Heat Cycling Causes Loose Faston spade terminals

[Prefect]

My engine recently stopped when the Lucas Spade teminal connecting the dizzy to the negative side of the coil just fell off. It had lost its spring grip due to many years of heat cycling.

As the loose lead was not visible (it had dropped down the side of the engine) this fault must be one of the most difficult to diagnose!

Test lamps and voltmeters don't work too well when its the earth that gets disconnected everything tested healthy.

I am posting this message to strongly suggest that Dizzy to Coil connections should be ring terminals a bit less convenient than spades but mostly imune to failures due to heat cycling.

[RobH]

The  usual failure with that lead is a break of the wire inside the insulation, close to the terminal.  That is because it is about the worst on the engine for waggling about, being virtually unsupported .   Ring terminals would not help with that. 

[Prefect]

Thank you Rob for your response, I appreciate the importance of considering all risks, my proposed solution was tabled to address an issue I experienced recently and wished to share.

[stuart]

14 hours ago, Prefect said:

Thank you Rob for your response, I appreciate the importance of considering all risks, my proposed solution was tabled to address an issue I experienced recently and wished to share.

FWIW up till late 3a and possibly very early 4  coil to dizzy lead was on ring terminals anyway.

Stuart.

[RogerH]

Regarding the coil, I would have thought that the wires leading to the contacts would be strapped to the coil body to stop them vibrating etc.

 

Roger

[Hamish]

I’ve had the low tension spade on my hi torque started lose its grip a couple times causing starting issues. 
I need to find a grippier version. 

[Don H.]

I’ve never had this problem on any 025 Faston-style quick-disconnect. 
 

I’d have thought a missing LT or ground wire from the coil on a wet-liner TR engine would be pretty easy to spot. They’re right there.