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Discussion Starter · #1 ·
Recently we received an Aster Berkshire that was a bit "under powered." Despite making steam it did not have much for power, speed, or for that matter,

To find the problem(s) it was necessary to break in down to the base units: wicks, fuel flow, exhaust, water pump, cylinders, etc.
A major problem was found with the cylinders, with gasket that were deteriorated and the compression o-rings on the steam tee fittings badly deteriorated, causing severe steam and oil leakage. Made quite the mess under the smokebox, oil everywhere. The passages were also badly clogged with sealant, a reduction from 1/8" ports to >1/32" this meant that there was a full cylinder rebuild in store. The oil was very acidic in nature, possibly due to too much tallow and ate through teh silicon and fluoride o rings in the fittings and glands



The pictures tell the story:
Poor condition of gasket and clogged passage ways that was a major cause of the poor power delivery:

Outline of the crossporting....YOU SHOULD NOT SEE THIS! This is due to overzealous use of sealant and is restricting steam flow to the cylinders. If your kit looks like this when looking down into the ports, disassemble the cylinders and correct it.


http://www.mylargescale.com/1stclass/Charles/TR3 services/Berkcylindexportrgasket.JPG





Cylinder ports are clogged:


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Here is the plug pulled out of the ports



Combine with the bad "O" rings that allowed loss of steam at the tee fittings :

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"O" ring comparisons (Bad on left and right, new OEM replacement in center):


New "O" ring

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The cylinder faces were then wet-lapped with 600 and 1000 grit sandpaper. All of the gasket mating surfaces are lapped as well to rid them of any old gasket material or scratches from the removal of old gaskets, some see it as over kill, but it is good practice, ensures a tight seal without a gasket (static friction), and makes the surface level and easier to assemble. All threaded holes were cleared with a tap to be safe.

New gaskets were applied using a thin film of non-rtv sealant (OEM Aster works very well for this, no acetic acid or other heat reactive chemicals to worry about) impregnated into them. The easiest way to do this is to use a dab on your thumb and forefinger and pat the sealant into the gasket, working your way around until the gasket is saturated. carefully lay the gasket on the part and assemble. No excess mess, just wipe the little bit of overlap from the outside of the part and you are done.


Photos of the gasket impregnating technique:




Here is the gasket laid atop the crossport plate:




Wiping the overlap from the outside faces:






On to the track for a steam test:

Drain cocks




Running well on the straight:



About two days worth of work and the engine is as good as new. Tomorrow is the shakedown run with a long haul freight.


Back to the shop for the next locomotive, an Accucraft GS4 (demonstrator model) then onto the test track again!
 

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Geez.
I saw the title, thought BL had turned the old Triumph TR-3 production line into restoring BR steam locos.
 

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Discussion Starter · #7 ·
Reminds me of Inspector Morse....


For us similiar to the GS4 v.5 with a smph of 200 we strive for performance for the money ( Power train 2006 Subaru WRX STI 4.2sec 0-60 and 12.6 sec 1/4 mile and rally speed of 156 mph rev limiter on stock setup) but really enjoy the classic looks of vintage auto (maybe one day...)


Second track test of prototype Accucraft GS4 (first test of upgrades at Dan's very cold steam up last weekend, today mid-40's) was thumbs up. Tomorrow at PLS for both the Berk and GS4 for the annual Turkey Trot run closing out the season!







Gordon should remember this engine.....
 

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Not to get too far off-topic (yeah, right).
I think somewhere I still have an early 50's Road and Track or Car and Driver or some such where they showed how to take the column shift off a 1940-1950 Ford, modify it into a floor shift, mount it in your daily hot-rod so the lever was on the left.
That way you would be used to shifting your RHD Limey Limo at the sports car races on the weekend.

Oval grilles on a Jag.
The only other one I'd want had a narrower 7-bar grille and two doors.
 

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Discussion Starter · #12 ·
Gordon
Making great steam....retrofitted the side rods with ball bearings, new piston rings, O rings, burners have your "flying V" spacer, quick disconnects, new tender pump, safeties rebuilt, suspension adjusted and re-timed. Looking forward to the run today. Off we go then, post later.


Alan
Thanks for the called and message, talk to you when we get back from PLS.
 

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Dear Charles

Thanks for posting the photos. They allways say more than words. Your job looks very proffesional.
I have a problem with a leaking gasket, but have had trouble finding a material that is thin and elastic.
I have thought of using safty rubbergloves made of VITRON. They are thin and the marteial is elastic and cemical + heat resistant.
You are using a traditional material. Can you come up with some product names? That would help a lot.

Best Regards

David
 

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David,

The gaskets used were OEM aster, but really any suitable fibre paper will suffice for a seal. Try getting Kraft paper from the local supermarket, which is recycled cardboard presses very thin. A lot of people use this as a wrapping for packages (comes in a large brown roll) or even to soak up the oil from cooked food. A brown paper bag does the job nicely.

I have also used graphite impregnated sheet, harder to find, but no leaking. The OEM aster gaskets are made of aramid paper, which has woven ceramic fibre. Over here our paper one dollar bill is made of good quality fibre, and they make a great gasket...although I'm not sure that the Euro/Danish currency is the same.

Never have used Viton before as a cylinder gasket, what is the maximum temperature rating. Superheated Gauge one engines produce temperatures in the cylinder chambers hot enough to turn steel blue.

You could also try just straight sealant, spread a very thin amount on two parts and place together. Make sure there is no excess inside or out.
 

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Dear Ryan

Thanks for your quick reply.

Hmmmm. I have an old Aster with superheater.
Guess Viton might be a problem. It can only withstand temperatures of 400 F/200 C.
Anyway do you know where I can order OEM aster gaskets? (sounds like aramid paper, with woven ceramic fibre is just what I need)

Regards

David
 

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Ok . Viton is fine for Orings but should not be used as gasket material where there is any chance of it getting burnt /overheated! it is Flourosilicate rubber anad if burnt produces Hydroflouric acid[ this etches glass and human flesh and doesnt wash off!!!!]. Go to a gasket supplier and you should be able to buy a 1mm thick sheeting , faced both sides with graphite powder and made from rag/ polymer, excellent sealing and will lift off metal faces without leaving crud.

Gordon.
 
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