567 and 645 engine

[rvos1979]

There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.

Dave

I can back that up. I have seen them running in high throttle powering locals around Fort Worth, TX and they have to be the loudest EMDs I have heard.

I third it, I can remember seeing and hearing the ex-MoPac GP35ms the Wisconsin Central had.  Some crews nicknamed them Harley-Davidsons (and everyone knows what Harleys sound like!!!)

[Anonymous]

  There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.

Dave

I can back that up. I have seen them running in high throttle powering locals around Fort Worth, TX and they have to be the loudest EMDs I have heard.

[bogie_engineer]

The difference in sound of 567 roots blown engines versus roots blown 645's may be explained by the difference in the exhaust manifold design.  Once the 567 engine had a top deck like current 567-645-710 engines instead of the prior U-deck as it was called IIRC, the 567 engines got what were called at EMD Vee leg manifolds.  The manifold chamber is a 15" round cylinder and the Vee leg manifolds had connecting pipes to the top deck flange, where they bolted over the exhaust outlets, that connected tangentially to the barrel of the manifold.  So as a cylinder fired, its mate accross the engine that fired 45 degrees of crank rotation later caused an opposing swirl in the manifold chamber.  On GP's and SD's with 8 or 16 cylinders, the manifolds were made in assemblies that covered four cylinders, two opposing pairs in the engine.  Two manifolds were joined by an 10" diameter tube with a band clamp to seal it.  Only one of the pair of manifolds connected together had an exhaust stack, the typical oval shape about 4" by 12".  The location of the stack depended on the dynamic brake arrangement, whether none, GP or SD.  On the SD with Dyn Brk, the stacks were at the very ends of the engine.  When an non-DB and on GP's, the stacks were over the cylinder pairs one in from each end of the engine. 

When the 645 was introduced, the manifold legs were made parallel so they wouldn't created the opposing tangential flow, otherwise they were the same.  This applies to the standard manifolds, which were non-spark arresting.

Only a few customers, most notably the MoPac, got non-spark arresting manifolds.  But MoPac got a special arrangement on their GP38-2's that had 4 stacks, one on each manifold, but two manifolds were still interconnected with the band clamp tube arrangement.  MoPac developed their own spark arrester which was a screen box that they mounted on the loco roof, one over each stack outlet.

Most customers of 645 engines got spark arresting manifolds that differed still in design.  These manifolds had a special leg arranged so both cylinders opposite each other caused a tangential flow in the manifold in the same direction.  These manifolds had a spark trap that captured by centrifugal action carbon particles that otherwise would exit the stack and possibly set wayside fires.  The US Forest Service has a performance test for spark arresting devices that must be met to operate thru national forests.  The bottom line is that all the class 1 railroads applied spark arresters of the EMD design or competitors designs such as the Heaton spark arrester used by MoPac or spark arrester manifolds made by the Farr Co. or others.

Most switchers used 8 or 12 cylinder engines.  The 8 cylinder arrangements were just half of a 16 cylinder set but with the stack changed to a tapered round instead of the straight oval.  12 cylinder engines got special manfolds that covered 6 cylinders each with no interconnecting between manifolds and round tapered stacks.  Silencing manifolds were basic on switchers and spark arresting were optional.

When the 1980 noise regulations for locomotives went into effect, EMD released a new set of manifold designs that differed significantly in that they were both silencers and spark arresters in piggyback chamber arrangement covering 6 cylinders in each.  On 16 cylinder engines there was a small manifold covering the middle 4 cylinders with pipe connections at either end to the larger manifolds.  All had round, straight stacks.  Swithers used the same manifolds as GP's and the result was a raised portion on the hood that covered the taller manifolds.

E units used an entirely different arrangement where all 12 cylinders were connected in line and exited the end of the manifold at the governor end of the engine into a 90 deg elbow with a pipe thru the loco roof so there was just one stack per engine.

My point in all this is that it would be amazing if they all sounded exactly the same since there are a range of manifold types that have a huge effect on the sound created when all cylinders are coupled into them.  Some were silencing types, some not; the Vee leg are different than the straight leg.  The retrofit of most locos with spark arresters from numerous companies has a huge effect.

This discussion completely ignores the changes that were going on in the engine that effect the sound produced.  Fire ring pistons, injection timing and duration, peak pressure, cam design changes, etc. 

I was the sound engineer at EMD during the 70's.  I designed the spark arresting-silencing manifolds that became standard in 1980.  I was resposible for all locomotive sound measurement.  There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.

Dave

[Anonymous]

I just watched the local shortline with is x-B&O GP 9 roll past the other day and it didn't sound any different to me than a GP38. The recording you have has a little different sound but it sounds to me like it is caused by the exhaust system. I do think however the the 567 has a louder whine (the higher-pithced sound from the engine not the stacks) than a 645.

[Redwood Chopper]

Normal aspiration exhaust versus turbocharged aspiration exhaust on any diesel prime mover makes all the difference. I never though I'd miss the sound of a hard working EMD 645, but that I do miss 'em nowadays means I've become a greybeard for sure. As for missing the wonderful "chant" [thanks to the late Trains mag editor David P. Morgan for that perfect descriptive] - I can't begin to say how much I miss that distinctive EMD first generation sound. I also miss the fantastically whacky syncopations of Baldwin diesels (with their de La Vergne prime movers) and even earlier GE U-boats... Yup, I'm a greybeard!

 

[zardoz]

The E-8's we used to use in CNW commuter service (twin 567's) had a real cool sounding harmonic when in the 5th notch cruising at speed;  the sound was a low-frequency rumble-vibration that occurred about every second.  It sounded (and felt) cool both in the cab as well as 1/4 mile away.

[Anonymous]

To me, the two normally aspirated engines sound so much alike that about the only difference I can notice is that the 645E sounds a little smoother other than that, the two sound very much alike. That is what Burlington Northern got when they rebuilt the E9 commuter diesels with 645 power assemblies applied to the 567 blocks and yet retained that familiar chant so characteristic of the pair of 567s each of these units came with originally. I am not sure if the CNW did this on their E8s but I remember the CNW E8s having a throaty roar sounding much like a GP39 accelerating when starting from station stops.

[Anonymous]

I've slowed down the recording of that chugging engine, and here is what I was able to hear

 

there is a repeating period of 8 beats, and one of those beats is so loud that it makes the whole engine sound like it's the only cylinder that's firing.  

 It goes like this

 

1 2 3 4 5 6 7 8  

 

the big 5 is the sound you hear at normal speed of the sound file.

 

It's so dominant that you can't even hear the other beats unless you show down the recording and increase volume in an editing program.

 

I guess this proves what Don was saying. This can only be a dominant engine. 

 But I think the alternate explanation is a hole on the exhaust manifold of one of the cylinders 

Now that I think about it. I've heard some buses that sounded like that. But that was a manifold rapture, at least I think it was. Could be the same injector misadjustment though as on these locomotives.  

 By the way, how do you call such a phenomenon?  I tried googling for "dominant cylinder" or similar phrases but found little results. There must be a common technical term for such a thing

 

 

[oltmannd]

  I really need to start another thread, but don't know how. It seem's to me the 40 series and even the 50 series are worn out and probbly not up to their full horsepower (justy an opinion, and I know what an opinion is worth), but an SD70 on an grain elevater in 2030 is just  unrealistic. I'm not talking about now, I'm asking about 20-30-40 years from now. if i should start another thread, please let me know how , I think this is worth a nother disscusion. But to getg back to the original topic, YES, I DO NOTICE A "SLIGHT" DIFFERENCE BETWEEN A 567 AND A 645. VERY SLIGHT!!!

A locomotive doesn't "wear out" like a car.  A 30 year old SD40-2 in line haul service has probably been through a half dozen engine overhauls (about half of them just power assemblies) and a dozen or so injector change-outs.  Even at the wear limit, the diesel engine will still make rated HP and fuel efficiency.  The easiest way you can tell that an EMD engine is healthy is to look at the stack after it's been running notch 8 for 5 or ten minutes.  If it's clear, then the engine is healty.  If there is any trace of black, then somethings not quite right. 

You can keep any locomotive going indefinitely as long as you can get parts for it.  What causes you to replace one model with another is strictly economics.  It's hard to justify replacing a GP38-2 or SD40-2 in yard or local service because they are so cheap to keep.  As long as you don't run into EPA regs or use them in a service that burns a lot of fuel, there's no reason these models won't be around for another 50 years.

An SD50 is such a complicated nightmare electronically and the F3 engine is such a pain, that it'll probably be cheaper to keep SD40-2s for yard & local service than modify SD50s.  SD70s with radial trucks might just find a long life on twisty coal branches and in mountainous pusher service.  It would be hard to use them in yard and local service because of their cab.

[Anonymous]

I was just wondering. That "helicopter" sound of "untuned" injectors that was mentioned earlier. How come it doesn't happen as often on read vehicles, like trucks. Is it something about the GE and  EMD engines that make them more vunrable to this issue?

And why do SW-type switchers always sound like that? I mean it can't be a malfunction or misadjustment, it must be something inherent. Or do they work on lower RPM than road switchers?

[snagletooth]

  I really need to start another thread, but don't know how. It seem's to me the 40 series and even the 50 series are worn out and probbly not up to their full horsepower (justy an opinion, and I know what an opinion is worth), but an SD70 on an grain elevater in 2030 is just  unrealistic. I'm not talking about now, I'm asking about 20-30-40 years from now. if i should start another thread, please let me know how , I think this is worth a nother disscusion. But to getg back to the original topic, YES, I DO NOTICE A "SLIGHT" DIFFERENCE BETWEEN A 567 AND A 645. VERY SLIGHT!!!

[WSOR 3801]

We switch with SD40-2s all the time in Janesville.  In Horicon, it has been done, but the curves in the car shop area are pretty tight for such a big motor.  There, a GP7 with working switch mode does pretty good.  Our best running GP38s are the ones that are deturbo'd GP40s.  Maybe because they are heavier.

The GP20D uses a Caterpillar engine.

Alcos and FMs are still made as well, they are popular in marine applications.   

 

[snagletooth]

  I hope and pray. I love non-turboed EMD's. grew up in Auroa with "J" SD38's, BN SD7's and 9's adding horse on the Ottowa turn (Love those SD45's waiting till they got to the tower to rev up after idling all night), The SW 1000's, 1500's and 12(00)'s working the Nephi branch ( I grew up 2 blocks from Barber- Green), and Beacon News doubled up (to deliver two boxcars?), and of course the E's. Oh my God, the E's in the mornin'. Idling all night. the Smoke would bury the town for an hour or two. You could here them at my grand father's house in Sugar Grove on a summer night. I thought they were monsters attacking when I was a child, the RRUMPP, RRUMPP, RRUMPP. To get back on topic, they deffinenty sounded different when they rebuilt them with twin 645's. Can't explain how, but deffinently a different sound.

[silicon212]

Well, switching with 6-axle units is not often done, but back in the early 90s, the SP Magma Turn local would sometimes run SD45s or SD40-2s - once even a GE C40-8. Normally the alloted power was an MK rebuilt GP40-2. The 645 engine is still very much alive and EMD continues to build it.  As for the 567 - if you have a "C" or "D" crankcase, you can replace the power assemblies with 645 power assemblies and have a "645C" or a "645D".

A lot of GP40 class engines have had their turbos removed and replaced with Roots blowers, making 'de-facto' GP38 class engines (GP38-2 or GP38-3).  BNSF recently acquired some old GP35 hardware that had power assemblies replaced with 645 parts and deturbo-ed, these are considered "GP38-3s" as well.

These engines will continue to run, it wouldn't surprise me to see a GP7 doing yardwork 30 years from now.  By then, these units will be 80+ years old!  Remember, there is a large aftermarket for EMD powerplants - even General Electric rebuilds EMD units and offers EMD replacement parts including power assemblies.

[snagletooth]

 I'm Sorry, I know I derailed the subject. But this does bring to mind an article(in Trains, I believe) about regionals and shortlines in 20-30 years if noone is building cheap locomotives. I can't imagine the local grain Op. switching with an old SD70 or EC40(?)(sorry, I'm a 70-80's type if I'm wrong on Des.) and the Alco parts are about run out and it's only a matter of time before the 567 and 645 parts are gone. I was just wondering while we were on the subject on the future of small locos. maybe I should start another thread on this?

[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.

[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]

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]

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]

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.

[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.

[Randy Stahl]

Correct on all counts

[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 

[Anonymous]

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

[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.......

[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.

[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. 

[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 

 

[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