RICHARDSON ENGINEERING AND MACHINING
Whether you are going for the Full Pull, restoring that antique tractor or just want a set of long-life platinum plugs for that everyday workhorse, sparkplug adapters allow you to choose the right plug for the job!

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Click "INFORMATION" tab for tractor application guide.
 
 
 
 
Products
1/2" NPT x 14mm Sparkplug Adapter
- 7/8" Hex Diameter
- 1/2" NPT PipeThread Diameter (Outside)
- 14mm Thread (Inside)
- Fits most engines built before 1925
 
SparkPlug Adapters
3/4" NPT x 14mm Sparkplug Adapter
- 1" Hex Diameter
- 3/4" NPT Pipe Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits some engines built before 1925
7/8" Flat Seat x 14mm Tapered Seat Sparkplug Adapter
- 1" Hex Diameter
- 7/8" Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits most engines built between 1925-1939
18mm Flat Seat x 14mm Tapered Seat Sparkplug Adapter
- 7/8" Hex Diameter
- 18mm Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits most engines built between 1939-1970
18mm Flat Seat Extended x 14mm Tapered Seat Sparkplug Adapter
- 7/8" Hex Diameter
- 18mm Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits Allison V12 Engine
18mm Tapered Seat x 14mm Tapered Seat Sparkplug Adapter
- 7/8" Hex Diameter
- 18mm Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits Ford Y-Block V8
14mm Tapered Seat Brass Sleeve
- The Brass Sleeve is used in tractors where the thread length is less than 1/2" long. It allows the use of a 14mm tapered seat platinum plug with a 3/4" thread length to be used in Ford N series and Allis Chalmer tractors.   
18mm Flat Seat Gas Flare x 14mm Flat Seat Sparkplug Adapter
- 7/8" Hex Diameter
- 18mm Thread Diameter (Outside)
- 14mm Thread (Inside)
- Fits Continental Engines & Special  Applications