Eastern Railroad Discussion > 645 power assemblies on a 567?

Loco experts:

When a locomotive is said to have "645 power assemblies added to a 567 engine," what exacly has been replaced? Anyone able to offer a description of what a power assembly is? Is this an indivual thing per cylinder or does this involve an entire "top of the block" type of change?

What are a result of this change? More horsepower, easier maint?

For an EMD, a power assembly consists of a head, liner and connecting rod. There are two types of connecting rods - fork and blade. The fork always goes on the left side of the block and the blade always goes in on the right side. An easy way to remember is fork and left both have four letters and blade and right have five (don't confuse left and right of the block with left and right of the loco unless of course the long hood end is designated as the lead). You wouldn't believe how many mechanics that work on these all the time don't know that. I've seen guys try to put 710's in a 645 a number of times only to find their mistake when the pa won't sit down in the block all the way. I remember when I worked for the NYS&W at Utica we overhauled the E-9's. I remember installing 645 D2 power assemblies in the process. I know from experience a 710 pa won't fit into a 645. But I beleive the 645 will fit the later model 567D? type block. The 645 and the 567D share alot of similarities, but since I never worked in a back shop I don't know exact measurements and models of which fits into which other than straight forward part for part. So long as the liner and head will fit in and sit at the same height as the rest of the cylinders, everything else will fall into place (the jewelry - rocker arms, injector, overspeed pawl). The one thing nice about EMD's is these items are usually interchangable to degree.

Cameraman Wrote:
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> Loco experts:
>
> When a locomotive is said to have "645 power
> assemblies added to a 567 engine," what exacly has
> been replaced? Anyone able to offer a description
> of what a power assembly is? Is this an indivual
> thing per cylinder or does this involve an entire
> "top of the block" type of change?
>
> What are a result of this change? More horsepower,
> easier maint?
>

csxchris already described what a power assembly is so I'll skip that. I think you can put 645 power assemblies in a 567C as well. You should get more HP since you're going from 567 cubic inches of displacement per cylinder to 645. I'm not a diesel mecahnic though, this is just information I've learned from working in a museum.

unless you soup up the Generator and Governor nothing happens.
The amount of fuel set by woodward governor decides how much hp your getting. and since the crankshaft etc are not upgraded you basicly only get a more fuel efficient and more modern 567.

csxchris Wrote:
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> For an EMD, a power assembly consists of a head,
> liner and connecting rod.I know from experience a 710 pa won't
> fit into a 645. But I beleive the 645 will fit
> the later model 567D? type block. The 645 and the
> 567D share alot of similarities, but since I never
> worked in a back shop I don't know exact
> measurements
OK so how is a 645 bigger than 567 the 710 has a longer stroke than a 645 is the 645 fatter but fits in a 567 ? Richard

The 567 is 8 ½" x 10".

The 645 is 9 1/16" x 10". The outer diameter of the PA remained the same (thinner water jacket. This is why it fits the 567 frame. (I presume you need to do something to up water flow through the narrower water jacket, particularly if you are going to a higher HP level.) A 567C frame is usually used but it can be done with a 567B using some sort of water jumper connections.

The 710 is 9 1/16" by 11".

Everyone probably knows this but for those who don't the engine series numbers 567, 645, and 710 represent the cubic inch displacement per cylinder of these engines. That means the volume contained within the cylinder and under the head with the piston at bottom dead center minus the volume remaining when the piston is at top dead center. By comparison a large automotive V8 (in pre-metric days) might have 455 or even 500 cubic inch displacement but that's for the entire engine and these numbers are per cylinder. So the 20 cylinder 710 on an SD80 has a total displacement of 14,400 cubic inches.

Thanks

Its not a hard conversion as its been done countless numbers of times over the years - some examples:

BN E8AU's/E9Au's

PC GP20M's

SP/SSW GP20E's - deturboe'd units

PNC GP20M's

SP GP35R's - deturboed examples

MP GP35M's

MP GP18's/GP28's

SP SD35R's - deturboed units

L&N SD35M's


B&O SD20-2's

NS SD9M's

FEC GP9's

ICG SD20's

CRR GP16's (ICG rebuilt units)

CR GP35M

BN GP39E's/GP39M's/GP39V's

ATSF SD26's

ATSF GP30U's/GP35U's

DM&IR SD9M's/SD18M's

MILW SD10's

CR E8AU's

CDOT FL9M's

SCL GP16's

etc etc etc

Larry

Cameraman Wrote:
-------------------------------------------------------
> Loco experts:
>
> When a locomotive is said to have "645 power
> assemblies added to a 567 engine," what exacly has
> been replaced? Anyone able to offer a description
> of what a power assembly is? Is this an indivual
> thing per cylinder or does this involve an entire
> "top of the block" type of change?
>
> What are a result of this change? More horsepower,
> easier maint?
>

There are EMD modernization recommendations to put 645 PA's in 567 engines. 645 PA's will fit in 567C and 567D crankcases without modification because the external dimensions of the assembly and the oil and water connections are the same. The 567B is very different, but there is what is called a "567BC conversion" that puts water manifolds in the airbox like later 567's and 645's and 710's have to get rid of the problematic O-ring water seals at the bottom of the 567B liner. As I recall, you still have to use a 567B head, because the top of the case is not changed. On a 567BC engine, you can use 645 pistons and liners, making a "645BC." For reasons noted by other posters, a "710BC" is out of the question. (And, yes, you can drop a 645 PA into a 710, but you won't be able to bolt up the water inlet jumper or the piston cooling tube because the connections on the liner will be too high.)

Because the 645 has higher reciprocating weight than a 567 does (it has larger diameter and heavier pistons), the counterweights on the camshafts also have to be changed to make the engine run smoothly. For the same reason, it's not a good idea to mix 567 and 645 assemblies in the same engine, though I've seen it done.

Though you can upgrade the power assemblies in 567's to 645's, EMD doesn't recommend increasing the power output to 645 levels because the crankcases won't take it. So the major incentive to upgrade PA's is to reduce the number of different parts that a railroad shop has to inventory and keep straight.

How does the cam shaft counterweight balance the pistons? Seems to me that's the function of the counterweights designed into the crankshaft.

Another reason to convert 567 PA's to 645's is that AFAIK EMD no longer makes the former so you can only get rebuilt. Unlike the latter which are probably better than originals what with laser hardening etc.

filmteknik Wrote:
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> How does the cam shaft counterweight balance the
> pistons? Seems to me that's the function of the
> counterweights designed into the crankshaft.

The crankshaft counterweights balance the rotating weight, the camshaft counterweights balance the reciprocating weight. (Actually, to get a little more technical, the camshaft counterweights are designed to compensate for the secondary imbalance caused by the up-and-down motion of the pistons not being completely sinusoidal.)

The pistons, piston carriers, thrust washers, etc. in the EMD engine move linearly up and down and are entirely reciprocating weight. The connecting rod is some of each; the pin end (and the pin that is bolted to it) is mostly reciprocating weight, and the crank end is mostly rotating weight. As a rule of thumb, a good starting point is that a connecting rod is one-third rotating weight and two-thirds reciprocating weight. It's more complicated in the EMD engine because of the fork-and-blade rod arrangement.

Interesting. By camshaft counterweight you mean those weights on the camshaft drive gears, yes? Odd that the forces involved in multiple cylinders with whatever the firing order is combine into something that can be balanced by weights on the cam shaft (granted the cam is turning at 1X speed).

filmteknik Wrote:
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> Interesting. By camshaft counterweight you mean
> those weights on the camshaft drive gears, yes?
> Odd that the forces involved in multiple cylinders
> with whatever the firing order is combine into
> something that can be balanced by weights on the
> cam shaft (granted the cam is turning at 1X
> speed).


Think of it as a misplaced harmonic balancer...

Some Japanese automobile engines ( like the new Nissan QR ) actually use balance shafts to do this...

Some older ones use the oil pump drive shaft to do this ( Toyota M series )...