Running engine (diesel) with the ignition turned off

[38mess]

It won't harm it at all. A guy I used to go sailing with used to turn the ignition off with the engine still running ( Perkins) lock the wheelhouse door, go to the engine box, lift it up and pull the stop lever before going home. He had been doing this for 25 years apparently with no Ill effects.

 

[RichardS]

It won't harm it at all. A guy I used to go sailing with used to turn the ignition off with the engine still running ( Perkins) lock the wheelhouse door, go to the engine box, lift it up and pull the stop lever before going home. He had been doing this for 25 years apparently with no Ill effects.

See post #2 .... but whatever you do, do not read post #155 as that one is a pile of poo.

Richard

 

[JumbleDuck]

I think it's an energised-to-stop solenoid which runs via relay from a timer on the on/off switch (which at my request is a button, not a key).

I was wrong, although in my own defence I was working on dud information.

The ignition switch is simply an on-off switch, with three switched outputs. One of these goes to a Denso stop relay which also has a fused but unswitched supply, an earth and a connection to the stop solenoid which goes high for ~20 seconds after the wire from the ignition switch goes low. My error was in thinking that the timing system was in the switch, as I had been told.

How do I know this? Because the damn thing failed again yesterday, this time because one of the connectors in the pathetically inadequate fuse holder had failed in fatigue, but remained in position.

I have now replaced the Nanni fuse holder completely with the best Largs Chandlers could do. mounted in a convenient place rather than at the inaccessible back of the engine. It's a bit of a bodge for now (a certain amount of choc-blockery is involved) bit I'll tidy it up when I next visit the boat and have my "doing nice wiring" tools with me.

Many thanks to VicS and PaulRainbow for words of wisdom and encouragement. Now, back to the hole digger. Has he reached the mantle yet?

 

[convey]

I don't know, has our on forum mechanical genius admitted that the shape of a piston and combustion chamber determines the compression ratio of an engine yet?

 

[RichardS]

I don't know, has our on forum mechanical genius admitted that the shape of a piston and combustion chamber determines the compression ratio of an engine yet?

You said "I forget if anyone conceded that piston and combustion shape and deck height, actually determine compression ratio, rather than having nothing to do with it, as some argued."

You also said " "piston shapes don't make the compression, but their shapes and their match determines the compressed volume, that determines the compression ratio" .

Now, which statement do you wish to stand by? It's long past time to piss or get off the pot.

Richard

 

[convey]

You appear to lack reading comprehension skills, as well as technical understanding.

Try going back and copy and pasting the entire context for the second statement. If you don't understand what was being said, I am happy to take you through it, slowly and clearly, step by step.

 

[RichardS]

You appear to lack reading comprehension skills, as well as technical understanding.

Try going back and copy and pasting the entire context for the second statement. If you don't understand what was being said, I am happy to take you through it, slowly and clearly, step by step.

Errrrrr ..... your post #139 said "I suppose strictly speaking you could argue that the shapes "don't make the compression" or something, but their shapes and their match determines the compressed volume, that determines the compression ratio. "

For reasons of providing context, I abbreviated it to "piston shapes don't make the compression, but their shapes and their match determines the compressed volume, that determines the compression ratio"

I'm struggling here.

Richard

 

[NotBirdseye]

Sorry Richard on this one I think you've lost the point.

Edit as requested 2020-08-06:
Sorry Richard I think you've lost the point on the matter of whether Convey was contradicting himself or making a distinction that didn't match. That being said I do have to award the point on the underlying argument based on the accepted Engineering definitions that the shape of the piston has no bearing on the compression ratio. On this matter I think Convey is struggling to understand the disconnect between the two principles.

On the first part of the first quote he was asking a question not making a statement and it seems from my pov that compression is different from compression ratio. In the second quote, he wasn't making an assertion that psiton shapes don't make the compression, but rather accepting a hypothetical argument and going on to clarify their position about what does determine the compression ratio. There's nothing there that is contradictory. (Maybe someone else will clarify where the contradiction is).

 

[penberth3]

I don't know, has our on forum mechanical genius admitted that the shape of a piston and combustion chamber determines the compression ratio of an engine yet?

Here we go again.

Compression Ratio is the ratio of two volumes, the shapes are irrelevant.

 

[rogerthebodger]

Here we go again.

Compression Ratio is the ratio of two volumes, the shapes are irrelevant.

I and several others have posted how to calculate the CR I even gave a way without even taking the engine apart (except removing the injector or spark plug)

This is a pi**ing contest between two alpha males.

I think the mods should lock this thread as there is no more productive posts.

The OP's question was answered long ago and not its just pointless thread drift.

 

[coveman]

I and several others have posted how to calculate the CR I even gave a way without even taking the engine apart (except removing the injector or spark plug)

This is not a pi**ing contest between two alpha males.

I think the mods should lock this thread as there is no more productive posts.

The OP's question was answered long ago and not its just pointless thread drift.

Yes, more like a game of "ping pong"!

 

[NotBirdseye]

Sod it. Time for an authoritative source...

Compression ratio - Wikipedia

 

[RichardS]

Sorry Richard on this one I think you've lost the point.

On the first part of the first quote he was asking a question not making a statement and it seems from my pov that compression is different from compression ratio. In the second quote, he wasn't making an assertion that psiton shapes don't make the compression, but rather accepting a hypothetical argument and going on to clarify their position about what does determine the compression ratio. There's nothing there that is contradictory. (Maybe someone else will clarify where the contradiction is).

I've no idea whether you are talking about the two phrases in post #345 or the two phrases in post # 347.

Richard

 

[penberth3]

Sod it. Time for an authoritative source...

Compression ratio - Wikipedia

I wouldn't call Wikipedia authoritative! It does give the formula previously quoted by Robershaw.

 

[NotBirdseye]

Both. I'm going by the wikipedia article now though!

Convey isn't contradicting himself, just wrong. The shapes, size or dimensions of whatever have nothing to do with Compression ratio.

 

[jbweston]

This is not a pi**ing contest between two alpha males.

No they aren't alpha males. They're argumentative anoraks with too much time on their hands.

I did put the thread on 'Unwatch' but it has a strange kind of fascination for me. The stamina of the opponents, the spurious technicalities, the irrelevance to the real world. And most of all the way it has nothing whatever to do with the original topic . . .

Keep at it, lads! You must have plenty more to say!

 

[RichardS]

I think the mods should lock this thread as there is no more productive posts.

But nobody is being rude or abusive or threatening anyone or posting up private messages so I don't understand what harm the discussion is doing?

I assumed that it was dead but Convey wishes to revive it so where's the harm? Sometimes threads which are years old are revived but I've never seen the Mods wanting to do anything to stop them.

Richard

 

[rogerthebodger]

Here we go again.

Compression Ratio is the ratio of two volumes, the shapes are irrelevant.

I wouldn't call Wikipedia authoritative! It does give the formula previously quoted by Robershaw.

Been called many things Roger the dodger, Roger the Bodger, Roger the Lodger but never Rober but I don't take offence. It's probably a typo anyway.

You can also use the combined charles law and Boyle's law I posted early.

 

[RichardS]

Convey isn't contradicting himself, just wrong.

Indeed. Will we see an edit to #348?

Richard

 

[rogerthebodger]

But nobody is being rude or abusive or threatening anyone or posting up private messages so I don't understand what harm the discussion is doing?

I assumed that it was dead but Convey wishes to revive it so where's the harm? Sometimes threads which are years old are revived but I've never seen the Mods wanting to do anything to stop them.

Richard

I agree that nobody is being rude or abusive or threatening anyone or posting up private messages but is gone way off subject and is no more productive but its just my view and we all can have our opinion as long it not hate speech as you say.