved Center Electrode (14 mm only) 1/5 mm Insulator

V - Firing End Construction: Fine Wire Gold Palladium Center Electrode

A standard NGK plug
This is the NGK spark plug that not only has a wide range of applications, 850cc to 1275cc+, but also a very wide heat range. This is an ideal plug for all street applications. also fits the Sprite, MG Midget , and Morris Minor. Resistor spark plugs prevent electrical interference that can disrupt car radio reception, two-way radio and cellular phone operation. This type of spark plug also prevents electrical noise from interfering with the operation of the computer in the engine. Specs below:

Torque Specs: Cast Iron: 18-25.3 lb. ft. Aluminum: 18-21.6 lb. ft.

  • Trivalent metal plating provides superior anti-corrosion and anti-seizing properties
  • Corrugated ribs prevent flashover
  • Pure alumina silicate ceramic insulator, provides superior strength and better heat transfer
  • Copper core aids in heat removal
  • Triple seals prevent leakage

Shell

  • Thread Size: 14mm
  • Thread Pitch: 1.25mm
  • Seat Type: Gasket
  • Resistor Value: 5K Ohm
  • Reach: 19mm (3/4")
  • Hex Size: 13/16" (21mm)
  • Terminal Type: Removable Nut
  • Overall Height: JIS
  • Gap: .035" (0.9mm)
These NGK spark plugs are just the thing for A-Series race engines. They're very cold, for use with 12:1 & up compression, and feature NGK's special gold palladium fine tipped electrode.

Typically the heat range for NGK Spark Plugs varies from 2-11. This number indicates the thermal characteristics of a spark plug, or how ‘hot’ or ‘cold’ a spark plug is. The term hot/cold is commonly used to describe whether a spark plug heats up easily (hot) or whether it provides resistance to heating up (cold).

Generally, low power engines such as lawn mowers don’t produce a large amount of heat, hence use a low heat range (or hot) spark plug such as a 4 heat range. This means the spark plug will heat up easily and reach its optimal operating temperature. High performance engines on the other hand produce a large amount of heat, hence a high heat range (or cold) spark plug such as a 10 heat range needs to be used to resist the heat developed by the engine.

Several factors influence the heat range of a spark plug, although typically the insulator nose design provides an indication of the heat range of a spark plug.

When a spark plug absorbs heat produced from combustion, the heat is transferred through the centre electrode and insulator nose to the metal shell, which then transfers the heat into the engine casing and circulating coolant.
A low heat range (or hot) spark plug typically has a long thin insulator nose which will heat up easily however will not dissipate readily to the metal shell. Conversely, a high heat range (or cold) spark plug has a short thick insulator nose which will dissipate heat much easier).

 
 
Question:
hi I had a 1993 mini rover engine 1,3i automatic. what kind of spark plug do i need to buy thank
Answer:
Hello,
 
You will want to use BPR6ES.

Mini Mania Tech Support
 
 
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