Idling & glazing?

[jamie N]

I'm a raggie, but thought the brethren here would be more aware of the nuances between idling a single cylinder diesel to charge the batteries, and charging the batteries using (say) 60% maxRPM.
Would glazing be more likely in one than the other?
As an aside, how does a motor 'know' when it's under load at high RPM and full heat, or where it's just idling at full heat?
Many thanks from a yottie....

 

[lynallbel]

Only ever seen one motor shagged out with glazed bores due to excessive idling, and that was a council gritter that was left idling for weeks at a time, Iirc it had 30k on the clock.

 

[LittleSister]

The estimable Vyv Cox (of this parish) has the information you seek on his rather wonderful website, here -
Bore glazing and polishing in diesel engines

 

[Tranona]

I'm a raggie, but thought the brethren here would be more aware of the nuances between idling a single cylinder diesel to charge the batteries, and charging the batteries using (say) 60% maxRPM.
Would glazing be more likely in one than the other?
As an aside, how does a motor 'know' when it's under load at high RPM and full heat, or where it's just idling at full heat?
Many thanks from a yottie....

Charging batteries at 60% maximum revs puts no more load on the engine than at tickover - or more precisely when the alternator is generating the charge the battery will take. As Vyv's explanation will tell you the dangers of light load running are incomplete combustion and not getting to working temperature. That is what cause exhaust elbows to coke up and possible bore glazing.

Generally speaking these sort of issues do not arise with MOBOs because to move their engines need to be well loaded, and in fact particularly with big high powered diesels the problem is more keeping them in their operating window.