567 and 645 engine

[Anonymous]

Hi

 When comparing roots blown 567 and 645 engines, I've noticed that 567 engine has a certain "chugging" sound, that 645 lacks.  It seems to me like 645 engines have a much smoother sounding exhaust, while 567 have this periodical pounding, or a very distinghuished exhaust note.

 I'm sure anyone who has ever heard a 567 engine, knows what I'm talking about

 

But I'm confused , because, I though there isn't that much difference between these engines, exept for larger bore diameter (even the stroke is the same) and that it is even possible to convert 567 to 645

 

So, does anyone have any idea what makes the difference in sound? Why  does a 567 go chug-chug-chug-chug under load, while a 645 goes more like a continuous thunder

 Is the sicret in exhaust manifolding? Or something else?

[Anonymous]

Hi

 When comparing roots blown 567 and 645 engines, I've noticed that 567 engine has a certain "chugging" sound, that 645 lacks.  It seems to me like 645 engines have a much smoother sounding exhaust, while 567 have this periodical pounding, or a very distinghuished exhaust note.

 I'm sure anyone who has ever heard a 567 engine, knows what I'm talking about

 

But I'm confused , because, I though there isn't that much difference between these engines, exept for larger bore diameter (even the stroke is the same) and that it is even possible to convert 567 to 645

 

So, does anyone have any idea what makes the difference in sound? Why  does a 567 go chug-chug-chug-chug under load, while a 645 goes more like a continuous thunder

 Is the sicret in exhaust manifolding? Or something else?

I suspect you're listening to normally aspirated (Roots-blown) 567s and turbocharged 645s.  There is not a large difference in sound between Roots-blown 567s and 645s, and turbocharged 567s and 645s.  There ARE differences in sound but they are more in the category of nuances.

S. Hadid 

[Anonymous]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

[Anonymous]

Hmm, well, I wasn't there and I have no way of knowing if the recording is a true and accurate representation of the real sound especially as it comes out of my computer speakers.  To me, it doesn't sound any different than any Roots-blown 645, and if you had told me it was a 567, I would have assumed it was that too.  645s do have a little more "bark" to them but it's not a large difference.

I used to fix these things so I'm very familiar with their sound. 

Beats me why one engine design sounds different than another.  I am aware of differences in bore, stroke, manifold, number of cylinders, etc., and I can even draw correlations.  In the field I can from experience tell without looking whether I'm listening to a 16-567C, 16-645C, or 16-645E, but how those differences cause the sound difference I do not know, and I don't wish to guess.

S. Hadid 

[Anonymous]

Well I'm not the first person to report that a 567 has a "chug", like a helicopter.

I've heard so many folks say that, that I considered it a kind of a "trademark" of 567 engines...

 

Here is a 16-645E for comparison. Now I can't say anything about realism of the first recording, but this one I made myself, and can tell you for sure that this is how it sounded, if you use headphones that is.

http://free-os.t-com.hr/redmist/2062kretanje.mp3

 

Notice how, when this one loads-up, it has a very different exhaust texture. You mentioned the word "barking", that's a good word, but I'd use it in reverse, I'd say the 567 barks in the first recording, while you can't hear the barking in this recording of 645. It's more of a crunchy sound that the exhaust of this 645 makes. 

 

[ed1205]

 The frist one sounds like it's coming from an SD unit the other sounds like a F unit. maybe the exhust is made differnt.

[Anonymous]

First is coming from a GP7, and the other one is coming from an export G26CW, which is like an SD unit with 4 stacks. First is a 567 engine, the second is a 645

 

Well, yea, the difference could be in the exhaust and not so much in the engine, but I'm still currious what that difference is

[oltmannd]

Could it be notch 8 engine speed?  Most 645E engines run at 900 RPM in notch 8.  567B and below run at 800 RPM and 567C at 835 RPM. 

I could always tell the difference between a 12-645E powered MP15 and a 16-567C SD9 by sound, but the difference was due mostly to the whine of the TM blowers on the SD9 rather than engine sound.

[oltmannd]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

Sounds like somebody needs to check the rack settings on the injectors.......

[Anonymous]

Now you've got me REALLY currious...

 

can you please explain that last comment?

 You mean, this is not how a 567 normally would sound? What do you mean by rack setting?

[jockellis]

G'day, Y'all,
I don't understand Mr. Hadid's statement that a normally aspirated diesel was Roots blown. If it is a Roots, it is a supercharger, isn't it. did Rudolph Diesel stick a Roots supercharger to the first diesel, thereby making the normal into a super or vice versa?

[Anonymous]

A supercharger fills the cylinder with compressed air. The roots blower fills the cylinder with near-atmosphere pressure air. It only serves as a "ventilator" that fills the cylinder with air because there is no intake stroke. 

Of course, the principle is the same, it's just a difference of how you set the compressor device, will it compress air , or just exchange it

 So in principle, a roots blower can serve as a supercharger, but in this case doesn't

There is only a small pressure difference to stop exhaust gasses from returning to the cylinder, but that pressure difference is not enough to be considered "supercharged".

 someone correct me if I'm wrong

But I'm still currious about this rack setting. I suspect Don ment the rack that rotates the gears of individual pumps that control the amount of fuel that is being injected. If that is so, I'm not sure what could this mean, that one of the gears skips a tooth and provides more fuel to one of the cylinders than the rest?? Is that what makes the chugging sound (one cylinder firing stronger)?

 

[silicon212]

Technically, a 'Roots blower' is a supercharger.  Even on high performance cars with Roots blowers,  the air is not compressed into the engine as a Roots blower cannot compress air.  It pumps air.

Although the Roots blower approach is considered to be, "Naturally aspirated" is not a correct term for the EMD 2-stroke engine, as this engine design simply will not run in a conventionally naturally aspirated configuration.  Hence the Roots blower or turbo unit.

Natural aspiration in the strict sense is the engine breathing on its own, without help.

[Anonymous]

Sorry about that, I thought the supercharger compresses air in cars. Don't know much about car engines.

[Randy Stahl]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

Sounds like somebody needs to check the rack settings on the injectors.......

Sounds right to me , Sounds just like a SW1500 !!!!! that is a 12 cyl 645. The GP 38 sounds a little tougher , with a 16 cyl , it ought to !!

[CNW 6000]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

Sounds like somebody needs to check the rack settings on the injectors.......

Sounds right to me , Sounds just like a SW1500 !!!!! that is a 12 cyl 645. The GP 38 sounds a little tougher , with a 16 cyl , it ought to !!

Just imagine what this sounded like!  3 of 'em, loaded train, plus uphill!

[Randy Stahl]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

Sounds like somebody needs to check the rack settings on the injectors.......

Sounds right to me , Sounds just like a SW1500 !!!!! that is a 12 cyl 645. The GP 38 sounds a little tougher , with a 16 cyl , it ought to !!

Just imagine what this sounded like!  3 of 'em, loaded train, plus uphill!

3 ALCo C628s were impressive also

[Anonymous]

It's a GP7 with 16-567B on the recording 

 

So can someone explain in more detail what that injector setting rack thing all about? 

I'm not asking for layman explanation, I'll do my homework, you can speak as technical as you will 

 

[coborn35]

It's a GP7 with 16-567B on the recording 

 

So can someone explain in more detail what that injector setting rack thing all about? 

I'm not asking for layman explanation, I'll do my homework, you can speak as technical as you will 

 

Sounds like our DMIR SD-18/M. It is not turbocharged. 

[WSOR 3801]

No, I'm comparing roots 645 with roots 567 (both naturally aspirated)

 

here is the sound I'm talking about:

http://www.yardoffice.com/RR/DieselSounds/Track15Sample.mp3

 

I've never heard a roots NA 645 load-up like that, it never sounds so "pulsating" 

 

I guess you could sort it under nuances, but what makes the difference? 

Sounds like somebody needs to check the rack settings on the injectors.......

Sounds right to me , Sounds just like a SW1500 !!!!! that is a 12 cyl 645. The GP 38 sounds a little tougher , with a 16 cyl , it ought to !!

Just imagine what this sounded like!  3 of 'em, loaded train, plus uphill!

I know what that sounds like.

3 SD20s would have been louder.  They have 4-stack manifolds, and a lot more smoke.

[oltmannd]

A supercharger fills the cylinder with compressed air. The roots blower fills the cylinder with near-atmosphere pressure air. It only serves as a "ventilator" that fills the cylinder with air because there is no intake stroke. 

Of course, the principle is the same, it's just a difference of how you set the compressor device, will it compress air , or just exchange it

 So in principle, a roots blower can serve as a supercharger, but in this case doesn't

There is only a small pressure difference to stop exhaust gasses from returning to the cylinder, but that pressure difference is not enough to be considered "supercharged".

 someone correct me if I'm wrong

But I'm still currious about this rack setting. I suspect Don ment the rack that rotates the gears of individual pumps that control the amount of fuel that is being injected. If that is so, I'm not sure what could this mean, that one of the gears skips a tooth and provides more fuel to one of the cylinders than the rest?? Is that what makes the chugging sound (one cylinder firing stronger)?

Exactly.  When you install injectors, you have to set the rack on each one.   The governor controls the fuel setting via linkage to each injector.  In the linkage to each injector, there is an adjustment so that each is injecting the same amount of fuel for a given governor rack setting. 

In practice, you jack out the governor quadrant to a specified setting and then use a tool to measure and adjust each injector.  If you leave one cylinder a bit "short" it'll "pop" a bit louder than the others. 

The rack on the injector rotates a pinion gear cut into the plunger in the injector.  The plunger is depressed by the cam through the "barrel".  There are helixes and ports in the barrel that determine when injection timing, both start and stop, as well as the volume of fuel injected.

On GEs, you have separate high pressure pumps and nozzles vs the unit injector on an EMD, but the parts and principles are the same.  On a GE, though the rack is spring loaded so that you can manually pull it out a bit on each cylinder and listen for the sharp "crack" of the cylinder firing.  If a cylinder sounds "mushy" then you most likely have a bad nozzle.

Some mechanics believe they can "tune" a GE by ear rather than using a rack tool - which probably explains why a lot of U boats out of Selkirk NY used to sound more like helicopters than locomotives.......

[Anonymous]

Thanks. I think that explains a lot, and I think it answers the question of the thread.

[broncoman]

I hope one of you guys may be able to answer this.  On detroit diesel engines (baby brothers to the EMDs)  GM switched from govenor control of injectors to a computer control of sorts (DDEC).  Did the big engines such as the 645s or upgraded 567s ever get computer controlling of injectors?  I also know when we rebuild 6v or 8v (53s,71s, 92s) detroits we check exhaust temp to make sure they are pretty close, is it the same for the bigger engines also?

And to add to the great explanation for the need of a supercharger on EMDs just to function normally remember that all EMDs with exception of the 6000HP "H" engine are 2 cycle diesels as opposed to 4 cycle like GEs.

Dave 

[Randy Stahl]

Correct on all counts

[miniwyo]

OK I am going to offer an idea from a non technical standpoint. Maybe they just different makes/models/aged engines. If you notice that a Ford Powerstroke, a Dodge Cummins, and a GM Duramax all sound different. Also Listen to a newer model truck and an older model truck of the same type, and they will have 2 very different sounds. I dont really see why this would be any different in Locomotives than they would be in Trucks. I may be just way off here, but I thought I would relate it as I didnt see anyone do that as an idea yet.

[silicon212]

What you hear in an automotive diesel, as well as trucks etc, is a production of those engines' relatively high compression ratio (18:1 and up), making that loud rapping sound that you hear.  Combustion chamber designs and layouts all affect the sound produced.

Locomotive diesel engines have lower compression ratios (12:1 to 14:1 is common in EMD, GE is close I am sure) and they don't have these nuances.  The combustion chambers on the EMD engines is pretty close to the same on all - 567, 645 have the same cylinder bore while the 710 has a somewhat larger bore.

Listen to a 16-567D3 (GP/SD35) and a 16-645E3(GP/SD40/-2) side by side - they sound pretty close.  The engine sound of a 16-710G3 sounds close to the earlier engines as well, but the turbo unit has a slightly different sound (more overtones).

The Roots-blown 567 and 645 engines do sound a little different - the 645 has more 'grunt' to it, but that can sometimes be hard to tell in a recording.  Of course, there is no Roots-blown 710 to compare to.

[snagletooth]

What you hear in an automotive diesel, as well as trucks etc, is a production of those engines' relatively high compression ratio (18:1 and up), making that loud rapping sound that you hear.  Combustion chamber designs and layouts all affect the sound produced.

Locomotive diesel engines have lower compression ratios (12:1 to 14:1 is common in EMD, GE is close I am sure) and they don't have these nuances.  The combustion chambers on the EMD engines is pretty close to the same on all - 567, 645 have the same cylinder bore while the 710 has a somewhat larger bore.

Listen to a 16-567D3 (GP/SD35) and a 16-645E3(GP/SD40/-2) side by side - they sound pretty close.  The engine sound of a 16-710G3 sounds close to the earlier engines as well, but the turbo unit has a slightly different sound (more overtones).

The Roots-blown 567 and 645 engines do sound a little different - the 645 has more 'grunt' to it, but that can sometimes be hard to tell in a recording.  Of course, there is no Roots-blown 710 to compare to.

Is it possible to make a normaly- aspirated 710? what would be the horse and who might buy it?

[silicon212]

They've never made a Roots blower that will run on it.  Theoretically, it is possible, but drawing from the 645, the 16-645E (Roots) produces 2,000 HP, while the 16-645E3 (Turbo) produces from 3,000 to 3,300 HP depending on governor settings.

 I would suspect a 16-710G (theoretically) would probably produce around ~2,800 HP.  The 16-710G3/A produced 3,800 HP, the  16-710G3B 4,000 and the 16-710G3C/T2 4,300. 

From Wikipedia, regarding natural aspiration in this design:

In order to allow the usage of a conventional oil-filled crankcase and pressure lubricated main and connecting rod bearings, a two-stroke diesel is scavenged by a mechanically driven blower (often a Roots positive displacement blower) or a hybrid turbo-supercharger, rather than by crankcase pumping. Generally speaking, the blower capacity is carefully matched to the engine displacement so that a slight positive pressure is present in each cylinder during the scavenging phase (that is, before the exhaust valves are closed). This feature assures full expulsion of exhaust gases from the previous power stroke, and also prevents exhaust gases from backfeeding into the blower and possibly causing damage due to contamination by particulates.

It should be noted that the scavenging blower is not a supercharger, as its purpose is to supply airflow to the cylinders in proportion to their displacement and engine speed. A two-stroke diesel supplied with air from a blower alone is considered to be naturally aspirated. In some cases, turbocharging may be added to increase mass air flow at full throttle-with a corresponding increase in power output-by directing the output of the turbocharger into the intake of the scavenging blower, an arrangement that was found on some Detroit Diesel two-stroke engines.

A conventional, exhaust-driven turbocharger cannot be used by itself to produce scavenging airflow, as it is incapable of operating unless the engine is already running. Hence it would be impossible to start the engine. The common solution to this problem is to drive the turbocharger's impeller through a gear train and overrunning clutch. In this arrangement, the impeller turns at sufficient speed during engine cranking to produce the required airflow, thus acting as a mechanical blower. At lower engine speeds, the turbocharger will continue to act as a mechanical blower. However, at higher power settings the exhaust gas pressure and volume will increase to a point where the turbine side of the turbocharger will drive the impeller and the overrunning clutch will disengage, resulting in true turbocharging.

[snagletooth]

  I've heard it would be difficult to build, something about the 710 that "needs" the turbo. Theorticlly, if they did, who might buy it? could they do a non Computer version for regionals at a reasonable price? Or is the SW/GP dead?

[silicon212]

I don't know when the SW/MP series was stopped, but the last big 4-axle EMD ever built _by EMD_ was the SP 9794, a GP60 delivered in 1994 (and incidentally, one of the only remaining unpatched SP units).

There is the GP20D, built under contract to EMD by MPI/Wabtec and based on a Morrison/Knudsen Rail design.  This is still available and looks something like a GP with a low long hood and lots of cockpit glass.  It's Roots-blown but I believe it uses a 16-645E engine.