A little something about Jensen: Click Here
Engines in this Collection:
(click hyperlink to jump to that engine type)
Approx. Dates: Model
late 1930's...................# 5 "Riveted Boiler" Oscillator
..#10 "Riveted Boiler" Power Plant w/horseshoe cast 1951...........................#10 Power Plant w/ round (1951 only) cast iron base
generator
mid-1940's.
..#20 "Big Power Plant" w/horseshoe cast iron generator
1937...........................#25 "Riveted Boiler"
(also called a 4 bolt #25 or Big Cylinder #25)
late 1930's..................#25 "Riveted Boiler" non-reversing type
early-1960's................#25 reversing type
May 2007....................#25 reversing type
(late 1950's engine modified to alcohol firing)
Nov. 2006...................#30 (parts replica) 1954 era engine
Nov. 2006...................#40 (parts replica) 1960 era engine
Dec. 2006...................#51 (replica) built up from 1960's era Jensen 50
1949-1950...................#55 Twin Cylinder with early style reverse
Dec. 2005...................#95G Turbine Power Plant w/ modern alum. generator
(hand signed #3 by Mr. Tom Jensen, Jr.)
Accessories in this Collection:
(click hyperlink to jump to that accessory)
1948-1950...............#100 Workshop w/ blue painted plywood base
1951-mid 1980's.....#100 Workshop w/ natural plywood base
1952-mid 1980's.......#15 Generator blue cast iron base/3 pc. magnet
A little about Jensen Engines and Accessories
There are a miriad of makers long since gone out of business, and a few still around, but there is just something about Jensen's "Abrams Tank" demeanor that draws me to them.
Jensen is still very much in business at their original Jeannette, PA, U.S.A. location, and although "old world" in their manufacturing processes, they have a state of the art Jensen website worth a leisurely visit to view their currently made models, tour their one of a kind shop, see how they make their engines and meet the handful of people who ARE Jensen today. Their museum section Jensen Online museum for models dating back to the early 1930's is the gold standard for Jensen identification, and much of my information ties back to it. If you need parts for new or old models, Jensen generally has them and they are just a phone call away.
For another perspective on Jensen the company...Click HERE for an interesting magazine article about them.
Click HERE for a jewel of a video done a few years ago for the Pennsylvania TV market, it takes you inside the factory to meet the people and see how and where Jensens are made.
As for my Jensen favorites:
You will see an overall preference for the following things in my Jensen collection:
They were used for added strength before the transition to silver soldering boilers together that made rivets unnecessary. 
This engine features a number of things that date it to about 1938 or 1939:
- longer boiler...earlier ones were shorter
- tall/longer smooth black firebox...earlier ones were shorter and squatter
- riveted boiler (10 per end) with soldered in bushings throughout
- riveted boiler straps vs. nuts and bolts
- early design external sight glass and steam dome, with solid vs. hollow steam screws
- straight black dowel handles...bit longer than later ones
- nickel plated cast iron flywheel
- cloth cord exits chimney base via a flared hole (before Heyco connectors) and chimney base has screwed on cup that supports the chimney
- robins egg blue cast iron engine base with cast in horseshoe shape beneath flywheel...later versions squared off the recess and were painted a darker blue

As with the other riveted, 1930's vintage Jensens in this collection, this engine has a black painted, brass chimney.
In the forties Jensen transitioned this to nickel plated brass, but the painted version is correct for this engine.
So, how well does it run??....Sweet, check out the video below.
Click below to see an instant video via YouTube:
To say I've been looking for one of these for "awhile", would be an understatement. This is now the earlier of two styles of Jensen 10 power plant I have in this collection.
This engine came to my collection in the same way as most, via eBay, but with a bit of a twist this time. As listed it was missing the standalone lamp post and the generator electrical contact setup seen here. As a result it did not meet the seller's reserve price and went unsold.
I then contacted the owner and negotiated a sale, taking a chance I could find or make suitable replacements for the missing parts. Upon receipt, I did hesitate for 6 months to refinish this like my other robins egg blue/riveted boiler pieces, wondering if I should retain it in it's original condition, engine rust and all.
In the end my OCD tendancy won out and I'm glad it did.
This engine has many of the exact same dating features noted on the late 1930's Jensen 5 that preceeds it above...even the wood looked like it was of the same grain! I would therefore estimate the date of this engine at 1938-39.
It would NOT have been earlier than 1938 as an example in the Jensen online museum dated 1937 used a more complicated electrical contact setup that appeared to be made of bakelite. Mr. Jensen simplified this a bit a year later to what you see here. I thank steam friend Gil for some photos to go by to replicate the masonite/brass contact block...it now mimics yours exactly and works perfectly.
This engine got a complete restoration as well as a new made stand alone lamp, new painted brass chimney patterned off the original, and a new generator contact block. I finished it up in July 2008 and I'm once again impressed with the design genius that went into this engine by Mr. Jensen.
It is truly an elegant piece yet among the most efficient he ever built.
The straight line generator configuration common to the early Jensen 10's, results in less waste energy than a separate generator connected by belt, hence the lamp glows very bright on this design.

The boiler's nickel finish and general condition is about the best of all my Jensens. Their earliest boilers and engines benefited from superior metal preparation (burnishing) and what seems to be multiple layers of plating.
This caliber of metal preparation could probably not be sustained during or after WWII without pricing Jensen out of the market. It is nice to find one however, nearly 70 years later!!
I discovered an oddity I've not seen before. The firebox on this piece was designed so the boiler strap retention screws threaded directly into the firebox lip itself. This is the first example I have come across like this...all others were either nut and bolt, or riveted. It was so simple to re-attach the boiler straps on this one, that it made me wonder why this strap attachment method was tried and abandoned?? Perhaps stripping out the holes became a problem?
I'm pleased that this particular engine did not get Mrs. Jensen's COMPLETE paint job...where she also painted the copper windings inside the generator as seen on many examples. The windings on this generator were left unpainted, for which I'm grateful!!
Like the Jensen 20 further down the website, I took an extra liberty in this restoration...I uncovered and polished the nickel plated screws on the generator's sides which are always painted over. I know this was not an original feature, but it should have been !

Like my other in-line Jensen 10 (1951), this one runs like a champ as can be seen in the following video. It was well worth taking a gamble on buying this engine, I could not be happier.
Click below to see an instant video via YouTube:
This Jensen was a must have for an odd sort of reason. You see, this engine and I were both made exclusively in the year 1951. Apparently the mold was broken in both cases, too hard to replicate !!
As for the Jensen, it was the one and only year Mr. Jensen machined the magnet for the Jensen 10 from a solid piece of iron (also referred to by some as the "Omega" style magnet). Before 1951 the generator magnet was made in a horseshoe shape as in the previous Jensen 10 example. After 1951 the generator magnet became a 3 part affair and is made that way to this day. 
Detail of the one piece round magnet can be clearly seen in the picture to the right. This whole setup runs beautifully and the light output is as strong as any generator I own.
Restored? Well, yes, partially. Although in very nice shape overall as received in a recent private sale, the paint was thin on the engine and the magnet itself.
This piece meant too much to me to NOT put it in first class shape. So the base was stripped, sanded, stained and polyurethaned and the paint was redone on the engine and magnet. I did opt to leave the firebox in original condition because it was nearly perfect. Nice bright screws, a bit of polish on the boiler and she's looking good.
This Jensen 10 looks like it was made yesterday, just the way I like them. Unfortunately my 57 years are definitely showing and no amount of paint or polyurethane seems to help !
In early May 2008 I experienced a "Perfect Wave" so to speak in the world of eBay auctions. My find was what Jensen originally called their #20 Big Power Plant". It featured a non-reversing 20 sized engine with 3 inch boiler, driving a tough to find standalone horseshoe magnet style generator all mounted on a solid wood base. The auction BIN price was right and in 20 seconds I was the winner.
I was the first to view that auction and friend Gil was #2...but by the time he hit the BIN button, it was sold. I've never pulled that off before and was further amazed when Gil called me moments later laughing out loud that he missed it by seconds.
The first picture below is how it looks now AFTER full restoration.

This BEFORE picture is how it looked on eBay.

As described in the auction it needed a chimney, chimney stand, heater and cord, but otherwise was in decent shape. Upon receipt I was delighted to find that although the heater was dead, it was in the company of the chimney stand, something I figured I was going to have to otherwise make by hand.
I gave this one the "full meal deal"...complete restoration from top to bottom.
I have made a number of Jensen decals, but this was my first UL sticker and I was pleased with how it turned out. It might seem a minor thing, but such stickers are like ID labels to me, the engine isn't complete without one.

The nickel polished up nicely and was set off with new high temp firebox paint and my standard blue tractor paint for the cast iron surfaces. I swear Jensen used such tractor paint originally...though mine is a few coats thicker than factory original!
The blanket heater was replaced with a new one from Jensen and the tired looking cord was also replaced with a new, period correct cloth covered type.
The
flywheel and engine are precision works of art on this piece. They
polished up nicely to look the part and perform flawlessly...early
Jensen nickel plating was amongst the best they have ever offered. 
Being a mid-'40's version of the #20, this engine was made before Jensen began adding the Stephenson's Reversing Linkage as seen on younger versions. It goes one direction and one direction only...but does so quite elegantly!
The
horseshoe style standalone generator is one of the earliest generator
versions Jensen produced and in my opinion, the strongest version
measured by light output.
The horseshoe variety just captures my heart for best of show vs. any other generator type out there including other Jensens. I was delighted to learn that these early horseshoe type generators also featured a machined brass pulley with nickel plating...all Jensen pulley's since are of the aluminum variety.
All things considered I feel very fortunate to have obtained this engine and been able to spruce it up for another 50 years of enjoyment by me and the owners that will follow me.
It runs beautifully as can be seen in the following video.
Click below to see an instant video via YouTube:



I must confess however that steam friend Kirby was kind enough to sell me a proper replacement boiler and the even rarer ceramic internal heater, even AFTER I beat him out by a few dollars to win what you see via eBay!
I think Kirby figured if one of us was to get it, he'd be sure there were enough parts to make it whole and operational again. Thank you again Kirby, I hope I did your kindness justice.
The "4-bolt" is definitely the most extensively restored engine in my whole collection, and although a completely overhauled piece, it's now worth 10X to me what it was when I got it. By "worth", I don't mean a market worth (which I'm not concerned with), it's a Rog worth and it's a function of hours invested and personal satisfaction with the finished result.
Restoration Process
To get from "Boat Anchor" to "Best of Show", the process sort of went as follows.
The original wood finish itself did not hold up well to years of water staining from most that I have seen, this one being a prime example. I am correctly accused of "over restoring" most of my engines, but I first want to ensure durability, since I do run these engines regularly. Secondly I want a nicer, smoother finish akin to a piece of furniture, something Mr. Jensen would have never bothered with, but he was making thousands of them and I have the luxury of time to lavish on a few. It works for me.
The black firebox was likewise stripped, sanded of rust and sprayed with several coats of a semi-gloss high temp automotive engine enamel. If you look carefully at this firebox vs. later ones with 2.5" diameter boilers...it becomes apparent that this model used a lower profile, shorter firebox with a shorter boiler.
Since the engine was missing it's chimney and the black base it sits on, I reworked a spare Jensen 35 chimney base to the proper dimensions. A correct black painted brass chimney finished off the firebox as originally designed. Jensen switched to nickel plated brass chimneys later in the forties, but for a late thirties engine this is correct.

I matched the original robins egg blue on the cast iron base and inner flywheel, by mixing three model railroading paint colors to as close a match to new as possible. Jensen lore has it that Mrs. Jensen used to hand paint these engines on the kitchen table with that curious robins egg blue paint, something Mr. Jensen got a deal on in during tight financial times. Funny, but I probably paid more for 2 ounces of modeling paint than he did for a 5 gallon pail of the original stuff !
The boiler and other nickel bits were polished using the time honored hand technique of "SimiChrome on - SimiChrome off"...over and over 'til they looked right without rubbing off too much nickel. I replaced the cloth cord with another that was "new old stock" of that period bearing the same black and white pattern and ensured the electrical connections were safe and solid.
I thought of trying to re-use the original cord, but despite repeated "washings", it still looked awful. It makes me wonder at times where some of these engines got stored for their 50-70 year nap! This one could have been a refugee from the floor of a dirt cellar it was so cruddy.
The Jensen decal was the final touch as the original was illegible upon receipt and thus stripped off with the finish. I made a re-creation of the original Jensen decal using a digital photo of a good one, further cleaned up using "Photoshop" computer software, then replicated onto new water slide decal paper. Making such a decal was tedious work, but worth it in my opinion.
The decal (shown to the right) looks almost too perfect, too new - hence it had to adorn
an engine that looked like the day it left the factory. I'm very pleased with the overall appearance and if Mr. and Mrs. Jensen Sr. were around today, I think they would approve, though they would probably admonish me for spending too much time on it!
Here is a soul mate to the 1937 Riveted Boiler 4-Bolt shown just before this one. 


At this close of a photo, you can tell from the grain of the wood that this (and the 4-Bolt) received a furniture smooth finish somewhat nicer than they came from the factory.
It was Jan 2003 and this was my first Jensen and only my second steam engine after my childhood Fleischmann.
I looked for several months on eBay for "something" that caught my eye, having never even heard of Jensen.
It turned out that this was the childhood engine of a gent living less than 30 miles from me. He indicated it was a Christmas present in the early 1960's. This timeframe is consistent with Jensen's change from copperclad brick imprinted steel to a pinker painted version in 1961. Also, no postal zip code on the aluminum ID tag would place it before 1964 when "zip" codes were introduced in the U.S. This also marks the third type of ID tag used by Jensen (decals in the earliest years, later brass tags and by this time aluminum).
The original owner regretfully sold it, but admitted he had pretty much buggered up the face of the boiler with bathtub caulk in a failed attempt as a kid to stem a leak. If he'd only known as a kid that the round boiler face sight glass retaining ring is easily tightened or loosened and replacement gaskets from Jensen always solve such leaks.
Upon receipt I was immediately taken with this engine.
The connecting rod was beautifully machined and reminded me of something off a locomotive. The whole thing just spoke of quality and care in construction, this was a notch up over my Fleischmann!
While the "pink" faux brick firebox color seen on more modern Jensens has few collector fans, this engine's firebox used a copper clad steel in such a way that the whole firebox looked like a bright and shiny penny.
This copper clad version dates the engine to the very early 1960's and was used by Jensen for a very short time after smooth black fireboxes ended and before changing to the pink brick version used up til present.
My personal favorite firebox is the semi-gloss black/smooth metal type, but I quite like this presentation as well. If you study the engine on this one a bit, you'll see it has a proper Stevenson's reversing linkage built in, an uncommon feature in a toy steam engine. You just flip the little red lever, and this engine will reverse on the fly, 9 out of 10 times without needing a hand spin on the flywheel to restart.
This engine represented my first attempt at restoration of a toy steam engine. I did a few dumb things like use nice shiny new screws that were too long and they popped thru the bottom of the board...oops, but otherwise it turned out pretty well for a first effort. I had to refinish the base which had suffered water damage and some delamination of the plywood from the leaky sight glass.
I repainted the engine it's original dark blue shade having found a perfect match in spray paint used for farm equipment. The color is simply called: "International Blue", with International being a brand of tractor popular in the U.S. It would not surprise me if Mr. Jensen simply bought quantities of tractor paint figuring if it's durable enough for farm use, it would probably hold up just fine for his engines.
I gingerly removed about 1/4" of caulk from the boiler face and found the original owner had pretty much chewed up the sight glass retaining ring with a screw driver and hammer before adding the caulk!! I replaced the sight glass retaining ring with a new one from Jensen along with proper new round gaskets and it runs great. I also have an early riveted Jensen Model #25, but I prefer to run this one given it has the reversing mechanism and the other does not.
Click below to see an instant video via YouTube:

It
used a
typical meths burner you might find on a British Bowman engine and
looked as you see in these file photos. 





This brings me to the Jensen #30 you see here. This is NOT an original piece...at least it didn't originate from the Jensen factory as the assembly you see here.
I'm not certain of the exact stain color used by Jensen on wood based models of the '50's and '60's as there seems to be a lot of variation out there which was applied on various types of wood and has worn to varying degrees. 

The
cast iron #5 engine I'm using has the heavy type flywheel, squared off
crank and flat ended cylinder typical of #5's from the
1940's-1950's.
Perhaps this is the Jensen answer to the Empire B-42.
Both are twin cylinder, but Empire approached the increased steam volume needs with two boilers to power two flywheels and two cylinders.
Jensen used their 3" boiler with it's larger blanket style heater to power 2 cylinders and one flywheel.
Frankly Jensen came up with a simpler design and better performing engine in my opinion, though I think the Empire might have it beat in the visual "wow factor" dept.
This engine was purchased from the collection of a former Jensen sales manager. Plywood base, flat boiler face, external sight glass, red handles, brass #20 tag overstamped with a #55 and the older style reversing mechanism, place it in the 1949-1950 range as best I can tell. 1949 seemed to be a pivotal year during which Jensen changed from cloth to rubber cords, solid to plywood bases and black to red handles.
The reversing mechanism changed in 1951 to the type common today, hence this #55 had to fall in the first 4 years of production of this model which started in 1947 and the cord, base and handles would tend to indicate the 1949-1950 timeframe .

The engine ran "OK" when I got it, but never seemed to have the power I expected compared to another Jensen 55 I had owned, so it didn't get run as often as others. Twin Jensen's can be a pain to "time" as you must get each cycle of piston in sync with the other not working against each other. Despite re-timing it, I still felt it was a poor doer in the RPM and umph dept.
One day in late 2005 I tried to run it only to find the heater had shorted out and died...no steam that day. I proceeded to order a 3" heater replacement direct from Jensen and upon installation I discovered two things. First, the engine had been previously restored given tell tale traces of black paint on the underside of the boiler from the firebox being painted with the boiler in place. That was really no surprise as many of these engines got "spruced up" over the years.
The second, bigger surprise was that the heater installed was the wrong one. It had a heater meant for a 2.5" boiler, which is about 3/4 as large as the proper one for a 3" boiler. I had new and old examples of both to compare it to and sure enough, that engine had the wrong heater. Most likely this was the reason for it's lackluster performance. Whether the undersized heater was installed accidentally at the factory years ago, or someone swapped the wrong one as a replacement, I'll never know. Boiler strap rivets looked original, so a factory error is possible, but rivets can be replaced, I do it !!
So, since I had to tear it down for heater replacement, I went ahead and gave it the "full meal deal" for restoration, re-doing the base wood finish, firebox and engine paint, then painstakingly replacing the boiler strap rivets I had drilled out.
It's now an eager runner, about 2X the speed and power as when it had the undersized heater. The new and larger heater made a world of difference, it's now the work horse it should be and a looker on the shelf or under steam. I guess I should be thankful the heater burned out, otherwise I would probably have just grumbled about this engine being a poor doer, for years to come. I'm also thankful that heater replacements like this are still available from Jensen for engines more than 50 years old...another Jensen fact that endears me to them.
Click below to see an instant video via YouTube:
What do you get when two of your favorite toy steam makers join up and turn out a combination piece?
You get the Jensen 95G Turbine Power Plant. 
This
model, introduced in December 2005 is the culmination of several years
of planning, and represents the best of Jensen teamed up with a young,
innovative turbine maker by the name of Karsten Gintschel of Cottbus,
Germany.
Steve
and Karsten hit on a brass geared transmission of sorts connecting the
turbine to a Jensen flywheel which in turn was connected to the
generator by spring belt in the conventional way. Eureka, it got
the job done of powering the Jensen Model 15 generator quite nicely
with capacity to spare. This Power Plant setup is the coolest
sounding engine I've ever heard, very reminiscent of a jet engine
spooling up. If
you take it outside in the cold of winter (which of course I did), you
get enveloped in a cloud of steam spewing from the turbine.
Strange looks from the neighbors come free of charge ! The video
at the end of this page is a must to see and hear.
My specific example is #3 out of the initial 25 made. These initial pieces were built, signed and dated under the base, by Tom Jensen, Jr., owner of the company (see pic below).
By
the way, the aluminum based Model 15 is the successor generator that
replaced the cast iron based version. While a bit of the charm of
the old cast iron model is gone, this generator more than equals it in
electrical output.
Jensen also sells the Model 15 as a stand
alone accessory, but it's part of the package on the 95G.




