Running engine (diesel) with the ignition turned off

[PaulRainbow]

You keep throwing insults up, but not actually substanting or counter the statements.*

You keep avoiding answering questions that was expose your lack of knowledge.

I'd like to see you measure it in any other way.

In short, you're only impressing people who have not got a clue about what's being spoken about.


My boat versus your boat in front of a third party expert at the IMechE any day you want ...

--

* (If you're now going to change discussion from simple deck height to the full block deck height, that's a separate issue. In practise, you wouldn't and couldn't do it)

I said ""deck height" and "squish" have now been thrown into the mix. Deck height is simply the distance between the top of the piston (at it's perimeter in the case of dished or domed pistons) and the surface of the cylinder block."

You replied "I presume you're reading the stuff about deck height and squish at the perimeter off a website ... because it's also crap. Deck height and squish are measurements right across the piston and wherever the face of the head exists."

And where is the measurement in your picture being taken ?

Exactly where i said.

My boat versus your boat in front of a third party expert at the IMechE any day you want

How old are you, five ?

 

[Max Campbell]

Following this thread for entertainment value, I've got to say, Convey, that you've lost. I can tell when bluster is being used as smokescreen.

 

[RichardS]

Your picture clearly illustrates beyond doubt why you rightly accused Paul of talking "crap" when he said that deck height is simply the distance between the top of the piston (at it's perimeter in the case of dished or domed pistons) and the surface of the cylinder block."

On the other hand, it possibly clearly illustrates that you have a screw loose somewhere.

Richard

 

[black mercury]

You keep throwing insults up, but not actually substantiating or countering the statements.*

You keep avoiding answering questions that was expose your lack of knowledge.


I'd like to see you measure it accurately in any other way.

In short, you're only impressing people who have not got a clue about what's being spoken about.

What's offensive is that muddying up the waters and discrediting what's absolutely true.

My boat versus your boat in front of a third party expert at the IMechE any day you want ...​

--

* (If you're now going to change discussion from simple deck height to the full designed block deck height, that's a separate issue. In practise, you wouldn't and couldn't do it accurately).

Hope that engine is for training purposes only and is not expected to be used. Or is that one you are rebuilding?

 

[rogerthebodger]

My boat versus your boat in front of a third party expert at the IMechE any day you want ...​

I said I would I you just need to arrange the meeting. I even told you where IMechE is located.

Are you a member of IMechE I used to be before I stopped practicing Mechanical design professionally and started designing control and application computer.

There are others on here who are Chartered Engineers but I am sure they don't wish to waste their time

Interesting I would not use a dial indicator to do that measurement, I would use the proper tool, a depth micrometer

This one is from cromwell tools

Or if you don't know how to read a micrometer you could use a digital depth micrometer

 

[RichardS]

Interesting I would not use a dial indicator to do that measurement, I would use the proper tool, a depth micrometer

The dial gauge might be being used simply to determine TDC ..... but what do I know?

Richard

 

[black mercury]

The dial gauge might be being used simply to determine TDC ..... but what do I know?

Richard

You're absolutely right.
In the image posted by convey you certainly would not be using that position on the piston to measure deck height.
As you say Richard it's only being used to determine TDC.

 

[rogerthebodger]

The dial gauge might be being used simply to determine TDC ..... but what do I know?

Richard

Any skilled technician should be able to determine TDC simply by placing your finger across the top of the block and piston.

In fact to measure the deck height all you need is a straightedge and a set of feeler gauges

 

[penberth3]

Are you still there Convey?

I'm still waiting for a brief "CV". Genuinely interested where your engineering knowledge has come from - you've thrown in a few terms that aren't in my everyday vocabulary.

 

[convey]

In fact to measure the deck height all you need is a straightedge and a set of feeler gauges

You're not going to get the same accuracy and struggle with domed pistons. And why bother if you can just drop a micrometer on it?

 

[rogerthebodger]

You're not going to get the same accuracy and struggle with domed pistons.

A skilled technician/ mechanical fitter with experience would easy be able to get the accuracy required and would easy be able to workout how to measure with a domed piston using slip blocks/gauge blocks. Any one who has been in a metrology lab would know that.

And why bother if you can just drop a micrometer on it?

So you agree with me that a micrometer would be better than a dial gauge in this case as I said in post #285

 

[convey]

Any one who has been in a metrology lab would know that.

What's a Metrology lab, part of the Rover Group plc?

"proper tool"

How is that a better tool? Perhaps you mean the "older tool" before micrometers and CNC pieces became so cheap?

I mean, those date back to when you had to make your own before using them. Like I did.

No, actually, because the bridge I use/made doubles up to clamp the cylinder/s down in place, which is obviously essential if the block is not one piece. I think you may have difficulty getting a read of some domed pistons I've seen.

You're just getting into silly point scoring - and still losing - to try and distract from the original discussion now.

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.​

Have we established a consensus about that yet? If yes, I'm happy to move on.

 

[convey]

And where is the measurement in your picture being taken ?

The measurement in that photo is being taken at the edge, but the dimension relates to the top face of the block/cylinder and, hence, exists right across the piston/hole.

Correct me if I am wrong.

As I wrote, even if the piston was domed above it and impossible to measure with a depth guage.

Do you understand the difference? It's a question of precision in your comprehension and what your saying, otherwise it becomes misleading.

Deck height does not just exist at the edges, true or false?

 

[VicS]

What's a Metrology lab, part of the Rover Group plc?

metrology .... the science of measuring.

In more detail , from the OED:

The study of systems of measurement; the science of measurement; the branch of technology that deals with accurate measurement.
1816 P. Kelly (title) Metrology; or an exposition of weights and measures.
1846 G. Grote Hist. Greece II. ii. iv. 425 M. Boeckh's recent publication on Metrology.
1878 Nature 23 May 110/2 Mr. W. M. Flinders Petrie read a paper on inductive metrology, the purpose of which..is to deduce the units of measure employed by ancient peoples from the dimensions of existing remains.
1925 Proc. National Acad. Sci. U.S.A. 11 359 Measures of light, or of energy generally, are among the most difficult and unreliable in the whole field of metrology.
1969 Physics Bull. Sept. 365/2 A large proportion of conference participants deprecated the term ‘measurement science’ and the use of the term ‘metrology’ appeared to have a large measure of support.
1993 R. J. Pond Introd. Engin. Technol. (ed. 2) v. 107 A metrology laboratory provides transfer standards or primary standards for each base unit listed

 

[convey]

metrology .... the science of measuring.

It was a joke. Rover Group plc used to make the Austin Metro. Austin Metro ... Metrolab ... I thought it was funny.

How are we doing on the compression ratio, or should I jusy say, "flame front"? Another pun, just in case someone's not paying attention.

 

[rogerthebodger]

What's a Metrology lab, part of the Rover Group plc?

That tells me how little you know about Engineering if you don't know what a Metrology lab is.

Metrology Lab | University of Strathclyde

Funny you would make a comment about the Rover Group plc. and Metro.

Most of my family was involved (worked) at Rover motors at Longbridge for many many years from my uncle's, Cousins and husband of my niece works aar Rover in Solihull and brother worked most of his life for Austin, then BMC, then BLMC, then Rover before the chinese moved the factory to china and sold the land.

I also project managed the Mini Metro the body in white build line also at Longbridge when I lived in the UK

How is that a better tool?

What is a better tool. Anyone who knows what he is talking about would use the correct tool for the job amd as I said a depth micrometer is the correct tool unless you have a err Metrology lab with a CMM Measuring Machine

Perhaps you mean the "older tool" before micrometers and CNC pieces became so cheap?

older tool well the first ever micrometric screw was invented by William Gascoigne in the 17th century, as an enhancement of the vernier

So a vernier is even older.

I purchased my first micrometer is a Moore & Wright and I still have and use it

No, actually, because the bridge I made doubles up to clamp the cylinder/s down in place, which is obviously essential if the block is not one piece.

Why does the cylinder need to be clamped down to measure the what you call the deck height and why would the block not be in one piece even on a radial engine each cylinder block iss in one piece where the head sits ?

You're just getting into silly point scoring - and still losing - to try and distract from the original discussion now.

Well I think as others do that suffer from Kruger Dunning syndrome. Look it up

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

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We have told you several times how a CR of a piston engine is calculated.

How you determine the V_c depends on the detail design of the engine. You keep on about the deck height (distance between the to of the piston on the top of the engine block at TDC is one of the factors but most production vehicle engines just don't have a deck height. The thickness of the head gasket does as does the shape of the crown of the piston and the volume of the head combustion chamber unless the head is a flat head.

BTW I would not willingly fit shims between a engine head and the block to alter the compression ratio

Have we established a consensus about that yet? If yes, I'm happy to move on.

The main consensus that we all have come too is that you either don't really know what youre talking about
Or You are just craving attention.
Or your ego is compelling you to try to prove how sureriour your are.
Or maybe you have been in a meth lab rather than a metrology lab.

 

[rogerthebodger]

It was a joke. Rover Group plc used to make the Austin Metro. Austin Metro ... Metrolab ... I thought it was funny.

Well that settles it you must have been in a meth lab


BTW it was BLMC not Rover as Rover only took over when British Aerospace gave up as they did not know how to run a car company.

 

[PaulRainbow]

You're absolutely right.
In the image posted by convey you certainly would not be using that position on the piston to measure deck height.
As you say Richard it's only being used to determine TDC.

How funny is it that Convey posts a picture that he claims shows how to measure deck height, where it's being measured in the wrong place ? ? ?

 

[convey]

You just starting to look embarrassing now, Paul.

Sorry, scratch that. You've been looking embarrassing for some time now and adding no value to the discussion.

Fair enough, British Leyland (1980–1986), Rover Group from 1986 to 1998 but that would kind of spoil the punchline.

Still point scoring? I'm the only one who's getting the tech right, and making intentional jokes.

How you determine the V_c depends on the detail design of the engine.

Yes, precisely .. BY THE SHAPE OF THE PISTON AND CHAMBER. It's not the "design of the engine". It's the design of the pistons and chamber (valves included).

As to the "most engines" don't have an additional deck height, you'll find that very hard to substantiate in real life. Especially given that we've talking of about at least 60 years worth of engines still in regular use.

Why does the cylinder need to be clamped down to measure the what you call the deck height and why would the block not be in one piece even on a radial engine each cylinder block iss in one piece where the head sits ?

Are you serious?

I have a 1958 MD beside me and even it has a separate cylinder. How many have one piece, how many are two piece ... who knows. Both exist.

Do you really need me to spell out why you need to clamp the cylinder block down to get an accurate deck height reading? Tell me if I do and I'll explain why for you.

 

[PaulRainbow]

Still point scoring? I'm the only one who's getting the tech right.

Clearly deranged.