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4" Burrell DCC Showmans Cylinder Block

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4" Burrell DCC Showmans Cylinder Block Empty 4" Burrell DCC Showmans Cylinder Block

Post  Heavyhaul Sat 18 Sep 2021, 7:57 pm

Good evening all,
After some advice regarding one of our club members STW DCC Showmans engine he has been building for the past four years. As this is his first involvement with building steam engines he is at the point where he thought he was ready to steam the engine for the first time.
I suggested to our member that I would go over and fit my equipment so as to be able to carry out a hydraulic test, on the engine and to rectify any minor leaks before putting a fire in the firebox for the first time and then finding leaks.

After filling the boiler with water and then connecting the test pump, as I began pumping up the pressure we noticed several minor leaks which were then rectified. But as we began pumping again water appeared to be escaping into the valve chests and water coming out of the exhaust and into the smokebox.

We checked the regulator plate and regulator puck to make sure that they were fitting correctly, we removed a couple of burs and found that there was a small radius on the underside of the stainless steel plate, and when the three countersunk screws were loosened and removed found that the plate was not sitting down correctly, so after using a counter sink on the hole of the machined face in the block, refitted the plate which now was seating correctly and the regulator assembly.

We then replaced the plate and began pumping again, once again as the water reached the top and began pumping pressure, water was still draining into the valve chests and out via the exhaust and into the smokebox.

I have one of the original showmans which I purchased from another of our club members with the original design of cylinder block, and my other Showmans which is nearing completion has the modified cylinder block with the rear cover plate which when fitted says to use a suitable car filler to blend in so as to make it look like a solid casting.

Now my question to all the builders of recent Road locos and Showmans, are the cylinder blocks still supplied with the modified back cover, or has STW started sending out the original style of cylinder castings. Our colleague has the build instructions for the modified cylinder but has an original cylinder block, which during the first batch of Showmans and Road Locos they had a load of faulty cylinder blocks with pourus castings causing the cylinder blocks to be faulty hence why the new design to make the casting and the machining of the cylinder blocks to be easier.

Are the current cylinder blocks still sent out where the customer has to fit the rear cover plate as per the instructions or are they sent out already finished and made to look like a solid casting ?.

We also had our club boiler inspector helping today as well and we both came up with the conclusion that the cylinder block has a fault somewhere in one of the ports allowing the water to leak into the valve chests (High and Low pressure) and out via the engines exhaust.

Regards
Steve Honey (Heavyhaul)

Heavyhaul

Number of posts : 79
Age : 55
Location : Aylesbury, Buckinghamshire
Registration date : 2013-07-01

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Post  elwood-59 Sat 18 Sep 2021, 8:58 pm

Hi Steve,

all I can say is that Pied Piper has the modified cylinder. I picked it up end of 2017. Best get into contact with Will that, he will know.

Cheers

Elwood
elwood-59
elwood-59

Number of posts : 246
Location : Germany-NRW
Registration date : 2014-12-17

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4" Burrell DCC Showmans Cylinder Block Empty Re: 4" Burrell DCC Showmans Cylinder Block

Post  Heavyhaul Sat 18 Sep 2021, 9:09 pm

Many thanks Elwood, for your reply yes Chris who's engine it is, is going to speak to Will or Dean on Monday to see if they have any record of the type of cylinder block they supplied him. Chris said today that he can't remember fitting the modified rear cover.
I must admit from having a good look myself, it does look like one of the original cylinder block castings which they had trouble with hence the modified version.

Regards
Steve Honey (Heavyhaul)

Heavyhaul

Number of posts : 79
Age : 55
Location : Aylesbury, Buckinghamshire
Registration date : 2013-07-01

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Post  Steve Traill Sun 26 Sep 2021, 11:02 pm

The two main faults the original blocks had were in the passageways under the cylinders. When testing on air one fault was that pressure leaked from the vertical steam chamber going to the regulator straight into the low pressure exhaust which sounds like what you have. The other fault was pressure from the vertical steam chamber going to the regulator going into the inlet of the low pressure cylinder so that any pressure gets the engine running with the regulator closed. Opening the regulator stops the engine as it equalises the pressure.

To be fair it is a very complicated casting especially having blind bores. Redesigning the cylinder block with open bores made the castings much more reliable and they work just as well. The cosmetic difference in appearance especially after they have a few miles under their belt is minimal.
Steve Traill
Steve Traill

Number of posts : 793
Age : 64
Location : Illogan Redruth Cornwall
Registration date : 2008-06-29

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