Are we damaging our engine by just ticking over?

[Kassia]

Hello

We have a Nanny Diesel engine in our boat which powers our batteries but also heats our water. As we are yet to buy a generator we generally run the engine a couple of hours each night and then longer at the weekends to maintain the batteries. Normally we just have the engine ticking over but I wonder if this damages it long term? Is it best to vary what we do to ensure we are not causing any problems?

Thanks

Kassia

[Dharl]

BUMP

 

this is an interesting question and would like to hear the answer. I find, in particular on the K&A, that you also do a lot of passage making at Tick Over only due to the lines of moored boats!

[Guest]

BUMP

 

this is an interesting question and would like to hear the answer. I find, in particular on the K&A, that you also do a lot of passage making at Tick Over only due to the lines of moored boats!

 

It may be on tick over BUT it will be under at least a degree of load.

 

It is as I understand it running the engine on tick over without any load in it that is supposed to cause the issue (bore glazing). Hence you sometimes see moored boats running with the prop turning in gear. (Contrary to CRT regs)

 

There is differing views as to whether it is a genuine problem or not. Some say it is but I've also read on here it's not a significant issue, and it depends on engine type.

Edited October 15, 2013 by The Dog House

[nicknorman]

I think its likely to be an issue on a brand new engine, but not one that has been run in. Also, there is a difference between running at idle for a few hours a day for a week or two and then using the engine properly, versus never doing anything else. If you only ever want to run your engine tied up, why not move into a house?

[Old Son]

Beta say no problem provided you use the correct grade oil.

[nicknorman]

One advantage of modern Betas is that the large alternators present as much or more load on the engine as being in gear. But I always run ours above tickover for charging so that the alternator is well cooled - typically 1100 as opposed to idle of 850.

[Kae]

Beta 1505 (37.5) running at 1100rpm appears to give maximum amps from both alternators, no issues running to charge batteries and I manually pair the alternators as the domestic bank will max out just the domestic alternator.

[Guest]

I think its likely to be an issue on a brand new engine, but not one that has been run in. Also, there is a difference between running at idle for a few hours a day for a week or two and then using the engine properly, versus never doing anything else. If you only ever want to run your engine tied up, why not move into a house?

 

Interesting article here would seem to confirm that it is indeed more of an issue on newer not yet run in engines.

 

http://coxengineering.sharepoint.com/Pages/Boreglazing.aspx

[dor]

Vetus say their gearboxes (Technodrive) should not be left in neutral when the engine is running for more than 20 minutes, due to the way the input shaft is lubricated. PRM150s do not have the same problem.

 

As for charging, initially I get maximum amps when the engine is run at about 1100 - 1200 rpm. However once the current drops to below about 25 amps as the batteries charge up, I get virtually the same charge at 850rpm tickover.

[Phil Ambrose]

What is wrong with glazed bore? When engines are produced the engineers go to great trouble to hone the bores to an almost mirror finish

 

Phil

[Guest]

What is wrong with glazed bore? When engines are produced the engineers go to great trouble to hone the bores to an almost mirror finish

 

Phil

 

Oh no they don't!

 

From the article I linked to.

 

 

I seem to remember when rebuilding engines on my old Mini's (not diesels) we used to de-glaze the bores before installing the pistons. You could get a special tool to get the correct pattern as shown but as we were poor student nurses we just used wet n dry which was probably completely ineffective.

Edited October 15, 2013 by The Dog House

[Kae]

What is wrong with glazed bore? When engines are produced the engineers go to great trouble to hone the bores to an almost mirror finish

 

Phil

 

Not quite, they can look shiny but the cross-hatching is crucial for piston ring lubrication. If they weren't there, the rings would wear very quickly.

[Timleech]

 

 

 

I seem to remember when rebuilding engines on my old Mini's (not diesels) we used to de-glaze the bores before installing the pistons. You could get a special tool to get the correct pattern as shown but as we were poor student nurses we just used wet n dry which was probably completely ineffective.

 

No, Wet or dry or similar abrasive can work quite well, even if it doesn't produce the ideal pattern.

 

Tim

[Phil Ambrose]

So why don't cylinder bores glaze when run under load?

Phil

[Guest]

So why don't cylinder bores glaze when run under load?

Phil

Have a read of the article I linked to.

[by'eck]

What is wrong with glazed bore? When engines are produced the engineers go to great trouble to hone the bores to an almost mirror finish

 

Phil

 

 

Sorry Phil its the correctly performed running in process that provides the mirror looking finish. The new bores are deliberately cross hatch honed to provide a surface like hills and valleys when magnified. A good running in regime then knocks off the tops off the hills leaving rings and bores matched but retaining the valleys for oil retention. inadequate cylinder pressures doesn't force the piston rings into good contact with the bores, leave the tops of the hills just rounded and work hardened. This extra hard but uneven surface with honing marks still showing, results in blow past causing low compression and high oil consumption.

 

FWIW new/refurbished low revving aircraft piston engines are run flat out until the oil consumption stabilises indicating the running in process is complete.

 

A similar effect can happen with a run-in engine where the same inadequate cylinder pressures caused by excessive idling with no load, leave the bore surface work hardened, much like what happens when trying to drill metal with a blunt drill bit. Glazing occurs when the ensuing blow past causes oil on the bores to burn leaving a hard enamel finish which fills the valleys and so reduces bore lubrication.

Edited October 15, 2013 by by'eck

[Phil Ambrose]

Thanks for that By,eck that makes sense to me, I used to produce test engine blocks for Ford when they started to produce V 6 and V 4 engines and though this was a lot of years ago I can remember boring out the bores ready for honing and the Hone that was used was in the form of a cylinder sized mandrill for want of a better word which carried a series of hardened rollers which were designed to do exactly the function you described ie flattening the peaks and leaving the troughs. Another thing that I recall was making a cylinder head from scratch, just a lump of metal, we had 90 hours to make one, 180 hours for a pair for a V 6 of course today it's a lot different with CNC machines but in my day we didn't even have calculators so all our maths had to be done long hand, multiplying 6 digits by 6 digits to work out all the Trig we needed. Boy how the world has changed.

 

Phil

[by'eck]

Thanks for that By,eck that makes sense to me, I used to produce test engine blocks for Ford when they started to produce V 6 and V 4 engines and though this was a lot of years ago I can remember boring out the bores ready for honing and the Hone that was used was in the form of a cylinder sized mandrill for want of a better word which carried a series of hardened rollers which were designed to do exactly the function you described ie flattening the peaks and leaving the troughs. Another thing that I recall was making a cylinder head from scratch, just a lump of metal, we had 90 hours to make one, 180 hours for a pair for a V 6 of course today it's a lot different with CNC machines but in my day we didn't even have calculators so all our maths had to be done long hand, multiplying 6 digits by 6 digits to work out all the Trig we needed. Boy how the world has changed.

 

Phil

 

I believe modern machining techniques remove to a large degree the need for running in by removing the tops of the hills leaving only the valleys for oil retention. Doesn't remove the likelihood of bore glazing through inadequate cylinder pressures though.

[goodboy]

The cross-hatching is crucial for piston ring lubrication and bedding in of the rings on a new engine

and the running in is now done at the factory on a test bed

[by'eck]

The cross-hatching is crucial for piston ring lubrication and bedding in of the rings on a new engine

and the running in is now done at the factory on a test bed

 

I remember visiting the Moto Guzzi motorcycle factory in Italy where their famous V twin engines were built. They had a rig that took around twenty part completed engines at a time. Each had external oil pressure feed and the engines turned at high rpm for several hours by electric drive to provide initial running in of the cast iron and later nikasil (nickel plating onto alluminium) bores.

[alan_fincher]

BUMP

 

this is an interesting question and would like to hear the answer. I find, in particular on the K&A, that you also do a lot of passage making at Tick Over only due to the lines of moored boats!

 

The fact this is posted in the Fishing, Walking & Cycling forum may be part of the explanation it found no takers first time around!

 

("Tick over" going along clearly places more loading on the engine than "tick over" out of gear when moored up, of course, so I doubt the K&A issue is damaging an engine!)

[Neil2]

 

The fact this is posted in the Fishing, Walking & Cycling forum may be part of the explanation it found no takers first time around!

 

("Tick over" going along clearly places more loading on the engine than "tick over" out of gear when moored up, of course, so I doubt the K&A issue is damaging an engine!)

 

Yes - it's a pity, I've certainly learned something from this discussion and no doubt others would find it interesting too - can the mods move it to the relevant section?

[Ange]

 

Yes - it's a pity, I've certainly learned something from this discussion and no doubt others would find it interesting too - can the mods move it to the relevant section?

It'd be worth reporting your own post and requesting they move it - otherwise they might miss this request.

[onionbargee]

cut and paste, not my words..........

"this is VERY HARMFUL to any engine. Check you car owner's manual. It will note that if the car is driven regularly on short trips, or idles for extended periods, the oil change interval must be shortened. This is because the engine is not allowed to reach operating temperature, where harmful combustion by-products are eliminated. This acidic by-product accumulates in the oil, where it chemically attacks the engine bearings.

Here's what happens when a diesel engine is idled:

Timing gear backlash [gear rattle] is maximized, leading to increased wear

The cylinders get glazed, leading to low compression

The engine is run at below operating temp, leading to carbon accumulation in the combustion chamber, injector tips, piston rings, piston crown, valves heads, seats, and stems, exhaust manifold, turbocharger, etc. Carbon on these parts will lead to accelerated wear, and possible piston ring sticking and low engine compression.

Also, the injected fuel gets past the piston rings, because the engine is not at the correct temperature, and dilutes the lube oil. This compromised oil is sent to ALL the engine bearings, where it increases bearing wear.

There's more, but isn't this enough to convince one that engine idling should be avoided."

[churchward]

 

Interesting article here would seem to confirm that it is indeed more of an issue on newer not yet run in engines.

 

http://coxengineering.sharepoint.com/Pages/Boreglazing.aspx

This has always been the case. There is more chance (although examples of true bore glazing are very rare) of glazing on a new engine before the bore, compression and more importantly the oil control rings have had a chance to bed in together. Eventually of course there will be wear and tear on an with many hours of running where you won't get bore glazing but bore polishing where the rings and bore are starting to wear out and get put of shape.

 

Personally I would invest in a nice quiet generator for charging batteries. A small diesel boiler would be good to if you need to create hot water in a calorifier. It will be cheaper to run than the engine and less expensive to replace when worn out.

 

cut and paste, not my words..........

"this is VERY HARMFUL to any engine. Check you car owner's manual. It will note that if the car is driven regularly on short trips, or idles for extended periods, the oil change interval must be shortened. This is because the engine is not allowed to reach operating temperature, where harmful combustion by-products are eliminated. This acidic by-product accumulates in the oil, where it chemically attacks the engine bearings.

Here's what happens when a diesel engine is idled:

Timing gear backlash [gear rattle] is maximized, leading to increased wear

The cylinders get glazed, leading to low compression

The engine is run at below operating temp, leading to carbon accumulation in the combustion chamber, injector tips, piston rings, piston crown, valves heads, seats, and stems, exhaust manifold, turbocharger, etc. Carbon on these parts will lead to accelerated wear, and possible piston ring sticking and low engine compression.

Also, the injected fuel gets past the piston rings, because the engine is not at the correct temperature, and dilutes the lube oil. This compromised oil is sent to ALL the engine bearings, where it increases bearing wear.

There's more, but isn't this enough to convince one that engine idling should be avoided."

 

This is a dreadful over simplification and although contains some truth it is missing the point for an idling engine over an extended period of time.

 

The short trip engine in a car may well not reach operating temperature but this is because it has not had enough time to do so. An idling engine WILL reach operating temperature given enough time. Running an engine in a narrowboat for a couple of hours is more than enough time to get as warm as it should do.

 

What about those engine that boil when stuck in traffic stationary on a motorway?

Edited October 22, 2013 by churchward