What happens if you use the wrong ignition coil? (1 Viewer)

[fanboy]

Out here in the boonies, people use whatever ignition coil physically fits their engine, and don't care about anything else. When I first got my LX470, it had ignition coils from probably a Camry -- it ran like crap, but it also had a dozen other faults that could be attributed to.

And now an acquaintance wants my old (still working) LX470 ignition coils to use in his Corolla. I warned him that it will mess up his engine, but he doesn't care.

I'm wondering: in what specs do ignition coils differ across different engines, and what happens if you install an ignition coil that fits physically but is designed for a different engine? Obviously, not planning to do this on my own vehicles, but just curious.

Thanks for any advice.

 

[gnob]

How will it mess up his engine?
Coils are coils. Do a part number cross reference between models. unlike domestics, Toyota uses many parts across several vehicles.

 

[fanboy]

If coils are coils, then why do we have different coils for every model engine?

 

[gnob]

Because engineers are assholes.

If coils are coils, then why do we have different coils for every model engine?

 

[gnob]

See my updated pic for your unique land cruiser coils
Oh wait lexus coils.

 

[aztoyman]

There are different coils for electronic ignitions VS old points ignitions. In that case its the resistance of the coil that matters. AND, some vehicles have a ballast resister in the wire to the coil and some require a resister IN the coil. I have NO idea about differences in modern engines. Maybe see if there is a spec for ohms or maybe a difference in connectors??

 

[paulsmiths]

A malfunctioning ignition coil will cause your vehicle to misfire when you accelerate. In extreme cases, a misfire could cause your vehicle to shut down while you are driving. The misfire is a result of one of the cylinders firing incorrectly or not at all.

 

[Grayscale]

Is this a thread about coil-theory?

I think that if I left my 75 2F with the coil (ignition) on and the engine not running, I would risk heating the coil excessively if doesn't go thru charge and discharge cycles with the points telling it to fire. That said, a coil should match the kind of spark that the plugs can perform. If a plug is too gapped, or more likely fouled, then the coil wouldn't discharge properly. Match your coil to the plug gap (voltage needed for spark), at very minimum. There is also a dwell angle, which is the amount of time (rotation, angle in degrees) of discharge, I don't know if dwell angles vary, but, it was an understood concept when distributors were present and worked using points.

I was reading somewhere that you can measure resistance in your coil, just to ensure that it hasn't burned out, internally.

I've been thinking that I would love to monitor my coil electronically, In theory, it would be easy to see how each cylinder performs based on the pattern of discharge from the coil. That would be a neat thing, because my 2F is just under Factory specs for vacuum. Instead of a rebuild, I just fixed the oil leak on the valve stems, and clean/replace the plugs every oil change. It performs great, tons of torque, good mpg, no visible smoke. However, small amounts of oil must be getting past the rings and depositing carbon on the plugs. It was a junk-yard engine that drank rain - the carb throttle/butterfly was seized and rottted completely. If an ignition monitoring system like this works, you could see how the engineers skipped low-hanging fruit, making complex emission systems that dealt with symptoms of pollution, rather than identifying its real cause and informing the driver with a 'check ignition, cylinder #5' rather than a 'check engine' light.