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Is running the engine out of gear bad practice???


James H

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27 minutes ago, Tracy D'arth said:

Good for not glazing bores is an oil with minimal additives and even better, if that is possible, a recycled oil with a bit of "ash" still in it.

 

My old mechanic friend swore that a handful of fine sand chucked into a running engine intake would sort out glazing. As he managed to keep a fleet of old delivery trucks running way past their normal life he obviously knew something. These trucks were on postal duty and were left idling all day once they had got them running in a morning.

He moved on to looking after the ailing DMUs in a rail yard at Stalybridge. These Gardner engines were so knackered that once they were started they were left ticking over for days and nights. Fuel costs didn't matter to BR. The vibrations use to cause the windows to fall out.

All the reputable sources I can find (including the one I linked to) say that chucking [xxx] into an engine might help clean out cr*p in the short-term but is worse than useless at curing bore glazing, in spite of all the people like your old mechanic friend who believe otherwise ?

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The load from Alternators at higher RPM is OK and should be enough to put enough load on the engine.

 

Roughly speaking each 25amp of Alternator charge (actual amps produced not maximum of the alternator) consumes about 1-2HP  or so from the engine depending on the efficiency of the alternator and there will be some constant mechanical drive force as well.

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1 hour ago, churchward said:

The load from Alternators at higher RPM is OK and should be enough to put enough load on the engine.

 

Roughly speaking each 25amp of Alternator charge (actual amps produced not maximum of the alternator) consumes about 1-2HP  or so from the engine depending on the efficiency of the alternator and there will be some constant mechanical drive force as well.

25 amps x 14V (charging) is 350W, typical 12V alternator efficiency is 50%-60%, even at 50% this is only 700W, even allowing some extra for belt losses this is still <1bhp.

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2 hours ago, IanD said:

25 amps x 14V (charging) is 350W, typical 12V alternator efficiency is 50%-60%, even at 50% this is only 700W, even allowing some extra for belt losses this is still <1bhp.

1hp or so is a reasonable estimate.  I agree it may be less than 1 but most will go by the 1hp as a rule of thumb.  

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On 03/11/2020 at 17:16, IanD said:

Running at idle rpm under a heavy load (e.g. alternator putting out lots of amps) is not recommended by many engine manufacturers, including Beta -- in the installation manual they say not to run for long periods when charging below 1200rpm. I suspect this could be due to things like torsional resonances or vibration at low rpm overstressing the flexible elements in the drive plate and causing early failure, but this is just an educated guess.

beta1200.PNG

The reason for this is the cyclic irregularity of an engine running at idle. By increasing the speed it will smooth the engine out. Beta have had a few problems in the past with crank pulleys coming loose. The cause, running at idle to charge batteries.

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11 hours ago, Steve56 said:

The reason for this is the cyclic irregularity of an engine running at idle. By increasing the speed it will smooth the engine out. Beta have had a few problems in the past with crank pulleys coming loose. The cause, running at idle to charge batteries.

Cyclic torque variation form firing impulses is the cause, but I thought Beta had cured the pulley problem by using the splined power takeoff on the crankshaft nose instead of just bolting more pulleys on?

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1 hour ago, IanD said:

Cyclic torque variation form firing impulses is the cause, but I thought Beta had cured the pulley problem by using the splined power takeoff on the crankshaft nose instead of just bolting more pulleys on?

 

Yes, all Beta 43 engines from 2006 onwards have the splined takeoff left on. (On plant equipment is is used to drive various devices). Previously they used to cut it off and secure the pulleys with a Woodruff key.

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2 hours ago, cuthound said:

 

Yes, all Beta 43 engines from 2006 onwards have the splined takeoff left on. (On plant equipment is is used to drive various devices). Previously they used to cut it off and secure the pulleys with a Woodruff key.

Ĺ

 

3 hours ago, IanD said:

Cyclic torque variation form firing impulses is the cause, but I thought Beta had cured the pulley problem by using the splined power takeoff on the crankshaft nose instead of just bolting more pulleys on?

Yes they have relatively recently used this pulley mod. Not sure if it is on all engines. It is still good practice to run at a higher speed for charging, just smooths everything out.

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2 hours ago, Steve56 said:

Ĺ

 

Yes they have relatively recently used this pulley mod. Not sure if it is on all engines. It is still good practice to run at a higher speed for charging, just smooths everything out.

The warning I posted is from the latest Beta engine manual (Beta 14 to Beta 115), AFAIK all these use the splined takeoff. I seem to remember reading somewhere else that with this idling under load can kill the drive plate due to torsional vibrations but I can't find it...

Edited by IanD
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