I had a question come in this week about the exhaust manifold mounting on EMD 567A and 567B engines. The question related to water leakage around exhaust manifold mounting studs, basically asking whether the threaded stud holes pass through into the top deck water manifold.

Sharing the answer here for general information. Yes on the 567A and 567B the stud holes pass through into the top deck water manifold. The original engine assembly instructions call for the application of pipe joint compound onto the stud threads during installation. Also note that the compound should be applied to the hole threads far enough down to protect the full extent of threads on the stud. Water leakage along the lower threads may make stud removal difficult or cause damage to the threads on removal.

Also, for information, 567C engines in some EMD locomotives use the same exhaust manifolds as 567B engines used, but in the 567C it is secured by bolts rather than studs. On the 567C the threaded holes for the exhaust manifold bolts do not extend through into the water manifold.

Save the EMD manuals, pointers, and MI documents whenever you encounter them. The knowledge base on these old engines in the future will depend on what you save now.

PC

Good info. Thank you.

Didn't EMD develop a fix for leaks and then termed the revised engine a 567 B-C"?
Ned

That was leaks of a different sort -- not along the exhaust-manifold studs.

Note the importance of doping the full threaded length, not just to seal against leaks but to prevent corrosion of even a few threads at the 'waterside' that would make it tough to get the studs out without damage if desired...

The AC and BC (I've also heard of UC) rebuilds use C liners and add a water manifold in the airbox, just like a C or later engine. This was to eliminate the problem of water leaks at the bottom of the power assembly, on B and earlier engines the only seal between the liner and the block is a rubber o-ring, which doesn't seal tightly if the engine is cold or if the rubber is old and dried out.

A limited number of BC engines were built new during the production transition period.

I don't think anything on the top deck was changed on these engines, but I am not certain.

Exactly. You apply the pipe joint compound to the threads in the hole, down to slightly deeper than the threaded length of the stud, so that the stud pushes and compresses the compound down the threads. If you only applied compound to the stud threads, the compound near the front of the threads would be wiped away as it contacts the threads in the hole, leaving little compound to protect the threads nearest to the water in the manifold.

If questions of general interest on the early 567 engines come up, I will try to get them posted here and maybe also in the HRA technical library. The internet is by no means a permanent way to preserve the information but it is better than having it lost completely. Beyond that, it is up to the folks who have the engines to make and keep notes.

PC