I can’t thank you all enough for joining us during our seminar at the GOF-South. We always enjoy chatting with all of you and seeing your cars. If you have any questions about the material we’ve covered today, please feel free to reach us at info@ceresmotorsports.com
Upgrading your electrical system can help reduce strain on your electrical system, eliminate maintenance items, and improve drivability. We’ll be reviewing some of our favorite upgrades as well as pointers for general electrical repairs and maintenance.
ALTERNATORS
In early MG’s, original generators produce approximately 22 amps while most “alternator-in-generator” upgrades will provide around 45. Our friends at BP Northwest provide alternators in generator housings for TD’s, TF’s and MGA’s that match the original generator style and even come with tach drives if needed. They look completely stock and are essentially a “bolt on” upgrade with only a minor wiring change to bypass the voltage regulator, which means you’ll never have to worry about whether your alternator is under-charging (or overcharging!).
MG TC (C45 style):
http://gener-nator.com/
MG TD/TF (C39/C40 style):
Negative ground: https://www.bpnorthwest.com/mg/mg-tc-td-tf/engine-electrical/alternator-generator-c39-c40-style-with-tach-drive-negative-ground.html
Positive ground: https://www.bpnorthwest.com/mg/mg-tc-td-tf/engine-electrical/alternator-generator-c39-c40-style-with-tach-drive-positive-ground.html
MGA:
https://www.bpnorthwest.com/mg/mga/engine-electrical/alternator-generator-conversion-mga.html
MGB:
Standard Lucas alternators for MGB’s only output between 34 and 45 amps but we find MGB’s typically get loaded with a lot more accessories too. It’s common to find owners adding phone chargers, cd players/radios, amplifiers, cooling fans, navigation units, air conditioning, etc. Our favorite upgrade is a Delco/Saturn alternator.
Alternator: Bosch AL8596N
Pigtail connector: Dorman 85854
Pulley: Powermaster 118
Delco/Saturn alternators do require some modification to fit. The instructions to add this alternator to your MGB can be found from the MG Club of Toronto.
https://mgtoronto.com/wp-content/uploads/2021/04/Alternative_Alternators.pdf
POSITIVE TO NEGATIVE GROUND
This is a quick note but we really encourage a lot of our customers to convert to negative ground. We find that a lot of people are perplexed by positive ground wiring and that’s completely understandable. At this point, practically every car is wired using negative ground. It’s a very discreet modification and makes your car easier to upgrade with accessories.
DISTRIBUTOR, COIL, ETC
Switching your ignition from a points distributor to electronic ignition eliminates another maintenance item. Worn distributors benefit greatly from electronic ignition because the modules are not sensitive to wear in the cam or the cam lobes.
Entire distributors can be purchased with electronic ignition modules too. They’re available from Pertronix, Accuspark, 123Ingition, and more.
It’s important to make sure that your coil has the proper resistance for the electronic ignition system. Too little resistance will burn up the module internally so make sure to reference the installation instructions to verify you have the proper ohm rating.
LED LIGHTING
LED lighting has become A LOT more popular in the last few years. LED’s draw a fraction of the current of an incandescent bulb and they provide much greater light output. If your car has been converted to negative ground, adding LED’s is a breeze.
We typically like to use universal 7” headlamps (Valeo Cibie’s or Hella’s) and fit H4 LED’s in the housing. The light pattern is still crisp with very good projection and the cars end up looking stock otherwise. We recommend using a passively cooled headlamp LED with a heatsink or straps that provides high light output but doesn’t require a fan to cool itself. They’re easier to fit inside the headlamp buckets of our MG’s and you don’t have to worry about fan failures or overheating bulbs.
It’s worth noting that LED lighting is that white LED’s come in different shades that vary between warm and cool color temperatures. Warm lighting looks similar to the original incandescent lighting while cool lighting looks like a modern blueish white. The color temperatures are rated on a kelvin scale. 3000k is a warm white while 6000k is little blueish.
You can see the differences in lighting here: https://www.ledlightingwholesaleinc.com/v/vspfiles/images/Kalvin%20Color.jpg
If you convert your brake lights to LED’s make sure that the visible difference between the running light and the brake light is noticeable for drivers behind you. I’ve seen cheap amazon bulbs that hardly have a difference in light output between the two. If people can’t tell when you’re braking, you’ve effectively made the care MORE dangerous.
We’re big fans of MAXGTRS’ 1157 bulbs for brake lights. They use high output Cree LED’s and are drop in replacements for incandescent bulbs. They can be found on Amazon: https://www.amazon.com/MAXGTRS-BAY15D-Signal-Condenser-Reverse/dp/B07KZMSN6Q/ref=cm_cr_arp_d_product_top?ie=UTF8
Tips for exterior lights:
Use bulbs that match the lens color. If you have a brake lens or side marker light that’s red, use a red LED. If you have amber turn signal lenses, use amber LED’s. The reason this is important is because white LED’s will make the lens color look washed out and pale.
RELAYS
If you’re not inclined to use LED’s in your headlights, installing relays are a fantastic way to improve incandescent lighting. With original wiring, power is run through the headlight switches. We’ve seen a lot of voltage drop at the headlights as well as burned up switches. When you install relays, the switch will trigger the relay but the power will be pulled directly from the alternator or battery.
Moss sells a great relay kit that matches the lucas wiring colors here: https://mossmotors.com/headlight-relay-kit
COOLING FANS
This portion is almost entirely for the late model MGB owners with the push fans. When the cooling systems are in perfect working order, the push fans don’t struggle with cooling the radiator. However, some of the fan motors we’ve seen need rebuilding/replacing. They draw a ton of current and don’t spin as well as they should, leading to high coolant temps and overheating.
Replacing the push fans with a puller fan is an easy upgrade if your original fans seem to not be cutting it. Moss Motors sells fan kits from Revotec and Hayden. Amazon has plenty of universal fan options available too. These puller fans can easily be added in place if the push fans for more effective cooling. Keep in mind that the fans will only draw air through the surface area that the fan covers so getting the largest size your radiator can take is important.
REPAIRS:
BATTERY CONNECTIONS & GROUND STRAPS
Clean, tight battery connections are a must. We also highly recommend making sure your battery cables are proper colors (no red ground cables!) as well as installing colored felt washers. They prevent corrosion and clearly indicate the terminals. Make sure your battery grounds and engine grounds are secured to clean metal. Use a thin layer of dielectric grease to prevent corrosion.
CONNECTORS
Make sure if your harness has spade connectors, ring/fork terminals, or butt splice crimps that the crimps are tight and the connections are secure. It’s not uncommon to find connectors that are crimped to the wire insulation instead of the wire. Also, make sure the connector is the proper size for the gauge of wire. Generally, red connectors will fit 22 to 18 gauge wire, blue will fit 16 to 14 gauge wire, and yellow will fit 12 to 10 gauge wire. If you tug on the wire and the connector slips off, you may have the wrong size connector or the crimp was bad.
Do not use wire nuts. Do not use solid core wire. Do not twist and tape wires together. Make sure solder joints are secure. Use heatshrink or electrical tape to insulate any exposed wiring or connectors.
MODIFIED WIRING
If you modify any of your wiring when making repairs or adding accessories, please use proper wire colors and notate your changes for the next owner. If possible, try to create all modifications in a way that’s reversible for the next owner. Use automotive grade wiring like GXL or TXL rated wire. They’re designed to withstand high temperatures and fuel/oil exposure.
WIRING DIAGRAMS:
MG TA & TB: https://ttypes.org/mg-ta-tb-wiring-diagrams-in-colour/
MG TC: https://ttypes.org/mg-tc-wiring-diagram-in-colour/
MG TD & TF: https://ttypes.org/mg-td-tf-wiring-diagram/
MGA: https://mgaguru.com/mgtech/electric/circ_wiring.htm
MGB & MGC: http://www.advanceautowire.com/mgb.pdf
Upgrading your electrical system can help reduce strain on your electrical system, eliminate maintenance items, and improve drivability. We’ll be reviewing some of our favorite upgrades as well as pointers for general electrical repairs and maintenance.
ALTERNATORS
In early MG’s, original generators produce approximately 22 amps while most “alternator-in-generator” upgrades will provide around 45. Our friends at BP Northwest provide alternators in generator housings for TD’s, TF’s and MGA’s that match the original generator style and even come with tach drives if needed. They look completely stock and are essentially a “bolt on” upgrade with only a minor wiring change to bypass the voltage regulator, which means you’ll never have to worry about whether your alternator is under-charging (or overcharging!).
MG TC (C45 style):
http://gener-nator.com/
MG TD/TF (C39/C40 style):
Negative ground: https://www.bpnorthwest.com/mg/mg-tc-td-tf/engine-electrical/alternator-generator-c39-c40-style-with-tach-drive-negative-ground.html
Positive ground: https://www.bpnorthwest.com/mg/mg-tc-td-tf/engine-electrical/alternator-generator-c39-c40-style-with-tach-drive-positive-ground.html
MGA:
https://www.bpnorthwest.com/mg/mga/engine-electrical/alternator-generator-conversion-mga.html
MGB:
Standard Lucas alternators for MGB’s only output between 34 and 45 amps but we find MGB’s typically get loaded with a lot more accessories too. It’s common to find owners adding phone chargers, cd players/radios, amplifiers, cooling fans, navigation units, air conditioning, etc. Our favorite upgrade is a Delco/Saturn alternator.
Alternator: Bosch AL8596N
Pigtail connector: Dorman 85854
Pulley: Powermaster 118
Delco/Saturn alternators do require some modification to fit. The instructions to add this alternator to your MGB can be found from the MG Club of Toronto.
https://mgtoronto.com/wp-content/uploads/2021/04/Alternative_Alternators.pdf
POSITIVE TO NEGATIVE GROUND
This is a quick note but we really encourage a lot of our customers to convert to negative ground. We find that a lot of people are perplexed by positive ground wiring and that’s completely understandable. At this point, practically every car is wired using negative ground. It’s a very discreet modification and makes your car easier to upgrade with accessories.
DISTRIBUTOR, COIL, ETC
Switching your ignition from a points distributor to electronic ignition eliminates another maintenance item. Worn distributors benefit greatly from electronic ignition because the modules are not sensitive to wear in the cam or the cam lobes.
Entire distributors can be purchased with electronic ignition modules too. They’re available from Pertronix, Accuspark, 123Ingition, and more.
It’s important to make sure that your coil has the proper resistance for the electronic ignition system. Too little resistance will burn up the module internally so make sure to reference the installation instructions to verify you have the proper ohm rating.
LED LIGHTING
LED lighting has become A LOT more popular in the last few years. LED’s draw a fraction of the current of an incandescent bulb and they provide much greater light output. If your car has been converted to negative ground, adding LED’s is a breeze.
We typically like to use universal 7” headlamps (Valeo Cibie’s or Hella’s) and fit H4 LED’s in the housing. The light pattern is still crisp with very good projection and the cars end up looking stock otherwise. We recommend using a passively cooled headlamp LED with a heatsink or straps that provides high light output but doesn’t require a fan to cool itself. They’re easier to fit inside the headlamp buckets of our MG’s and you don’t have to worry about fan failures or overheating bulbs.
It’s worth noting that LED lighting is that white LED’s come in different shades that vary between warm and cool color temperatures. Warm lighting looks similar to the original incandescent lighting while cool lighting looks like a modern blueish white. The color temperatures are rated on a kelvin scale. 3000k is a warm white while 6000k is little blueish.
You can see the differences in lighting here: https://www.ledlightingwholesaleinc.com/v/vspfiles/images/Kalvin%20Color.jpg
If you convert your brake lights to LED’s make sure that the visible difference between the running light and the brake light is noticeable for drivers behind you. I’ve seen cheap amazon bulbs that hardly have a difference in light output between the two. If people can’t tell when you’re braking, you’ve effectively made the care MORE dangerous.
We’re big fans of MAXGTRS’ 1157 bulbs for brake lights. They use high output Cree LED’s and are drop in replacements for incandescent bulbs. They can be found on Amazon: https://www.amazon.com/MAXGTRS-BAY15D-Signal-Condenser-Reverse/dp/B07KZMSN6Q/ref=cm_cr_arp_d_product_top?ie=UTF8
Tips for exterior lights:
Use bulbs that match the lens color. If you have a brake lens or side marker light that’s red, use a red LED. If you have amber turn signal lenses, use amber LED’s. The reason this is important is because white LED’s will make the lens color look washed out and pale.
RELAYS
If you’re not inclined to use LED’s in your headlights, installing relays are a fantastic way to improve incandescent lighting. With original wiring, power is run through the headlight switches. We’ve seen a lot of voltage drop at the headlights as well as burned up switches. When you install relays, the switch will trigger the relay but the power will be pulled directly from the alternator or battery.
Moss sells a great relay kit that matches the lucas wiring colors here: https://mossmotors.com/headlight-relay-kit
COOLING FANS
This portion is almost entirely for the late model MGB owners with the push fans. When the cooling systems are in perfect working order, the push fans don’t struggle with cooling the radiator. However, some of the fan motors we’ve seen need rebuilding/replacing. They draw a ton of current and don’t spin as well as they should, leading to high coolant temps and overheating.
Replacing the push fans with a puller fan is an easy upgrade if your original fans seem to not be cutting it. Moss Motors sells fan kits from Revotec and Hayden. Amazon has plenty of universal fan options available too. These puller fans can easily be added in place if the push fans for more effective cooling. Keep in mind that the fans will only draw air through the surface area that the fan covers so getting the largest size your radiator can take is important.
REPAIRS:
BATTERY CONNECTIONS & GROUND STRAPS
Clean, tight battery connections are a must. We also highly recommend making sure your battery cables are proper colors (no red ground cables!) as well as installing colored felt washers. They prevent corrosion and clearly indicate the terminals. Make sure your battery grounds and engine grounds are secured to clean metal. Use a thin layer of dielectric grease to prevent corrosion.
CONNECTORS
Make sure if your harness has spade connectors, ring/fork terminals, or butt splice crimps that the crimps are tight and the connections are secure. It’s not uncommon to find connectors that are crimped to the wire insulation instead of the wire. Also, make sure the connector is the proper size for the gauge of wire. Generally, red connectors will fit 22 to 18 gauge wire, blue will fit 16 to 14 gauge wire, and yellow will fit 12 to 10 gauge wire. If you tug on the wire and the connector slips off, you may have the wrong size connector or the crimp was bad.
Do not use wire nuts. Do not use solid core wire. Do not twist and tape wires together. Make sure solder joints are secure. Use heatshrink or electrical tape to insulate any exposed wiring or connectors.
MODIFIED WIRING
If you modify any of your wiring when making repairs or adding accessories, please use proper wire colors and notate your changes for the next owner. If possible, try to create all modifications in a way that’s reversible for the next owner. Use automotive grade wiring like GXL or TXL rated wire. They’re designed to withstand high temperatures and fuel/oil exposure.
WIRING DIAGRAMS:
MG TA & TB: https://ttypes.org/mg-ta-tb-wiring-diagrams-in-colour/
MG TC: https://ttypes.org/mg-tc-wiring-diagram-in-colour/
MG TD & TF: https://ttypes.org/mg-td-tf-wiring-diagram/
MGA: https://mgaguru.com/mgtech/electric/circ_wiring.htm
MGB & MGC: http://www.advanceautowire.com/mgb.pdf