IndianaRog and the Temple of Steam

The engine pictured above is a restoration and conversion of a late 1960's Jensen Model 50 engine into a replica of a Model 51, Jensen's top of the line flagship steam engine. 

The Model 51 and the Model 50 at it's core, are huge by toy steam standards and really more closely fit in the machinist built category, with each getting lots of TLC as they are individually assembled.  As compared to a standard Jensen Model 50, the  51 adds a functional water tower, a control box with line voltage AC, low voltage AC and low voltage DC switches and analog metering. 

In addition, the factory Model 51 adds a unique combination AC/DC generator capable of making low voltage AC to power the single lamp post or DC to power the small DC motor with mounted saw blade for visual effect.  Add a working condensate stack to route the exhaust to, mount it on an even bigger base board and voila, you have a Jensen 51...a bouncing baby of 75 pounds give or take.

I know of only two websites on the internet where you can see photos of a factory built Jensen 51:  The Steam Gallery and Jensen Mfg. Co. themselves.  For additional technical detail not covered here, both of these sites are well worth the visit.  

Pictured below right is the Model 51 as featured on the Jensen website.

Unfortunately, for many years now Jensen has NOT manufactured either the Model 50 or the Model 51 for sale to the collector market. 

This leaves the avid Jensen admirer to constantly monitor eBay for the rare emergence of a Jensen 50 someone is willing to part with.  I have seen only 4 show up in as many years and none of the Model 51.

For Jensen 50/51 owners, history buffs or those just interested in the many variations of these two models from their inception, the following summary was put together by two of the most knowledgeable Jensen collectors in the world...Bill Wheeler and Gil Garceau.  These gentlemen have graciously allowed me to post it here:

Click here for history and variations of the Jensen Models 50 and 51

My original Jensen 50 used as the basis of this project appears to be sort of a transition piece between Type 4 and Type 5 noted in this document, having some of the former and some of the later's features.  This is not uncommon for Jensen as Tom Sr. would frequently experiment and the results of those efforts brought about the next variation in a long progression.

In total Jensen manufactured between 250 and 300 total Jensen 50's.  It is believed about  27 were further developed into the Model 51.   Three private collectors I'm aware of are in possession of a total of 5 Jensen 51's...the original "prototype" built in 1977, three Jensen built "production" units and the latest Jensen iteration dubbed a "50 1/2" by it's owner (unique in that it was built by Jensen with a water tower, but no control panel).  The location of the remaining 51's is a mystery, but many original buyers were supposedly electrical utility companies and Universities which may well have them still in use for educational purposes.

Having made contact with other Jensen 50 and 51 owners was key to helping solve a feedwater pump problem I was having on my replica.  If any additional owners of a Jensen 50 or 51 are reading this, we'd love to make your acquaintance.  Please drop me a line at the email address on the bottom of the home page, maybe we can collectively help one another as well.

What follows here is heavily focused on my Jensen 50 restoration and 51 replication effort, as much to document it for my own satisfaction as well as for the curiousity of other steamers.  I didn't replicate perfectly as parts availability was a roadblock for some components, but I got the "look" and functionality close enough for government work!

As luck or good Karma would have it, in February 2006 I found a Jensen 50 for sale on eBay.  It looked to be of late 1960's vintage and as the story goes it was the demonstrator once used by a Jensen sales representative in the Western U.S.   I didn't hesitate to buy, despite some obvious corrosion visible in the pics, especially on the boiler face. 

Here is how my Jensen 50 looked upon receipt in Feb. 2006:

Despite being a little rough, it WAS a Jensen 50 so exceptionally rare in it's own right.  This one came packed in Sept. 1967 vintage newspapers from Jeannette, PA, that and it's features make it a good bet it was built about that time.  

My newly acquired Jensen 50 was complete with no irreversible damage and came with it's original corrogated box as well as a sturdy wooden outer shipping crate.  It also ran quite well upon firing it up, although it leaked profusely at the usual gaskets. 

Click here for more "on arrival" pics

On the negative side, much of the nickel finish was corroded, especially the face of the boiler.  Painted parts and wood I could refinish, but I felt the boiler and several other nickel plated parts needed to be professionally replated. 

So, after operating it a few times, I tore it completely apart and sent select parts off to a nickel replater for a 9 week turnaround.  It felt a bit like sending the Shroud of Turin out to the dry cleaners, but I was very pleased with their work upon it's return.

While waiting for replating to be finished, I got to wondering what it would take to restore and convert this engine into a working replica of a Jensen 51?   I was soon on a quest to build the 28th Jensen 51, (at least a decent replica of one). 

Replication was possible after several Jensen 51 owners graciously shared photos of their examples...I'm very thankful for their kindness.  Those photos gave me a rough guideline for how to move forward and for most of the fabrication they were my only guide...no plans, no measurements per se.   The project spanned 10 months almost to the day, from receipt of my Jensen 50 until I finished it up completely and steamed it on Dec. 19, 2006, a nice Christmas present indeed.  

Click here for "progressive restoration & construction pics"

To get a perspective of the size of the Jensen 51, here's the same picture as above, next to a Jensen #5.

All factory Jensen 51's bore a custom owner's logo on the water tank, often that of a power co. or university that used these pieces for display and teaching. 

I came up with a logo of my own that was reminiscent of a Jensen logo, but clearly indicating it was a replica by me.  Decals for the control box and a final "builder's plate" were made by the same process as the tank logo...Adobe Photoshop on a computer with printouts made to water slide decal paper.

To build my replica 51, I had to make a few compromises and parts substitutions along the way.

For example...Jensen themselves used an upturned Model 50 size brass boiler for their water tank, but those are not exactly to be found laying about.  Fortunately a stainless steel cookie "jar" was found that fit the bill nicely and holds just a bit more water than the real thing.  The combo AC/DC generator was also an impossible to find item.  The generator solution is described a bit further down.

The control box was the most difficult part of this entire project.  Doing the woodworking required learning how to operate a router to mimic the edge design of the box.  That was my first exercise in futility.  I eventually figured it out, and as a byproduct, I have lots of kindling to feed this year's fireplace!  Finding the same Shurite and Hobbs meters that graced other Jensen 51's, took months to track down from multiple sources.

BUT, the biggest challenge of all was wiring the darn thing up (actually several times 'til I got it right).  There is the 110 Volt AC incoming power you don't want to mess up, and then the separate low voltage AC and DC circuits. 

The control box is now correct, safe and it works as intended, but what a brain teaser.   I now have greater respect for the creativity of Engineer Randy Calhoun, who in 1977 perfected the control box concept for Jensen and helped build every Jensen 51 made.

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Side Note:  A check with the  Jensen Online museum shows Randy's 1977 prototype for the entire Model 51 design.  His design was put into production with very few changes.   The astute observer looking at my replica would realize that the Jensen 50 boiler at it's core,  was made at least 10 years before Randy's prototype was even built.  Hence my replica doesn't have the belled out style boiler face of Randy's prototype and all factory Jensen 51's since.  My boiler is the older flat faced type with built in stay rod running end to end.  None the less...it works and I can live with a bit of revisionist history !!

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Although the wood base on my original Jensen 50 was in good shape, I opted to go with 100% new wood and preserve the original Jensen 50 base, with it's cord, 3 plug receptacle and name tag intact.  I have since sold these parts to another Jensen 50 collector along with the original Jensen 50 box and shipping crate.  I wasn't very likely to ever reverse my 50 > 51 conversion efforts, so for a change opted to NOT store such stuff for eternity.  

The functioning condensate exhaust stack added below began life as a brass/nickel plated drain tube found under most kitchen sinks...amazing what you can adapt to get the job done.  ACE Hardware was a prime source for such retrofitted stuff and I would often haul a chunk of the project into ACE to find this or that bit I needed.  I even got my paint for refinishing the engine mixed up by ACE !! 

Lamp posts were mounted on extensions made from large scale veterinary syringe needles used on cattle...cut off the sharp tip and the friction fit and height extension for a standard Jensen lamp post was perfect.   A MacGyver fix for sure.

A factory Jensen 51 has the DC motor mounted in a more hidden location close to the rear of the firebox atop a piece of metal tubing.  I wanted the DC motor in a more visible location, yet I was somewhat limited for real estate.  I chose to mount the DC motor up on a little wooden pedestal of it's own as seen lower right.

The DC motor (courtesy of Odilon Marcenaro), was extracted from it's plastic Meccano housing and then epoxied inside a tube of aluminum, cut from the body of a permanent marker pen...the motor with it's aluminum "jacket" was then epoxied inside a nice brass mount I found on eBay. 

Since I didn't have a spare Jensen style silver saw blade to mount to the motor, I used a Jensen lineshaft pulley instead painted red to match the flywheel and generators.
 
You simply can't find a combo AC/DC generator of the type used on Jensen 51's and the equally rare Jensen 15D accessory set, as they were custom made by Jensen as each 51 or 15D was assembled. 

I opted instead to pair up two cast iron based Jensen model 15 AC generators.  I tied them together in the same "in line" configuration used on the first 3 Jensen production 51's before the combo generator came into being.

To supply DC power, a small, modern "stepper" motor was used, working in reverse to generate DC power.  Given the "stepper" motor was square and too modern looking for this project, I discretely concealed it beneath the paired AC generators in a hollowed out well.  It's pulley is tethered to the triple pulley above it.

To improve traction between the main flywheel and the triple pulley driving the heavy 3 generator load, I ran a double set of spring belts to either side of the "down" belt.  This setup works very well and was inspired by a two belt configuration seen on the pic of a Corliss engine that headlines this website.  Closeup of the triple pulley shows this arrangement more clearly.

The triple pulley setup was created by bonding three separate Jensen pulleys together with silicone sealant on their faces.  That stuff really bonds two flat surfaces with exceptional strength.

The pulleys allow for a set screw to make good contact on each generator axle, forcing them to perform as one.  The armatures are oriented in phase and wired in parallel, enabling them to support more lamps than the original solo AC/DC generator on a Jensen 51 could handle.  If you have to substitute, you might as well make an improvement at the same time !

Yes, the valve at the base of the feedwater downtube from it's tank above has a striking resemblance to the water supply valve found behind your family commode! 

I also drew some odd stares at the ACE store while test fitting that valve onto the end of an aluminum clothes pole, part of which became the feedwater downtube you see here. 

The valve on the downtube also provides incremental adjustment for the volume of water moved into the boiler by the engine driven feedwater pump.  That pump at first was quite puzzling to me and I struggled to understand HOW it worked and then to get it working properly.  With help from several Jensen 50/51 owners, we figured out it's eccentricities and now it works perfectly.  In a word, if you want it to pump, you have to keep your balls clean! 

Click here for how to's on getting the feedpump working as intended.

In the pic to the right you can see several other modifications made to the rear of the control box.  Those include adding a rotary dimmer switch for more gradual control of one  660 W heater, and a tiny switchable computer fan that keeps any heat buildup from occuring. 

The two white switches control the extra lamp posts, a master switch controls all line voltage and lastly the fuse holder protects against overload.  All line wiring, switches and fuse were upgraded to handle the higher electrical demands of the newer heaters given original  setup consumed 900 watts and this one over 1600 watts at full power.

The tank needed to sit on a platform of sorts attached to the top of the tower frame.  I spotted a plasterer's aluminum plate at a local store and with a little downsizing it fit the bill perfectly. 

The water tank has just one hole bored in it's base for the feedwater downtube, and it is otherwise attached to the plate with contact cement, as I didn't want to add more holes and potential leak points than needed.  The plate base and tank are now as one.

The tower frame was built from aluminum "L" angle picked up at Lowes Home Improvement store.  While trying to screw it all together it was like building a tower of Jello, but once assembled it took on amazing strength in all those angles.

This replica effort attempted to stay true to the basic design and looks of the original, but had to accomodate parts differences over the years and some minor improvements I wanted to implement.   Like the generator issue, I had to work with different immersion heaters.  300 watt immersion rod heaters are no longer made today, replaced with 660 watt versions.  I kept one good condition 300 watt rod and added two NEW 660 watt rods plus the ability to dim down one 660 watt rod via the rotary dimmer.

When all is said and done, this replica will heat water to a boil faster and maintain pressure under load more easily than a factory Jensen 51, primarily because of the higher wattage heaters used.  I bring things to a boil with about 12.5 amps on the incoming line meter, then dial that back to about 9 amps to maintain an optimum boiler pressure of about 25 PSI which will handle any load I place on it.

With greater AC and DC generating ability, I was also able to add 3X the lighting and a larger DC motor all of which can be operated simultaneously, although the power consumption and drop in engine RPM's is obvious, but that's the beauty of this piece.  With switches and metering galore, you can see first hand how changes in electrical load on a "power station" really effect things.  I can understand better what is happening when an electrical "brown out" occurs during periods of high energy consumption in our homes.  I also understand why many of the customers who bought Jensen 51's over the years were power utility companies and physics depts. of major universities, it's that great a teaching aid. 

As of July 2008, I have put 73 cummulative hours on the meter running/adjusting and simply admiring this replica.  The 51R (as I have come to call it) can go through a gallon of water in 90 minutes.  I found it necessary to install an exhaust fan over my workbench vs. turn the Temple of Steam into a rainforest!!!    It's a lot of fun to work the switches and tweek the other controls.  I have no regrets having spent the time and funds to create this replica...it is the most enjoyable piece of steam hardware I have and one I can start up and let run in the background for hours, topping the water tower off from time to time and checking the meters, water level, dab of oil etc....all stuff we model steamers love to do.

My sincere hope is that one day Jensen Mfg. Co. will restart the manufacture of their flagship Model's 50 and 51.  My guess is there is a pent up collector demand that would take all they could make for years to come.

Videos

I've filmed a couple of videos that follow.  While this setup will light 3 lamps and power a DC motor independently or together, I switched things on and off a bit so you could see the lamps more easily, as otherwise their glow was drowned out by the bright lighting needed to film.

Click below to see the first of TWO instant videos via YouTube:



Click below to see the second of TWO instant videos via YouTube:



Click here for factory vs. replica Jensen 51 Comparison Specs and Parts Sourcing