Author Topic: Stevens Model Dockyard Engine  (Read 5683 times)

Online Chipmaster

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Stevens Model Dockyard Engine
« on: May 17, 2022, 09:51:56 PM »
This afternoon I was given this old vertical model steam engine to restore, could the members identify it please?

CRHC1727 (2) by Andy, on Flickr

All the engine castings are brass or bronze.
The base is cast iron.
The bore is 1.978"
Stroke = 3"
Flywheel = 8.5" diameter
Overall height = 19"
The cheese head screws holding the cylinder cover are 5/32" x 32 tpi  Whitworth form = the Meccano thread.

IWQF3603 by Andy, on Flickr

IMG_4506 by Andy, on Flickr

IMG_4507 by Andy, on Flickr

IMG_4505 by Andy, on Flickr

IMG_4497 by Andy, on Flickr

IMG_4500 by Andy, on Flickr

And it's got a bad knock as can be heard in this video from my Flickr Album

IMG_4503 by Andy, on Flickr

Andy
« Last Edit: July 28, 2022, 11:50:23 AM by Chipmaster »

Offline Jasonb

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Re: Can this engine be identified?
« Reply #1 on: May 18, 2022, 07:16:49 AM »
Not one I could name but the two bands on the cylinder are similar to what Stevens's Model Dockyard tended to favour as are the tee section frames and they tended to cast in non ferrous.

It does not look like it is all from one set of castings as the bottoms of the standards don't really fit the base as they overlap and also at the top they look to have been pushed outwards to make them "fit" the base but the flanges overhang the cylinder and the crosshead looks too wide

Pump is an after thought as it that Vee pully stuck right at the end of the crankshaft. bearing pedestals also look crude compared when compared with the top half of the engine so may well also indicate it has been grafted onto that bed casting at some time.

Online Chipmaster

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Re: Can this engine be identified?
« Reply #2 on: May 18, 2022, 08:34:29 AM »
Thanks Jason, yes I reckon it’s a Bitza for the reasons you pointed out. I haven’t found evidence of Stevens cylinders as big as this one so far.
The pump casting  looks like a Stuart Turner boiler feed pump.
I can work on  this engine in between coats of paint drying on my Stuart Major.

Andy




Offline Jasonb

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Re: Can this engine be identified?
« Reply #3 on: May 18, 2022, 12:14:05 PM »
I've got a reprint of their 1919 catalogue and the cylinders with the two bands were available in 1 3/4" and 2" bores though aimed at horizontal engines. The Tee section frames intended for marine engines went 1 1/2" and 2"but used plainer cylinder castings. So possible it was made up with a mix of castings.

Offline Alyn Foundry

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Re: Can this engine be identified?
« Reply #4 on: May 18, 2022, 12:38:28 PM »
Hi Andy.
The flywheel looks familiar to me. Minus the counterbalance.

This Brass flywheel was recovered from the Uppingham school workshop and has been “ doctored “ for use as a pattern.
The date Jason has provided fits in with the era of the school’s activities.

 :cheers: Graham.

Online Chipmaster

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Re: Can this engine be identified?
« Reply #5 on: May 18, 2022, 09:16:48 PM »
Thanks Jason and Graham.

After a little more cleaning the counterbalance on my flywheel can be seen to be a piece of lead wedged in between the spokes and blended in with the outer face of the flywheel.

  IMG_4533 by Andy, on Flickr

IMG_4535 by Andy, on Flickr

Andy

Offline Jasonb

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Re: Can this engine be identified?
« Reply #6 on: May 19, 2022, 07:50:08 AM »
Funny enough I recently did similar to a Stuart 7" flywheel though I just bonded on some strips of lead with JB Weld.

What condition is the boiler in, ort is that just a water hopper feeding the pump that I can see?

Online Chipmaster

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Re: Can this engine be identified?
« Reply #7 on: May 19, 2022, 10:44:31 AM »
Morning Jason,

The boiler;

Welded steel construction, possibly ex gas cylinder going by the weight, horizontal water tubes, probably gas fired.

 NIIZ4751 by Andy, on Flickr

IMG_4512 by Andy, on Flickr

Condition;

The water level gauge is intact
IMG_4512 (2) by Andy, on Flickr

Foundation Ring....
IMG_4520 by Andy, on Flickr

Genuine A J Reeves & Co pressure gauge in need of repair
IMG_4517 by Andy, on Flickr

I don't intend to try it out.

Andy

Online Chipmaster

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Re: Can this engine be identified?
« Reply #8 on: July 28, 2022, 11:49:14 AM »
A couple of months later the consensus is that most of the engine is Stevens Model Dockyard and it needs a lot of work to sort it out. It knocks very loudly, the crankshaft is bent and the bearings are worn but it does run, I'll have a go but completing my Stuart Major has priority.

The crankshaft wasn't properly supported, one of the main bearings was in the wrong position because the void in the old cast iron base meant it couldn't be fixed in the correct position.

IMG_4561 (2) by Andy, on Flickr

I used a 1/4" thick brass plate to cover the old base and make a fresh start.

IMG_4672 by Andy, on Flickr

IMG_4739 by Andy, on Flickr

This enabled the main bearing to be moved between the crank web and eccentric.

IMG_4744 by Andy, on Flickr

The brass plate will improve the appearance.

IMG_4748 by Andy, on Flickr

However, it seems I will have to replace several parts to sort out the knocking, perhaps another crankshaft if I can't straighten the original. Here's a recent video of the engine running on compressed air. The first part of the video shows the engine at the outset then running after the brass baseplate was fitted. The knocking is terrible, I suspect the piston hits the lower cylinder cover but because of the way the engine was made there is no means to adjust for that.

 <a href="https://www.youtube.com/watch?v=N4k9T31Tw1k" target="_blank">http://www.youtube.com/watch?v=N4k9T31Tw1k</a>

Andy




Offline internal_fire

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Re: Can this engine be identified?
« Reply #9 on: July 28, 2022, 03:09:24 PM »
I suspect the piston hits the lower cylinder cover but because of the way the engine was made there is no means to adjust for that.

Depending on the situation at the top end it might be possible to lower the standard a tad. Shaving the bottom of the feet could be difficult, but since you have added the brass base it should be quite easy to make a small recess under each foot.

Alternatively, the crankshaft could be shimmed upward.

Gene

Online Chipmaster

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Re: Stevens Model Dockyard Engine
« Reply #10 on: July 28, 2022, 04:58:38 PM »
Thanks Gene, I'll try shims under the main bearings.  :ThumbsUp:

Andy

Offline Michael S.

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Re: Stevens Model Dockyard Engine
« Reply #11 on: July 28, 2022, 08:04:11 PM »
Oh, I should have turned up the volume of the video before commenting on Youtube 😏.
Now I hear the knocking too.
What irritates me, however, is that the concentricity of the crankshaft is even. I mean there is a small stop, which I would assume when the piston hits the cylinder. The crankshaft should run jerkily.
If it's the piston, can you trim it from the bottom?

Michael
« Last Edit: July 28, 2022, 08:08:10 PM by Michael S. »

Offline crueby

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Re: Stevens Model Dockyard Engine
« Reply #12 on: July 28, 2022, 08:15:38 PM »
That kind of sound could also be slack in the bearing at either (or both) ends of the con-rod, or movement in the main bearing (less likely). If you turn it over by hand with no air pressure applied, you should be able to tell. With the crank horizontal, turn slowly one way, stop, and go back the other way. If there is a loose bearing, you'll feel/see that the piston doesn't move for a short part of the rotation back and forth. If it is hitting the cylinder end, you should be able to feel that too as the piston stops and the conrod/crank have to pull through the last of the turn at the bottom or top. If its hitting, can't be by much since it can make it around the turn.


Offline Jasonb

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Re: Stevens Model Dockyard Engine
« Reply #13 on: July 29, 2022, 09:01:52 AM »
Even a very worn big end bearing would allow the piston to come down a little further than it should. best to track down exactly where the problem is (problems are) before machining bits of metal off that you can't put back on.

Online Chipmaster

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Re: Stevens Model Dockyard Engine
« Reply #14 on: July 30, 2022, 07:55:02 PM »
When I took the cylinder apart there was a lot of crud between the bottom cover and the underside of the piston but probably not enough to cause the knocking but it did seem worse at bottom dead centre.
This picture shows there is approximately 1/8" clearance at bottom dead centre.

IMG_4849 (2) by Andy, on Flickr

So I had a closer look at the crosshead, there was some slack in the bearing. After cleaning I could see that the crosshead had been sleeved.

IMG_4853 (2) by Andy, on Flickr

IMG_4854 (2) by Andy, on Flickr

The bodged soft brass sleeve was drilled out, it had been a forced fit. 5/16" o.d. and 1/4" i.d.

IMG_4857 by Andy, on Flickr

That should be easy to replace.

Andy

 

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