Awesome Mike!! This is the way Jensen should have built them, the cylinders look more correct than the small ones normally used
That sure is a cool engine Mike, congrats!
Awesome Mike!! This is the way Jensen should have built them, the cylinders look more correct than the small ones normally used
I agree! The engine looks so much more robust!
Very cool and very interesting. Congrats, Mike..!!!
I built a 55 with 4 screw cylinders and I believe they are bigger than what are on your newer engine.
I also think this one has smaller screws than what Jensen uses on their 4 screw cylinders.
When you receive it, please measure the outside diameter and compare to your pre-war #25 cylinders and let us know.
Whatever the origin, the modification work looks excellent!
Thanks, Gil!
I can’t wait to examine it when it arrives on Monday. 😁
One thing I find interesting is the early style block-off plates used on the valve chests. If someone modified the normal cylinders that would be found on an engine like this, I would think the valve chests would have the rivets plugging the holes like you’d usually find.
.
The extra large exhaust pipes and the early style port covers (on the steam chests) are features found on mine due to the early cylinders I used. I have only seen the large exhaust ports on the smaller military air pumps Tom Sr. made for the DOD.
Gil,
These cylinders measure 1” OD just like all my pre-war cylinders. The engine base casting does have the corners ground off where the cylinders mount. There is also a washer behind each crank to accommodate the wider spacing of the cylinder centers due to their size. The plywood base is actually beveled like most are and it’s larger than a normal 55 base. The original box is marked for a model 20 engine. I believe this engine was built this way by Tom Jensen Sr as an experiment or just to use old cylinders that were laying around. He may have made a bunch of these cylinders that the DOD never needed and just wanted to use them up. Your guess is as good as mine, but I really can’t see some hobbyist just having these cylinders and doing this modification in their home shop on their own.
Hi Mike, Re a Tom Sr. build... after reading this post I believe you are correct. He did what I would consider a better or more proper job than I did. Looks like he may have had to shorten everything that fits between the cylinders (pipes, reversing axle, etc) That is a superb piece of Jensen history!
I would sure liked to have had access to a surplus supply of 4 screw cylinders. Word is that at some point, possibly 30 years ago, someone was given a pile of unplated 4 screw cylinders that he was going to use for something but the fellow cashed them in for scrap without asking Jensen if they would like them back.
Very cool and very interesting. Congrats, Mike..!!!
I built a 55 with 4 screw cylinders and I believe they are bigger than what are on your newer engine.
I also think this one has smaller screws than what Jensen uses on their 4 screw cylinders.
When you receive it, please measure the outside diameter and compare to your pre-war #25 cylinders and let us know.
Whatever the origin, the modification work looks excellent!
Thanks, Gil!
I can’t wait to examine it when it arrives on Monday. 😁
One thing I find interesting is the early style block-off plates used on the valve chests. If someone modified the normal cylinders that would be found on an engine like this, I would think the valve chests would have the rivets plugging the holes like you’d usually find.
.
The extra large exhaust pipes and the early style port covers (on the steam chests) are features found on mine due to the early cylinders I used. I have only seen the large exhaust ports on the smaller military air pumps Tom Sr. made for the DOD.
Gil,
These cylinders measure 1” OD just like all my pre-war cylinders. The engine base casting does have the corners ground off where the cylinders mount. There is also a washer behind each crank to accommodate the wider spacing of the cylinder centers due to their size. The plywood base is actually beveled like most are and it’s larger than a normal 55 base. The original box is marked for a model 20 engine. I believe this engine was built this way by Tom Jensen Sr as an experiment or just to use old cylinders that were laying around. He may have made a bunch of these cylinders that the DOD never needed and just wanted to use them up. Your guess is as good as mine, but I really can’t see some hobbyist just having these cylinders and doing this modification in their home shop on their own.
Hi Mike, Re a Tom Sr. build... after reading this post I believe you are correct. He did what I would consider a better or more proper job than I did. Looks like he may have had to shorten everything that fits between the cylinders (pipes, reversing axle, etc) That is a superb piece of Jensen history!
I would sure liked to have had access to a surplus supply of 4 screw cylinders. Word is that at some point, possibly 30 years ago, someone was given a pile of unplated 4 screw cylinders that he was going to use for something but the fellow cashed them in for scrap without asking Jensen if they would like them back.
He didn’t have to shorten anything between the cylinders. If you look at a normal 55, there is actually a gap between the cylinders and the steam pipe blocks that sit on the valve chests. On this large cylinder engine there is no gap and it all measures the same. He did have to shorten the vertical section of the steam pipe though, because the valve chests on the large cylinders are thicker than the ones you’d normally find on a model 55.
That is a very sad story about the unplated four screw cylinders, but it was just junk brass to him at that time, unfortunately.