Cass 6 Engine 
Part I - Overview
 Nelson Riedel, Nelson@NelsonsLocomotive.com
6/26/2004, last updated 08/23/2004

Heisler referred to the engine on their locomotive as the Motor, or Motor Engine.   This terminology must have been introduced by the marketing department when the engineers were all out to lunch.  I can't bring myself to call the engine the motor ---- I'd keep looking for the power cord.   (I am however able to put motor oil in my automobile engine.) 

 The Cass 6 Engine Description is divided into five parts as follows:

  • Part I - overview of engine. 

  • Part II - crankcase, crankshaft and bearings.

  • Part IIl - cylinders, heads, pistons and rods.

  • Part IV - rocker arm base plus rocker arms, valve stems and valve stem heads.

  • Part V - tumbling arm, reversing links, reversing link hangers and eccentrics straps.     

We start off with the most distinguishing characteristic of the Heisler locomotive -----the cylinders that stick out the side pointing up at a 45 degree angle.

Cylinders:  The next few photos were taken in the spring of 2003, after the boiler replacement but before the overhaul was completed.  This is the left side cylinder.   

The rod parallel to the lower frame bar is part of the linkage from the rear eccentric strap to the mechanical lubricator in the cab.
This is the right side cylinder.  The head cover is removed. Note the little snifter valve on the steam chest.  The steam supply enters the  side of the steam chest on the upper corner.  
The two cylinders are different!  Several times when looking at the right cylinder photos as well as the actual cylinder,  I was curious as to why the rectangular section between the cylinder and the steam chest was so long.   On the trip in June, 2004, I tried to measure the offset between the two valve stems as an easy way of estimating the offset between the two cylinders.  Surprise! The two valve stems are in alignment.  It was then I measured the two cylinders more carefully and found them different.   The rods are offset by 7" with the right rod further back.  The rectangular part of the right cylinder casting  is 7" longer to compensate. 

The composite photo on the right shows the right cylinder (upper) and left cylinder (lower) in a similar orientation.  The difference between the steam chest part of the two cylinders in obvious in this photo.   

Al Armitage's drawings of West Side Lumber Co #2 and Kozo Hiraoka's Heisler both have the two cylinders identical with the valve stems offset by the same amount as the cylinders are offset.    

Some of the photos in the Heisler Marketing brochure suggest that the change was made on the later heavier locomotives.  

      
Input & Exhaust Pipes: The next few photos were taken in June 2004 after the locomotive was completely reassembled and painted.   This photo shows that the steam input pipe entering the upper corner of the steam chest.  The exhaust  exits the cylinder horizontally, at  a 45 degree angle to the steam chest side rather than perpendicular so that it can pass under  the upper frame bar.
This photo shows how the exhaust is routed down and close  to the boiler so that it can pass between the frame bar and the boiler.

 

      

Crankcase:  This photo shows the rear side of the crankcase.   The crankcase is made up of two castings bolted together along the centerline.  The crosshead guides are part of the crankcase castings, one guide on each half. 

The small rod across the top is a link that connects the cocks on the two cylinders.

The small cylinder with tubes coming out the ends is part of the main bearing lubrication system.
Crosshead Guide:  This shows the right side crosshead guide and the attachment to the frame.  

That pipe with the wire or small hose coming out the end provides oil to the front main bearing. 
Upper Engine Mount: The upper engine mount is under the walkway so it is difficult to see and photograph.  This  photo shows the back end of the left cylinder mount.  The mount is bolted to a cast pad that is part of the cylinder.  The mount also bolts to the  upper frame member. 

 

Lower Engine:  This and the next photo were taken on July 14th, 2004.  I was better prepared this time --- I took a 3' X 5' piece of old carpet to lay on so that I could stay reasonable grease free while shooting under-the-locomotive photos.  (I was still covered with grease by the end of the day.)   This photo shows the under side of the crankcase, the main bearing caps and the lower end of the connecting rods. 
Lower engine mounting: this photo was taken looking straight up at the bottom of the left side lower engine mount.  The angle casting with all the bolts is on the outside and bottom of the lower main frame bar.  The crankcase mates with the top and inside of the frame bar.       

 

 

 

The drawing above shows the front view of the engine.  The larger arc represents the rear part of the boiler without lagging.   The smaller arc represents the smoke box diameter.   All the dimensions on this and the following drawings were checked on a second visit and  are reasonably accurate.  

The drawing above shows the top view of the engine.    

It was impossible to measure the thickness of the crankcase.   However, based on other measurements it seems to be 2 inches thick.    

All engine drawings can be downloaded from the  Drawings section. 

Model: The photo on the right shows a partially complete 1/4" scale model of a two-truck Heisler.  The cylinders and the valve mechanism were never finished. The crankcase and crosshead guides are similar to Cass 6.  This may help one visualize the drawings. 

A close look at each part of the engine begins in Part II ........    

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