STITT · STITT S-R107-2 Spark Plug. Schematic of Ceramic Insulator Construction Terminal Post / Center Insulator Conducting Rod High Temperature Copper and Borosilicate

STITTSpark Plug Company

STITTSpark Plug Company

®®

Conroe, TexasPhone: 936-756-7796 • 281-443-2279

Outside Texas: 800-231-8006Fax: 936-539-9762

www.stitt-sparkplug.c [email protected] om

IgnitionControlModule

(Magneto )

IgnitionStep-Up

(Transformer)Coil

Lower VoltagePrim ary Wiring330 - 380 Volts

Highe r VoltageSecondary Wiring>1000 Volts - Open

Circ uit Voltage(Nominal 38,000)

Basic Ign ition Circuit

STITT S-R107-2 Spark Plug

Schematic ofCeramic Insulator

Construction

Terminal Po st / Center Ins ulatorConduc ting Ro d

High T emperature Copper and Bo rosilic ateGlass Non-Resistor or Bo rosilic ate Glass

and Resistor Sealing Mat erial

Nickel Center Electrode and SteelLocking N ut

High T emperature High Die lectricAlum ina Oxide Insulator

Electrical“Feed Through”

High TemperatureGas-Tight Seal Zones”

B

B

CA

A. Center Ins ulator Bo re SealB. Bottom Internal S eat Gasket / Steel Shell To Insulator Seal Gasket

C. Folded Steel External S eat Gasket

CompletedSpark PlugSchematic

Termi nal Nut

Internal Rod

Ceramic Ins ulator

Safety Restraint

Steel Shell

Copper Glass or Resistor Bore Seal

Steel Nut

Cent er Electrode

Shell To Insulator Seal Gasket

Ground Ele ctrodes

Bottom Internal Seat Gasket

Material

Nic

kel 2

11

Silv

er

Pal

ladi

um

Pla

tinum

Nic

kel

Iro

n

Gol

d

Co

pper

Gol

d -

Pal

ladi

um

Allo

y 80

0 (F

E-N

I-C

R)

SA

E 1

117

Ste

el

304

Sta

inle

ss S

teel

Gra

y C

ast I

ron

Alu

min

um A

lloy

390

Tun

gst

en

Irid

ium

Rat

e O

f T

rans

fer

(W

/m•K

)450

400

350

300

250

200

150

0

100

50

Fastest

Slowest

Comparison Of Material The rmal Tra nsfer Rates

5R

4R

3R

2R

1R

5L

4L

3L

2L

1L

.015" = 15 kv300 microseconds

.020" =

.025" =

20 kv200 microseconds

25 kv100 microseconds

Voltage Requiremen ts

(Appro ximate Values)

Spark Plug Life in High Excess Air / Long SparkDuration, Low NOx, Low CO Ignition

(22 - 45 Crank Angles)

Nickel Ground ElectrodesNickel Center Electrodes

.034 sq. inches of Spark Gap Surface Area

500 - 800 hrs..015" - .050"

Nickel Ground ElectrodesAuPd Center Electrodes

.020 sq. inches of Spark Gap Surface Area

1500 - 2000 hrs..015" - .050"

AuPd Ground ElectrodesAuPd Center Electrodes

.020 sq. inches of Spark Gap Surface Area

6000+ hrs..015" - .025"

1L2262Hrs.Yes

2L3262Hrs.No

3L2862Hrs.Yes

3L-B400Hrs.No

4LUnknown

Hrs.Yes

5LUnknown

Hrs.Yes

6L3262Hrs.No

1R3262Hrs.No

2R3262Hrs.No

3R3262Hrs.Yes

4RUnknown

Hrs.Yes

5R2750Hrs.Yes

5R-B512Hrs.No

6R3262Hrs.No

CYL 3LJET CELL

2,862 RUN HOURS

CYL 5RJET CELL

2,750 RUN HOURS

CYL 3LJET CELL

2,862 RUN HOURS

CYL 3LScanning Electron Micrograph

100x

CYL 3LScanning Electron Micrograph

250x

CYL 3L -BJET CELL

400 RUN HOURS

CYL 5RJET CELL

2,750 RUN HOURS

CYL 5RScanning Electron Micrograph

20x

CYL 5RScanning Electron Micrograph

250x

CYL 5RMetallograph

100x

CYL 5RMetallograph

100x

CYL 5R - BJET CELL

512 RUN HOURS

Low Seat Spark Plu g“Cold Heat Ran ge”

High Seat Spark Pl ug“Hot He at Range”

Over Torqu ed

Shell StretchedAway From Internal

Seat Gasket CausingLeakage.

Normal Torqu e

Shell Torque dProperly . Seat Gasket

Remains Tight .No Leakage.

IgnitionControlModule

(Magneto )

IgnitionStep-Up

(Transformer)Coil

Lower VoltagePrim ary Wiring330 - 380 Volts

Highe r VoltageSecondary Wiring>1000 Volts - Open

Circ uit Voltage(Nominal 38,000)

Basic Ign ition Circuit

STITT S-R107-2 Spark Plug

RFI Spectrum A nalys isHigh Ohm ic Value Spark Plugs With Regular S park Plugs

60

50

40

30

20

10

0

bB (

uV/m

)

30 40 50 60 70 80 90 100

200

300

400

500

600

700

800

900

1000

Engine Operating Wit h 827’s 01/30/86

Engine Operating Wit h U827’s 02/24/86

Frequency (MHz)

RFI Spectrum A nalys isAmbient RFI Noise Levels

60

50

40

30

20

10

0

bB (

uV/m

)

30 40 50 60 70 80 90 100

200

300

400

500

600

700

800

900

1000

Ambient RFI Engine Not Operating 01/03/86

Engine Operating Wit h U827’s 02/24/86

Frequency (MHz)

ChampionOld RW80N

Post - 1975RW80N

ChampionOld RW83F

Post -1975RW83F

Safety Restraint

Restraint Welded to Shell