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

[James H]

Is running your engine in idle out of gear bad for the engine??? We have a fairly modern ISUZU 4 cylinder engine with a decent alternator and we run an inverter etc aswel! 

I've heard on this forum that with a modern engine and alternator etc it doesn't make a difference so much, I am keen to know if this is true, and if so why this is the case!

 

Thanks in advance,

 

James. 

[frahkn]

10 minutes ago, James H said:

Is running your engine in idle out of gear bad for the engine??? We have a fairly modern ISUZU 4 cylinder engine with a decent alternator and we run an inverter etc aswel! 

I've heard on this forum that with a modern engine and alternator etc it doesn't make a difference so much, I am keen to know if this is true, and if so why this is the case!

 

Thanks in advance,

 

James. 

I've done this since I've owned this boat - 7 years. Even on days when we cruise we don't switch the engine off until we have showered.

 

It's a Beta 43 and doesn't seem to have been harmed by this treatment. I run it a bit quicker than tick-over.

[Tony Brooks]

It is all to do with load and as most modern engine alternators will put a greater load on the engine than canal cruising early in the charging cycle it won't do any harm, especially if you keep the revs at the speed than gives maximum alternator output. Later in the charging period it may be more debatable and on modern engines I would not like to comment. I suspect better spec oils have done much to minimise any problems in this respect but if the engine uses a stepped top ring (not a bore rifge dodger) that is designed to twist under compression I would be far more wary about doing it. Not seen such a ring in any engines but know they exist or did exist.

[James H]

4 minutes ago, Tony Brooks said:

It is all to do with load and as most modern engine alternators will put a greater load on the engine than canal cruising early in the charging cycle it won't do any harm, especially if you keep the revs at the speed than gives maximum alternator output. Later in the charging period it may be more debatable and on modern engines I would not like to comment. I suspect better spec oils have done much to minimise any problems in this respect but if the engine uses a stepped top ring (not a bore rifge dodger) that is designed to twist under compression I would be far more wary about doing it. Not seen such a ring in any engines but know they exist or did exist.

Thanks very much I'll look into this... So how would I go about finding out what the most efficient RPM is to run my engine at whilst charging my batteries? Thanks again, much appreciated...

[Alan de Enfield]

6 minutes ago, James H said:

Thanks very much I'll look into this... So how would I go about finding out what the most efficient RPM is to run my engine at whilst charging my batteries? Thanks again, much appreciated...

Start at tickover, look to see how many amps are going into the batteries, increase revs and the amps will increase, keep increasing the revs until the amps stop increasing, that's the 'best' speed.

 

As the battery becomes charged the amps will drop, reduce your revs , then increse then again until you reach maximum amps,

Repeat

Repeat

[IanD]

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.

Edited November 3, 2020 by IanD

[noone]

I have been told many times over the years that it is not good for engines to be run on idle with no load as it glazes the bores:Bore glazing occurs at low speed and light load operations, particularly resulting from blow-by in new engines. Exhaust gases passing piston rings in newly built or re-built bores can react with oil and wear products, forming a golden-coloured varnish glaze.

I have a modern Barrus Shire,and (I cant remember the exact wording) but is something like:run the engine at 3/4 revs,under load for at least 15 mins each week.This burns off any glazing and coke in the exhaust.

I have also heard from many an owd boater,that if your engine is smokey,get onto a river and "open er up" to burn  the glaze off and de coke!!.

Many n.b. engines are not run with enough load for long enough due to the nature of canal cruising.

[Athy]

Five minutes of reading the Brexit thread causes bore glazing.

[dor]

Just cruising at normal canal speed would probably be considered running with no load by most engine manufacturers.  It used to be considered a problem, but doesn't seem to bother people these days.

Note that it is against the rules to run your engine in gear while moored up as it damages the bank and can cause piling to collapse.

[James H]

The difference is the engine is in gear which I believe puts it under load...

[dor]

4 minutes ago, James H said:

The difference is the engine is in gear which I believe puts it under load...

True, but not very much.  As Tony says, a decent alternator charge will put more load on the engine than cruising.

[Man 'o Kent]

Maybe someone would care to enlighten me about the difference between a "glazed" and a "normal" bore?

 

 

[frahkn]

4 hours ago, 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.

I have only have my Beta 43 at 1200rpm on rivers, cruising on canals it is usually at 900 to 1000.

 

I was once told it was over propped but as it hasn't caused me any problems so far (touch wood) I've left things be.

[Alan de Enfield]

59 minutes ago, Man 'o Kent said:

Maybe someone would care to enlighten me about the difference between a "glazed" and a "normal" bore?

 

 

One has a window in it and the other one doesn't.

[Man 'o Kent]

3 minutes ago, Alan de Enfield said:

One has a window in it and the other one doesn't.

Very droll

 

I have done some very cruel  things to entirely innocent engines in the past including inserting windows. Photographing injector plumes in 2/1,000,000's of a second was one.

[IanD]

1 hour ago, frahkn said:

I have only have my Beta 43 at 1200rpm on rivers, cruising on canals it is usually at 900 to 1000.

 

I was once told it was over propped but as it hasn't caused me any problems so far (touch wood) I've left things be.

What size prop have you got? IIRC 18" x 12" is recommended for a Beta 43 with a 2:1 PRM150, and I've usually found cruising rpm (on normal narrow canals) to be ~1200rpm on boats fitted with these.

 

When I spoke to Beta recently about battery charging with big alternators (2 x 24V 100A) they repeated the advice about 1200rpm or above, though admittedly this is almost certainly a much heavier alternator load (almost 10bhp!) than you have.

Edited November 3, 2020 by IanD

[Tony Brooks]

1 hour ago, Man 'o Kent said:

Maybe someone would care to enlighten me about the difference between a "glazed" and a "normal" bore?

 

 

A "normal" bore would have been honed as the final machining process using fine spinning grinding stones pushed up and down the bore. This results in the bore being "scratched with many fine lines in a diamond formation. the bore is silver and looks shiny but is not, you don't get much of a reflection in it. These scratches hold aa tiny amount of oil an dhelp the rings grip the bore.

 

When a bore glazes these fine lines get filled with products of incompletely combusted oil and/or fuel. This tends to be caused by low combustion temperature running. (that is NOT low coolant temperature). The rings now tend to slip across the surface and don't grip so the scraper rings do not remove the excess oil that then burns. Glazed bores tend to look a bit dirty but with  a pronounced shine.

[BWM]

I was under the impression that that glazing is more of an issue with mineral oils, not modern multigrade types used in later engines. 

[IanD]

26 minutes ago, BWM said:

I was under the impression that that glazing is more of an issue with mineral oils, not modern multigrade types used in later engines. 

http://coxeng.co.uk/engine/bore-glazing-and-polishing-in-diesel-engines/

[frahkn]

1 hour ago, IanD said:

What size prop have you got? IIRC 18" x 12" is recommended for a Beta 43 with a 2:1 PRM150, and I've usually found cruising rpm (on normal narrow canals) to be ~1200rpm on boats fitted with these.

 

When I spoke to Beta recently about battery charging with big alternators (2 x 24V 100A) they repeated the advice about 1200rpm or above, though admittedly this is almost certainly a much heavier alternator load (almost 10bhp!) than you have.

I'm not currently on the boat so can't look up the pitch but the diameter is 22". The boat is deep drafted - 31" under the skeg.

 

 

[IanD]

15 minutes ago, frahkn said:

I'm not currently on the boat so can't look up the pitch but the diameter is 22". The boat is deep drafted - 31" under the skeg.

 

 

Unless the prop pitch is very small (do you know what it is?) then you are definitely overpropped -- assuming a 2:1 gearbox I doubt you'll even reach 2000rpm at WOT.

 

Does explain why you cruise at 900-1000rpm though, and must make going "dead slow" past moored boats difficult since the Beta 43 idles at 850rpm... ?

[Flyboy]

1 hour ago, BWM said:

I was under the impression that that glazing is more of an issue with mineral oils, not modern multigrade types used in later engines. 

I think you will find it's the other way round.  Modern oils have a lot of additives that are needed to protect high revving car engines that are running at circa 100 C.  Canal boat engines rarely get to much over 70C so the additives don't do very much and cause the the bore glazing. At low temperatures the additives stay gummy and bung up the honed bore surfaces which reduces the lubrication and subsequently polishes up the bores into a hard glaze.

[BWM]

14 hours ago, IanD said:

http://coxeng.co.uk/engine/bore-glazing-and-polishing-in-diesel-engines/

Thanks, a well written and informative article. 

 I was advised by Peter Thompson to ensure that my Jp3 was run under load after a rebuild, and followed that advice, after reading this i'm glad i did!

  I guess the op has less to lose now that the engine has long passed the running in period.

[Tracy D'arth]

15 hours ago, Flyboy said:

I think you will find it's the other way round.  Modern oils have a lot of additives that are needed to protect high revving car engines that are running at circa 100 C.  Canal boat engines rarely get to much over 70C so the additives don't do very much and cause the the bore glazing. At low temperatures the additives stay gummy and bung up the honed bore surfaces which reduces the lubrication and subsequently polishes up the bores into a hard glaze.

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.

[Alan de Enfield]

11 minutes ago, Tracy D'arth said:

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.

 

They'd be the ones with the 'glazed bores'