Norwood Parade Auto Spares
54 the Parade, Norwood, Adelaide,
South Australia 5067
Ph 08 83634183
open 7 days
Home Page www.derek.com.au
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SAT 9.00am - 2.00pm
SUN 10.00am - 2.00pm
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BOSCH Ignition Coils
Hints and tips when replacing Transformer Ignition Coils
For further information on Bosch Ignition Coils please refer
to the Bosch website www.bosch.com.au or contact the
Bosch Customer Service Centre on 1300 30 70 40.
The Bosch transformer ignition coil was introduced to replace the older oil filled coil in 1987 to cater for the rapid development in engine technology, which had led to a higher tension spark being required in new vehicles.
Since its introduction, difficulties and confusion have been experienced by some people when selecting and installing the correct transformer ignition coil to replace the oil filled coil.
Fitting an incorrect coil can result in costly consequential damage to
other parts of the vehicle, such as the ignition module, the Electronic
Control Unit (ECU), the new replacement coil and wiring.
When replacing the oil filled coil with transformer ignition coils, a
number of basic steps need to be followed, and several important factors
needs to be taken into account, before choosing and fitting the replacement
transformer ignition coil.
Determine the reason for the original coil failure
Check that the failed coil was the correct fitment for the vehicle. Test
the wiring and the ballast resistor, if appropriate and determine that the
dwell control is working. The dwell test is essential to ensure that no
damage is caused to the new replacement coil. As a guide, the dwell at idle
speed should be approximately 18 percent and increase to 70 percent at increased
engine speed. The transition should be smooth from idle to approximately
3500 rpm. If the dwell is high at idle and decreasing with increased engine
speed, or remains the same, the ignition module must be replaced. If this
fault is evident, coil primary current will be very high at low engine speeds
and this will overheat the windings.
Always use the Bosch recommended replacement coil
Do not choose a replacement transformer coil just because it has the
same DC resistance as the original oil filled coil. The electrical characteristics
of the transformer coil are vastly different to the oil filled coil for
the same application. The magnetic circuit and the special steel used in
the core construction, along with the windings, determines the overall performance
of the coil. These factors are all taken into
consideration when Bosch
determine a suitable replacement transformer coil. Bosch then back this up with performance testing, using the appropriate distributor and module combination. This process is followed to achieve the results required across the entire operating range of the engine
- Only use Bosch recommended ignition coils with Bosch modules Electronic
ignition coils designed to be used in conjunction with Bosch modules must
not be used with other manufacturers' modules. Bosch modules have current
and dwell control appropriate to a specific Bosch coil. Where Bosch has
undertaken testing on replacement coils for use with -other manufacturers' modules, these will be listed in the Bosch coil catalogue. e.g. Ford Laser, Nissan Bluebird.
- Bosch EK kits must not be used with HEC or MEC ignition coils It is
recommended that ignition coils designed for use with contact sets are not
used with any electronic ignition module;-- as higher than normal back voltage
may damage the switching transistor. Bosch EK kits are designed to operate
with SU12OR and GT4OR ignition coils, along with the original ballast resistor.
Only the original vehicle coil can be used, otherwise the switching transistor
will be destroyed.
Take care when installing ancillary devices
Kill switches or similar devices must not be connected to the negative side of the coil, as the primary of the coil can be overheated. Anti-theft devices must open the positive side of the ignition circuit. If installing ancillary circuitry to the negative side of the coil, only high impedance circuits should be used. Items such as tachometers, cruise controls, speed sensors and warning devices must be investigated before fitment.
Always refer to the Bosch recommendations for each particular vehicle
TRIUMPH IGNITION COILS
The GT40 requires 12 volts on the positive side, whereas the GT40R requires 9 volts which is accomplished by using an inline resistor in the power supply wire to the coil. In some cases the resistance is built into the power supply wire to the coil.
Check the voltage being supplied to your coil.
If it's 9 volts, use the GT40R.
If it's 12 volts, use the GT40.
From the factory, they use 9 volts to run the coil, and in order to help start the car, there is a wire from the starter motor which supplies 12 volts when you crank the engine over so the coil gives a much bigger spark. To test this, measure the voltage at the coil during engine cranking. If all is standard, you should have 9 volts when the ignition is turned on, and 12 during cranking.
If you supply 12 volts to a GT40R, the coil won't last too long. If you supply 9 volts to a GT40, then you are going to get a very poor spark.
BELOW IS A DIAGRAM OF THE BALLAST IGNITION WIRING LAYOUT
4WD COVERS AH GO GAH HORN AIR FILTERS AIR HORNS ARMREST ASHTRAYS AUTO ACCESSORIES AUTO DRY WASH CLOTHS BABY BOLTS BACK SUPPORTS BADGES BATTERY CHARGERS BATTERY ISOLATOR SWITCH BLIND SPOT MIRRORS BOAT POLISH BOAT WASH BOAT WAX BODY FILLERS BOG BRAKE LIGHT REPAIR KIT BRAKE SHOES BUG SCREENS BULBS BUMPER SPRAY CABLE TIES CAR BATTERIES CAR COVER CAR MATS CAR STANDS CARAVAN COVERS CENTRE CONSOLES CHARGE AND MAINTAIN CHEMICALS CHEMIWELD COMPRESSION TESTER COOLANTS COOLING FANS CUT AND SHAPE MIRROR D SHACKLES DEGREASERS DISC PADS DISC PADS DOOR EDGE PROTECTORS DRI-LUBE DRIVE BELTS DRIVE SHAFTS DRIVING LIGHTS ELECTRIC WATER PUMPS ELECTRICAL TAPE ELECTRONIC IGNITION ENGINE PUMPS EXHAUST CLAMPS FAN BELTS FIBERGLASS FISHING ROD HOLDERS FOOT PUMPS FUEL CANS FUEL FILTERS FUEL HOSE GASKETS GLOSS BLACK GOGGLES H4 LIGHTS H7 LAMPS HAND PUMPS HEATER HOSES HELLA LAMPS HOSE CLAMPS HOUSINGS HYDRAULIC JACKS IGNITION COILS IGNITION LEADS INDUSTRIAL BELTS JACKS JOCKEY WHEELS JUMPER LEADS KEY FOBS L PLATES LEAD REPLACEMENT ADDATIVE LED HEADLAMPS LED LIGHTS LED TORCHES LENS REPAIR KITS LENS TINT LITTER BINS MAG WHEEL CLEANERS MASKING TAPE MASKS MATT BLACK MICRO CHAMOIS MICRO FIBRE CLOTHS MIRRORS MOTHER'S WAX ATTACK POLISHER MOTHERS WAX ATTACK POLISHER MOTOR BIKE STRAPS MUSICAL AIR HORN NAVIGATION LIGHTS NECK SUPPORTS NOLTEC SOFTRIDE URETHANE BUSHES OCCY STRAPS OIL CAPS OIL FILTERS P PLATES PAINT PAINT PETROL CAPS PHILLIPS LAMPS PLASTIC CHAMOIS PLASTIC DYE PLUGS POLISHES POLSHING CLOTHS PROJECTA RACK ENDS RADIATOR CAPS RADIATOR HOSES RECOVERY STRAPS RED BACK SPIDER GEAR KNOBS ROK STRAPS ROOF BARS ROOF BASKETS ROOF RACKS SEAT BELTS SEAT COVERS SLICK50 SLICK 50 SNATCH STRAPS SOLAR PANELS SPANNERS SPARE WHEEL COVERS STAINLESS STEEL BOLTS STEERING WHEEL COVERS SURGE GUARDS SWITCHES SYNTHETIC CHAMOIS SYNTHETIC OILS THERMOSTATS THINNERS TIE ROD ENDS TIMING BELTS TIMING LIGHTS TOOLS TOOLS TOP COAT CLEAR TOW HOOKS TOW ROPES TRAILER CABLE TRAILER LAMPS TRIPLE AIR HORNS TROLLEY JACKS TRUCK HOSES TRUCK WASH TUBE PATCHES TUBELESS TYRE REPAIR KITS TRUCK JUMPER LEADS TWIN AIR HORNS TYRE SPRAY TYRE VALVES UNIVERSAL JOINTS UTE HOOKS VACUMN TESTER WALL PROTECTORS WASHER MOTORS WATER HOSE WATER PUMPS WATERPROOF TRAILER LAMPS WHEEL BRACES WHEEL CHOCKS WHEEL CYLINDERS WINDOW SHADES WINDOW SOX WINDSCREEN WIPERS WIPER ARMS WIPER BLADES WIPER JETS WIPER MOTORS WIPER REFILLS