The Restoration of the 40 Gaar Scott Motor

By: Lawrence Swanz

Zimmerman, MN






Washing the load - #1

Washing the load - #2

After driving across icy roads, the motor was covered with some of that good ol’ Minnesota salt…I washed it off, as the ol’ girl hadn’t seen salt in its 102 years of life…why subject her to it now!

It was one of those balmy sub-zero days the day I washed the load off…so consequently, there was a nice layer of ice that formed all around the iron…encasing it in a thick glossy shiny finish.



Lifting motor off of trailer

Unloading the crank and flywheel in my shop.

Easy does it…unloading the motor…



Setting the motor down onto its temporary heavy duty sawhorses and wood blocking.

Ready for tear down!  The motor took some time to melt off all of that icy finish.  The shop was like a sauna for a few days.

Motor on sawhorses - #1


Whew…I can breathe again!  The motor made it safely from Jerred’s farm to my house...and now the real fun can begin!



Removal of Right Hand Valve Chest Covers - #1

Removal of Right Hand Radius Link Assembly - #1

Starting the tear down!  Removed right hand steam chests…things are already looking good inside.

Removing Right Hand Radius Link Assembly.

Right Hand Valve Link - #1

Right Hand Valve Linkage Assembly Removed - #1

Right Hand Eccentrics and Radius Link Assembly removed.  The Right Hand Link Block appears to be in good shape and there is little to no slop noted in the Link Block and Pin.

Right Hand Eccentrics and Radius Link Assembly.  The pins in the Eccentric Straps to the Radius Link Assembly appear to be in good condition.  I will be checking them closer…later.

Removal of Left Hand Radius Link Assembly - #1

Removal of Left Hand Valve Chest Covers - #1

Due to -40 degree temperatures outside…Nicholas’s school was closed.  Therefore he was able to work in the shop with me over the course of the next five days…Thursday through that Monday…Martin Luther King Day!  We now call it, “Work on 40hp GaarScott Day!”

Left Hand side of motor…we bounced back and forth working on both sides for a while.

Left Hand Low Pressure Valve Chest - #1

Left Hand High Pressure Valve Chest - #1

Left Hand Low Pressure Cylinder Steam Chest

Left hand High Pressure Cylinder Steam Chest

Removal of Left Hand Cylinder Head - #1

Removal of Left Hand Cylinder Head - #2

Nicholas getting ready to remove the Left Hand High Pressure Cylinder Head.

Success!!!  Nicholas says!

Right Hand High Pressure Cylinder - #1

Left Hand High Pressure Cylinder - #1

Right Hand High Pressure Cylinder…look how good the cylinder looks.  But you can see where the cylinder was ran shy on cylinder oil, as you can see slight marks in the bottom of the cylinder where the piston and piston rings drug against the cylinder.  No physical damage noted in the cylinder…yeah!

Left Hand High Pressure Cylinder…This cylinder was getting good lubrication…you can still see the sheen of the oil still shining through.  That ol’ steam cylinder oil is some amazing stuff…fifty three years since the engine has had the stuff pulse through her veins!

Removal of Cylinder Petcocks - #1

Removal of Left Hand Valve Stem Assembly - #1

Nicholas is working on removing the High Pressure Petcock Assembly.  Too bad whoever was its prior mechanic/maintenance man, that they used pipe wrenches or hammer and chisel to loosen or tighten the various connections on the motor.  Especially when some of those connections were nice pieces of brass, like the unions on the petcock assembly.

Working on removing the Left Hand Valve Stem and Link Guide Assembly.

Removal of Left Hand Valve Guide Assembly - #1

Left Hand Low Pressure Valve Seat - #1

Still working on removing the Left Hand Valve Stem and Link Guide Assembly.

Left Hand High Pressure Cylinder valve seat…notice the Steam Cylinder Oil still sitting in the bottom of the steam chest.  Also, notice how nice the valve seat looks.

Left Hand High Pressure Valve - #1

Left Hand Low Pressure Valve - #1

Left Hand High Pressure ‘D’-valve

Left Hand Low Pressure ‘D’-valve

Left Hand Valves & Stem Assembly - #1

Left Hand High Pressure Valve Seat - #1

I had marked the location of the valves on the valve stem prior to taking the assembly apart.  I put them back together as they were inside the steam chests.

Another shot of the High Pressure Cylinder valve chest…with standing steam cylinder oil.

Removal of Left Hand High Pressure Cylinder - #1

Removal of Left Hand High Pressure Cylinder - #2

Setting up in preparation of removing the Left Hand High Pressure Cylinder.

Nicholas assisting by carefully driving a small chisel between the bodies of the High and Low Pressure Cylinders.

Removal of Left Hand High Pressure Cylinder - #3

Removal of Left Hand High Pressure Cylinder - #4

With the aid of this screw bottle jack, which I made back when I attended a machinist class during my high school years.  The bottle jack worked like a charm and easily pushed the two components free from one another.

Success!!!  Once again, Nicholas’s smile says it all!

Left Hand High Pressure Cylinder - #2

Left Hand Low Pressure Cylinder - #1

A shot of the High Pressure Cylinder side, which shows the rectangular chamber cast into it, which feeds the steam from the High Pressure Exhaust to the Low Pressure Cylinder Steam Chest.

A shot of the Left Hand Low Pressure Cylinder, High Pressure Piston, Intermediate Head, and Packing Gland assembly.  Also, in the bottom right hand corner of the photo is the matching rectangular chamber feeding directly to the Low Pressure Steam Cylinder Chest.

Left Hand Low Pressure Cylinder - #2

Left Hand Intermediate Head Assembly - #1

Removed the four bolts and cover plate of the Intermediate Heads internal Packing Gland Assembly.  From what I’ve learned, the Internal Packing Gland is a brass piece with five internal grooves, which catch and hold steam/cylinder oil.  Because the chamber (Intermediate Head) is slightly cooler than either the High or Low Pressure Cylinders, the steam condenses back into water and the water/steam cylinder mixture creates a water seal…yet it lubricates the High Pressure Piston Rod.  A perfect seal between cylinders!  Got to love that 1908 technology…and it worked!

Another shot of this area.  The cast “nose” of the Intermediate Head is an alignment piece, according to the literature, is supposed to give perfect alignment each and every time one has to remove the High Pressure Cylinder.  I suspect to mainly replace piston rings, packing gland or something along those lines.  Regardless, you have to once again marvel at the ingenious of the foresight to make such provisions.  You got to love those “Tigers”!

Left Hand Intermediate Head Assembly - #2

Left Hand Low Pressure Cylinder - #3

What the brass gland looks like….not much to it for what it does.

This photo shows the press fit of the Intermediate Head in conjunction with the Low Pressure Cylinder.  The Removal of the Intermediate Head caused some head scratching for Jerred, Mike McKnight, Rev. Jim Jake, and myself.  We spent some time trying to figure out how the head was held in and how to best remove it.


This ended our first day in the shop.  Although it was a long day, we didn’t shut the lights off till well after mid-night.  Good thing Nicholas’s school was closed the following day for the same reasons they were today…or his mother would have had words with me.  She thought we were nuts for staying up so late…but we were having such success, that we just couldn’t seem to stop!


Over the course of the next few days, Nicholas and I worked on the motor dismantling.  Here he is backing off the jamb nut on the Low Pressure Piston Rod.

Continuing his efforts!

Using the Port-a-Power to push the Left Hand Crosshead Assembly out.

The Port-a-power doing its job!

Success!!!!  It’s moving!

The Left Hand Crosshead Assembly.

It looks worse than it really is…with a little elbow grease, I’m sure these will clean up nicely.

After consulting with Jerred, Mike McKnight, and Rev. Jim Jake, we came to the conclusion that the head was a press fit.  Even though in one piece of literature it did reference set-screws aiding in hold the Intermediate Head in place, I found no such screws after removing portions of the old lagging and assumed asbestos insulation.  So with a small amount of force from the port-a-power pushing on the Low Pressure Piston Rod, using the Low Pressure Piston as a ram to push against the press fitted Intermediate Head, and the aid of a little heat… 

Wahlaa!!!!  She popped loose!

After the Intermediate Head popped loose, it was easily jacked out using the port-a-power…

As can be seen in this photo.  It would appear that only about an inch of the overall six inch deep Intermediate Head is actually used for the required pressed fit.

Here the Intermediate Head is fully out…and the Low Pressure Piston is on the verge of coming out itself.

Everything is coming out nicely.

Alas…here she is!

And here she is…success…we got it out.  That was a big learning curve on how to remove this large component.  Thanks again Rev. Jim Jake, Jerred, and Mike McKnight for taking all of my calls concerning the removal of this part.  Without having a good manual at hand…your insight was invaluable!

This is a shot of the Left Hand Low Pressure Cylinder.  It looks pretty good also.  But not quite as shiny as the Left Hand High Pressure Cylinder.  But not bad either.  There’s no physical pitting in either of the cylinders.  Let’s hope the other side looks as good as this side.

Now that Nicholas and I are past the learning curve of taking one side of the motor apart…the other side will be a breeze!

Getting things ready to remove the Right Hand High Pressure Cylinder.

The Right Hand High Pressure Valve Seat.  This one looks as good as the Left Hand High Pressure side.  Things are looking good yet.

The Right Hand Low Pressure Valve Seat looks about as good as the Left Hand side.  However, there are some rust marks on the valve seat.  Indications that the Right hand side didn’t get as much oil as the Left hand side motor.

Nicholas carefully driving a small chisel between the Low and High Pressure Cylinders.

This side went considerably easier and faster than the Left Hand side.  Once again, because we were able to repeat our successes…and not our failures.

Once again, with the aid of the port-a-power and some blocking, we were easily able to push out the Right Hand Crosshead Assembly.

Nicholas manning the port-a-power.  His five days in the shop with me in dismantling the motor were invaluable!  He was a great asset…and I hope he enjoyed the shop time as much as I did.

Right Hand Crosshead Assembly safely removed and resting on the floor.

A shot of our blocking apparatus, as I only have the one hydraulic body.  But with the aid of wood and steel blocking both, we had no trouble pushing out the second (Right Hand) Intermediate Head Assembly.

Success again!!!  The Right Hand Intermediate Head, Low & High Pressure Pistons all came out smoothly.

Getting ready to set the assembly on the floor…we are really gaining ground now!

Ahh Come On!!!!  Man what a disappointment when we got to see what the Right Hand Low Pressure Cylinder looked like.  Up until this point, everything we had removed off the motor was in pristine condition…bummed!

It ain’t so bad…after a quick brush of some 150 grit sandpaper, and she cleaned up pretty well.  There isn’t any real deep pitting, I’ve seen a whole lot worse…just bummed after the other three cylinders looked so good.

Here is a little closer shot after the quick clean-up.  Also, you can see small marking along the bottom of the cylinder from the Low Pressure Piston and Piston Rings dragging along the bottom due to poor lubrication.

You can see the shiny spots on the Low Pressure Piston.  Thankfully there is no scarring…just a shiny surface.

The same is visible on the High Pressure Piston…just not as prevalent.

This is a rear view of the engine frames still attached to the boiler castings.  I’m going to use these castings, once attached to an engine cart I’m building to move the motor around on, to keep things straight and in-line.

Right Hand view of Engine Frame

Left Hand view of Engine Frame


Front view of Engine Frame…she sure has come a long ways…now comes the slow part…cleaning her up, fixing what needs fixing, and then to start the re-building.

I hope you all have enjoyed the photos and the commentary as much as I have being involved in the project.


Finishing welding the engine cart before disassembling the two motor halves

Getting ready to lift the crank out and start separating the motor

Easy does it…there we go!

Removing the left hand main engine frame.  Was a little nervous.  Didn’t want to drop the massive chunks of iron on the floor.  Notice the chain securing the right hand motor while the left hand is being lifted away.

Swinging the six foot long left hand engine frame away.  This has to be the first time they have been split from each other since the factory…wow!

The two main engine frame castings that mount to the boiler.  I built the engine cart and leveled everything up before taking it apart.  I want to have a good stable foundation on which to reassemble the engine back onto…that is the plan anyway.  The center crank bearing support is mounted separate of the main engine frames and can and has been removed once before.  It will come off prior to blasting the boiler motor support castings.


Every once in a while I get Kara, my lovely bride, to come out and give me a hand.  Here she is cutting out wood cover plates to protect the machined surfaces of the various casting parts…thanks Dear!!!!!

Building a cradle to transport the crank to Lund’s Machine Shop…and then up to Jim Briden’s shop.

Couldn’t locate my babbit-rite, so used my son’s playdoe.  It works…and is kinda pretty to look at.

The saddle after the babbit was poured.


The right hand connecting rod completely taken apart.  Notice all of the shims!  There were about 3/16” worth of shims stacked behind the brasses.  Somebody got there wear and tear out of the old babbit inserts!

Eric Bolduc came out to give me a hand pouring new babbit inserts…to later be machined at Lund’s Machine shop.  Jeff has a mill with a rotating head.  So it works well for machining out the babbit inserts and the necessary radius on the babbit brass inserts.

The brass insert after the old babbit was burned out.

Making preparation of heating and removing old slag from the babbit prior to pouring.

Pouring the new babbit inserts.  We used a can to create the void.  It worked well.

Here is the pour…it looks rough, but is a good pour.  All of the excess babbit will be machined flush with the brass body

Here is one of the two halves poured

The crank is loaded and nestled securely in its transport saddle.  That morning I tested it too…was clipping along at 60mph traveling through the Twin Cities when the traffic went from 60 to 0 in less than 60 yards…give or take.  It was a quick braking.  I looked back as I stood on the brakes and she sat quietly there as we came to a quick stop.  Sure was glad I took the time to build the saddle.  She rode fine from my house to Jeff’s…and then from Jeff’s to Briden’s shop where Jim is match machining the newly cast crank pinion to the crank shaft.  I should have the crank and new gears back from Jim’s in a couple weeks.


Jeff setting up the first connecting rod in the mill.

After cleaning up the face of the babbit pour…we are making our first cut passes.  Besides the head rotating on a circle…it also steps down automatically.  It makes the job of match machining the brass inserts to the crankshaft a breeze.

A closer up shot of the machining taking place…boy doesn’t it look good!

After machining the bore out a few thousands over the diameter of the crank journal…we are starting to machine the relief radius.  We are almost done!




Well…I get to wear a little egg on my face.  When we took the brasses out of the connecting rod and tried them on the crank journal is when we realized the relief radius wasn’t to the size we had machined in.  We didn’t have the correct relief radius on hand.  So decided that we would be redoing the now finished babbited inserts at a later date when we could order the correct relief radius.  I had used a caliper to measure the height of the radius and assumed this to be correct.  However, after trying to fit the newly machined brasses we realized we needed a much larger one.  We will be checking the crank out with a set of radius templates to make sure we order the correct size…this time.


If this is the only hiccup we encounter on the project, we’ll be doing just fine.  But this fits into the ol’ adage…check your measurements twice and three times before proceeding.  Although I did check the height multiple times, it wasn’t the proper way to interpret what I was trying to achieve…live and learn they say.

The radius relief is almost done.  We have finished one side and are on the opposite side now.  About time to check our work.









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