glow plugs and slight overvoltage?

[canadacountry]

thanks for not minding me asking about 'little' things there and there, anyhow heres my next one..

how bad is it to drive a glow voltage 1v-2v higher than its paper rating considering that its generally only on for a short time as well?
(I partially asked this because of how for example with just NGK alone there are a lot of models that are only 1v apart from each others, etc)

 

[Barrman]

What engine are you working on? The Chevy CUCV 6.2 engines use 12 volt glow plugs. However, fully charged batteries should deliver 12.6 volts at first but will probably be down to 10.9 or so volts after all 8 pull voltage for 12-18 seconds. But, if slave starting from a running vehicle the voltage could be up to 14.4 or so.

That make sense? I don’t see any issues with a few volts up or down. Just don’t double the rated voltage. A 12 volt glow plug getting hit with 24 volts will explode in normally around 8 seconds is my experience.

 

[canadacountry]

ah I didn't have an engine in mind, just that it was a truck diesel (like for example the M35's Continental engine)

and regarding literally going crazy on the voltage, you should see the stories about european people that somehow thought that flipping their psu's little red switch from 220v to 110v would "make it go faster" but nope that simply cause a big puff of black smoke only one second later!

 

[Barrman]

The M35A2 multifuel engine doesn’t have glow plugs.