Can somebody explain this phrase which I occasionally see on the listings for older EMDs for sale?

Thanks.

As far as I know, it means that it is a 567 engine with 645 power assemblies installed. I think that this was a fairly common upgrade to older 567 equipped locomotives. If you have taken a look at an EMD prime mover, the base block has the power assemblies attached that contain the cylinder, piston, rod, and valves.

Steve

Nailed it. Includes the cylinder liner, cylinder head, piston, rod, piston pin, valves, valve bridges, etc.

Probably more, too. A fairly simple upgrade, IIRC.

P.Cook will know this by heart, I'll bet.

So does that mean you have the locomotive equivalent of a bored out small block; in this case going from 8.5 to 9.0625 inches?

Assuming the answer to this questions is "yes", is the motivation greater displacement/power or something else like 645 packs being manufactured from more durable alloys, more parts availability or a combination of these reasons?

Don't know about alloys, but the other reasons are real.

567 parts have been scarce for years.

I believe that this modification was possible only when blocks were manufactured after a particular date - sometime in the late 1960s or early 1970s, I think. It had something to do with certain areas within the block being robust enough to take the additional stresses associated with the larger power assemblies. When we were looking for blocks for the six Maryland DOT (MARC) GP-39H-2s re-manufactured by Morrison-Knudsen from GP-40s, we had to check out the serial numbers of the blocks to make sure they were manufactured after that certain date. As somebody said, Preston Cook probably has the date on the tip of his tongue.

G.F.Payne
Baltimore, MD

MI 9547 covers the use of 645 cylinder power assemblies in railroad 567C, 567D, and partial conversion in certain other 567 engines that were previously rebuilt to "C" water manifold configuration (like the 567BC). MI 9601 covers the same topic for marine and industrial engines.

The upgrade allows the owner to use more readily available 645 parts and take advantage of product design improvements. It was not intended to bring 567 engines up to 645 power ratings, as the older engines are limited by their crankcase designs.

The manufacture date based upgrades George mentioned are the use of 645 "EB" and "EC" higher horsepower improvements in older production 645 engines. The use of these components is restricted by the manufacture date of the 645 engine crankcase, there were several effective dates assigned to different configuration 645 engines, most in the early 1970's, but some as late as the 1980's. They reflect the date that heavier crankcase components and welding were applied to the various engine configurations. There are actually five different dates involved depending on number of cylinders and desired power assembly usage, anyone needing the full details should contact the EMD Service Department directly for the exact effective dates of those changes.

PC

The ones I remember were when a number of roads turned 2,500 hp GP35s into
2,000 hp GP38s by removing the turbocharger and installing 645 assemblies. of
course, this would tend to lower the stress on the case and pan, rather than increase them.

That was also done by ICG, CNW, and others when they converted SD24s and SD35s into SD20s, again removing the turbos and derating the governors from 2,400 or 2,500 hp respectively to 2,000 hp. And 2,400 hp SD24s into 1,800 hp "SD18s."

On the other hand, IC/ICG and others made a lot of 1,500 hp GP7s into 1,600 hp GP8s
by installing 645 assemblies into totally rebuild 567 BC and C cases and pans, and even more 1,750 hp GP9s into 1,850 hp GP10s. Of course, that was not as much of a stretch, because it was only 50 hp more than the GP18 and GP28.

When UP starting cranking out SW10s from SW7s, SW9s and TR5s they used 645 assemblies but left the horsepower at 1,200.

The UP Sw10's were more than swapping power assemblies. The cooling system was better than original switchers so you could "get after it better" They used better injectors and governer. Another little trick I found was they used good old hot roding on the engines. The blower drive gear ratio was that of a high altitude 16cylinder ratio. I learned this after we had a failure and the traditional 12 cylinder gears didn't fit. When I found the right gears that's what they were.
This would explain why on the C block SW-10's we had I could get 1,400 H.P. on the load box the few times I had the money to rebuild one right.

Some of these engine upgrade and parts interchangeability and substitution issues would made good topics for discussion at an ATRRM conference sometime. That has been discussed in the past among some of the members of this forum.

PC

LIKE BUTTON!!!!

Seriously, there are few topics at ATRRM that have interested me lately.

Eric

Not a big surprise, since so many UP units did have to work at higher elevation,
such as Denver, Cheyenne, Laramie, etc.

So, the blowers were over-driven? I bet this didn't help the already-bad condition of parasitic drag on the EMD 2-stroke, the (highly inefficient) blower is the main culprit!

CD

I could be wrong but I think the IC/ICG "Paducah-bilt" rebuilt older Geeps were pure 567's and the modest increase in horsepower was simply a matter of governor settings with the freer 4 stack exhaust being one enabling factor.

They're already Roots-blown so it's not like the latter-day high horsepower 567's where you want to get rid of the turbo expense and I don't think you need 645 PA's to go up a puny 50 or 100 horsepower.

One high profile example of 645 PA's on 567 blocks would have been BN's (WSMTD) commuter E fleet, rebuilt in the early 70's by MK.

The Paducah rebuilds had 645 assemblies. Paducah shop had a very modern, automated line for rebuilding individual parts and putting them together as assemblies for installation in the rebuilds on the line, the 645 equipped units that came into the shop for heavy work, to be shipped to outlying shops, and for use in towboats.