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I have a '78 Spitfire that we tore down and built back up over the past several months. The car is all together now and runs, but the engine will start shutting down after anywhere from 5 to 40 miles of driving. When it has died but is still moving, the accelerator pedal has no effect. If I push and release the clutch, say in 3rd gear, the RPM obviously drops to zero, but then comes right back and I have about 2-3 seconds of power. It has the original Lucas 45DE distributor upgraded with the Pertronix Ignitor ignition system, as well as proper coil, new wires, cap, rotor, and plugs. Timing is at 10 degrees before TDC. Carb is the original ZS 150CD that has been professionally rebuilt. Fuel system is clean and flowing a regulated steady 2-3 PSI. Voltage to coil remains steady. My personal thought is the Pertronix unit is heating up and cutting out (as electronics do not like heat), but I wanted to see what this community thought about my problem. Any help is appreciated!
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Spitfire '78 cuts out after many miles of driving
- Thread starter KeyMan90
- Start date
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I had a Crane electronic ignition that cut out in hot weather. I sent it back to the factory and they said it was fine. I re-installed it and it continued to cut out. That was about 10 years ago. I've been running points ever since with no problems. I know zip about Pertronix. Others here can give you answers about that.
Rhodyspit75
Jedi Knight
Offline
Try opening the gas cap when it happens. If the vapor recovery system is blocked the tank can't get any air to replace the gas that has been drawn off. It's pretty common on spitfires.
Elva164
Jedi Trainee
Offline
Is it a sharp cut or a more gradual dying? If it's sharp, I would lean towards something electrical (the Petronix in particular). If it's more gradual, it's probably fuel related (like the situation Rhody suggested). I'd try swapping points and a condenser in and seeing what happens.
dklawson
Yoda
Offline
As others suggested above, a slow drop in power and speed would probably be fuel related (including trapped tank vacuum as Rhodyspit suggested). If it is a sudden or rapid onset, ignition is more likely.
You said you have the "proper coil". What do you mean by that and how is it wired?
According to the wiring diagram linked below, the '78 Spitfire has a ballast ignition wiring system.
https://www.triumphspitfire.com/images/wiring/78diagram.jpg
If you have retained the original ballast coil wiring and connected the Pertronix "red" wire to coil (+) the module will not be running on full voltage. Pertronix modules do not like running on reduced voltage. The common workaround is to connect the module's red wire to a switched 12V supply.
You said you have the "proper coil". What do you mean by that and how is it wired?
According to the wiring diagram linked below, the '78 Spitfire has a ballast ignition wiring system.
https://www.triumphspitfire.com/images/wiring/78diagram.jpg
If you have retained the original ballast coil wiring and connected the Pertronix "red" wire to coil (+) the module will not be running on full voltage. Pertronix modules do not like running on reduced voltage. The common workaround is to connect the module's red wire to a switched 12V supply.
Finally figured it out! Switched to points distributor, no difference. Still acted like ignition. After much frustration, we tore the carb apart and found two pieces of debris right atop the float needle. Cleaned that out and ran like a champ!
I had originally wired the car with straight 12v to the Pertronix system, which as we know now, was apparently working fine. After all this, tonight I switched to the points system with ballast resistor, 6v coil, and the 4th 12v boost wire from the solenoid for starting. The points are working great so I'm going to leave them in. I'd like to thank everybody for their input on this issue! Many thanks!!
I had originally wired the car with straight 12v to the Pertronix system, which as we know now, was apparently working fine. After all this, tonight I switched to the points system with ballast resistor, 6v coil, and the 4th 12v boost wire from the solenoid for starting. The points are working great so I'm going to leave them in. I'd like to thank everybody for their input on this issue! Many thanks!!
