Marcher twin cylinder marine steam

[Team ricky]

Hi Chaps,

I’m new here and wanted to share a nice build log of two lots of twin cylinder marcher engines

[Admiral_dk]

Don't think that I've seen this design before - but happy to see more 

Oh .... and welcome.

Per     

[Team ricky]

So I’m planning on building one as a piston valve engine and one as slide valve 


Should be interesting to try both out , I have just looked through the drawings and the piston valve version is a bit sketchy, When I get into it I’ll post some pictures !

[Team ricky]

So as far as I can see on the drawing there are two options within the piston valve configuration,

This makes for interesting building when you don’t know this in advance!

This picture details how you are not going to build the cylinders and piston 😂

[Team ricky]

This picture shows how it is to be built, however not very detailed for the piston valve itself as it needed a re-design….

The right side of the cylinder chest is to be cut off entirely, then the steam will come into the top of the cylinder via a banjo bolt, Problem is as drawn in the first picture the piston valve won’t work as there is no steam exit provided for in the lower half of the cylinder-piston arrangement.

I have made the cylinder chest as per second drawing, Then made the piston valve from ground SS stock and modified to allow steam to pass through the centre of the valve to the top to allow for a steam exhaust.

[Michael S.]

Hello,
I don't know, but I can't see any fault with the piston valve in the first picture. I think both directions of rotation of the motor will be possible. It works with external and internal inflow with steam. With the lower variant, the overall length of the motor is shorter, which is an advantage when used in model boats.

Michael

[Team ricky]

A bit more done today

I have made both identical piston valves with the hole down the centre to allow steam from the lower port to exit or feed as needed!  The last process is to drill a cross hole 1.5mm below the lower port position…

I also made a nicely fitting piston from phosphorus bronze with graphite yarn for the ring….

[Zephyrin]

but I don't see the problem you raise with the valve !

The only point I dislike with such a design is the lack of lap for the valve, required for the reversal of the rotation by inverting exhaust and steam intake, common in model engines but not very realistic, contrary to the slide valve version of this engine !

[Team ricky]

Hi,

Yes I see I didn’t quite catch all of the drawing!

The picture of the valve shown is good for making a part but isn’t suitable for the valve chests in the revised piston valve assembly, there is a picture of the correct valve but no dimms, and missing the cross hole ! It’s pictured inside the valve body and not separately to make it obvious there is a difference!?

Also made two piston rods and a cross head

The standards probably should be properly de-burred after the slots were cut as there are some small high spots inside, caught me out and I made the first one under size…

I’ll probably re-mount in the lathe, clock in, and very lightly skim with a boring bar …..

[Roger B]

Excellent work  That's not an engine I have seen before. Is it a US design?

[Michael S.]

Hello Roger,

I believe the castings for the steam engine can be purchased from Reeves.
I also wanted to build a small engine like this for a second steamboat. With a valve for reversing.
But then I found a German blueprint and then built this engine.
(At some point I'll change the many pipes. I think I can reduce that.)

Michael

[Team ricky]

A bit more underway

I got very distracted with building a boiler and a small oscillator engine !

I’m starting on the hardest work on this one ….. being stainless steel eccentrics 

[Team ricky]

And the boiler bits thus far

[cnr6400]

 

[Zephyrin]

good start with the boiler, bended tubes look fine.
what is the size of your boiler ?
2 double-acting cylinders make an engine thirsty for steam !
I saw a boiler plan in Model Engineer a long time ago; by J Bertinat, who designed the Marcher engine. I will look for references.
 
are you working on a cork surface on the workbench ? it looks so

[Team ricky]

Here’s the boiler ready to silver solder

A friend on the trade is going to solder it all up as I’m not well enough for fumes masks and all that !

The boiler is a mix of two designs which have attributes Im looking for , The boiler is a Babcock style with the added vertical flue tubes through the boiler shell, The idea is to have a central flue mounted on a flue cowl (low profile) I should get a lot of steam with a number 12 jet on a Bix style ceramic burner which I’ll make myself and test.

The boiler working pressure will be 50psi so a test at 120 psi should be good 😊

[Team ricky]

Hi Z,

Yes it’s a cork surface I like it because if I do wood bits I can pin to the bench and it’s easy to peel and replace !

The boiler is 2 3/4” diameter x 6 “ long

I haven’t calculated anything so just going on gut feeling really , which is where I get the most fun in hobby’s ….. I have also a quiet large Scotch return boiler with super heated manifold and wet steam manifold, That particular boiler can make a lot of steam but definitely requires a feed pump to get a good run time .. And a good amount of gas !

[Zephyrin]

nice to see that you are experimenting a personal design for a boiler...
Some years ago, I helped about half a dozen of friends with the brazing of their marine boiler, mostly of the internal butane flue tube type with water tubes in helical array crossing the flue, a very common design here; only 2 departed somewhat from this design.
I stopped this activity with the years (77 now) as brazing becomes too stressful, now, I simply discuss about steam around the pond (and at the bar too)  with modelers...just like in the forum !

[Team ricky]

After a bit of distractions elsewhere I did get on and make and eccentric!

A bit tricky in stainless 316 on my machine but it did do a good job 👍🏼

[Team ricky]

Hopefully the boiler has been pushed on a bit this week Silver soldering is the part a friend is helping with!


The engine I’ve done quite a bit more on , Made the eccentric’s , the straps completely, the eccentric rods and offered up the steam chests!

I thought to make a little registry lug from copper, form to the centre port and have it proud to engage the cylinder block port, That way I can pre-drill the chests and line them up and transfer punch the 4 holes perfectly !

[Team ricky]

A little more done today

It was more of a go over job ! I got the two marcher engines part way completed but decided to build a bigger Borderer from start to finish, After completing the crank for the bigger engine and spending a good amount of time dialing the crank during build I thought I better check the other smaller cranks and they were off by a fair margin, too much , so I decided to try and rescue the parts !

I was lucky because the error was the tail stock pressure which caused the output ends to be out so I tweaked the webs exactly at the roots to straighten them both ! Got 0.01 -0.02 , span them up and they are good ! Not perfect like the big crank I made but the fly wheels are steady and look concentric !

The bearings are good with no tight spots so I think I’m good ☺️

[Team ricky]

Here’s the crankshaft being Nickel plated just using house hold parts !

There are some YouTube vids on it and most just use:

Cheap mobile phone charger
Distilled white vinagar
99% pure Nickel
Salt

Pretty much what’s needed

I’ll post a pic later when it’s cooked long enough !! Around 2-2.5 hrs should be good 😊

[crueby]

Recently I've found that agitating the solution to keep the bubbles moving helps get a smoother surface, either tap on the container, or use a little submersible fish tank pump. Dont leave it in too long or it starts to get wrinkly.

[Team ricky]

Here’s the plating done ✅

[Team ricky]

A little more done ✅

Does not look like much but both big end brasses are made and fitted! A good tight fit but spins freely so I’ll take that and make the rods next

[Team ricky]

A little more sorted

Made both con rods and made one assembly ready to fit !

[Team ricky]

I’ve managed to complete some more jobs

Set up the rods and tested turning over , one small tight spot but with luck will run in …. Not serious in any way

I made the eccentric links and set up both, drilled and tapped for the valve chests , Made the cylinder nuts

Pretty much everything big made now and just down to pipe work and gaskets !!

Hopefully I will be able to steam test on the weekend!!

[crueby]

Great progress!   

[Team ricky]

Thanks !

Quick question for steam ppl….

The ports of the cylinders are called out at 1/8 tall if you will with 1/8 spacing between them

The piston valve is called out to block in/out ports in the centre of travel so far so good

Then the eccentric is called out to have 1/16” offset gives 1/8” total travel per revolution…..

Why only open the ports halfway ??

Odd…..

Piston valve wear? High rpm ?

I’m stumped

[crueby]

Hard to say what was in the mind of the designer. Once the surface area of the exposed port reaches the area of the passage behind it, opening farther really doesn't do much since the passage will restrict the flow. On a small scale model, the ports/passages really dont need to be very large to run well. I like to run my engines slow anyway, and the needle valve on the inlet doesnt need much more than barely cracked open, even on my larger engines, to get a nice running speed. It would be different for running at really high speeds with a large displacement engine. Its one thing we've noticed up at the logging museum on the steam Lombard (full size engines, about 8" bore). We have the reversing link only over to the first notch, so the valve ports are not opened that far and close early, and we still only move the throttle lever a fraction to get 19 tons of log hauler moving at 4 or 5 mph, since it was designed to pull 20 or 30 tons of logs, and we are running with no load behind it.

[Team ricky]

Thanks for adding your experience

Today I made the intake manifold and banjo bolts and banjos….

Too tempted by a compressed air run I tried!

It’s a fail as of now as it won’t run, gave it a good spin on the flywheel, adjusted timing slowly all the way to run in the opposite direction and never got more than 3 un aided turns ! Won’t even try to self start

I have No gaskets under the the lower cylinder covers and a little soapy water shows big leaks so probably a factor…. I will fit gasket’s and test but I’m not hopeful…..

Down the steam rabbit hole me thinks!!!

[Team ricky]

Here’s a short video showing where all the steam’s going!!

Effectively the pressure is just venting to exhaust

I re-made both piston valve to give 0.2 mm extra ‘Land’ over the ports thinking if the pressure is overlapping some, Does not seem any better and then the lack of eccentric travel starts to show up as the port not being open even with the piston still needing to travel down the bore….

Which leads onto the following issues I’ve found:

1) the crankshaft is scrap ( I didn’t make it ) - only gives 7mm total stroke as a pose to 11mm
Ordered material to make a new one.

2) The piston valves are made from ground stainless but slip in too easily in my opinion…
I’ve ordered 5mm silver steel to re-make another pair provided the material is tight fit - If no I’ll make the material to the tolerance needed and run them in …

3) replace the vitron piston rings just as a matter of course
I have material in stock and should eliminate any blow by

Beyond that lot I’m not sure what to do !!

The steam I think can’t be getting by the pistons at the rate in the video

I think the main issue is the piston valve tolerance to bore but we will see!

Lastly I probably will re-make the eccentric’s to give a 3/4 open condition vs less than half port open condition- even more important when I have the correct stroke as at present the port shuts as the piston is still travelling down say and that’s on 4mm reduced stroke!

[MJM460]

Hi Ricky, frustrating when an engine does not run, but most issues are solvable, the trick is to work out which issue is at the root of the problem.  I have a couple of thoughts which may help, help to avoid time wasting on unlikely issues anyway.

First, I would keep experimenting on air, it’s so quick to start and stop the compressor, and no waiting for heat up and cool down that makes each steam test more time consuming.  If it won’t run on air, it won’t run on steam.  On the other hand if it runs on air, steam is then straightforward.

It’s desirable to make the new crankshaft for the sake of efficiency, but I don’t think it will stop the engine running.  It will use more steam than necessary, and produce less power with the short stroke, but should run, as you are not really giving it any load.

The valve is normally made a little longer than just bridging the ports, this is called lead, and requires the timing to be adjusted so the opening starts very close to the end of the piston stroke.  This means the port closes before the piston reaches the bottom as you have noted, but that is normal.  The engine continues to do work to the end of the stroke after the valve closes as the air or steam expands.  No real difference in this respect.

The fact that the ports do not open fully also should not stop the engine running.  Again, it will affect the maximum power from the engine, when it is fully loaded, but again, should not stop the engine running, even if it requires more pressure than you would like for unloaded running.  When you have it running, you can try making an eccentric with bigger throw.

I have found a little leakage past the piston can be tolerated, but you don’t want the rings making the piston too tight.  Just check that it is not really loose.

I have not yet tried a piston valve, but the piston valve fit would be high on my list of suspects, I think engines are more sensitive to leakage past the valve than past the piston as this leakage steam does not do any work.  I have had the occasional issue with slide valves not seating correctly, and the resulting leakage definitely stops the engine from running.  So that is where I would start looking.  No doubt, others with more experience of piston valves will chime in here.  If you hold the flywheel and turn the engine to a little before bottom dead centre, where the ports should be closed, then the valve leakage will be visible and you will get a good idea if there is too muck leakage.

And of course, the valve travel needs to be set so the movement is symmetrical for the up and down ports.  And best to set the piston rod length so the piston travel is also symmetrical about the centre of the cylinder.

It may be worth removing the pin from the eccentric strap so you can move the valve by hand.  Moving the valve should move the piston up and down unless the leakage is excessive.  Then reconnect and reset the timing.

Unfortunately my iPad doesn’t want to run your movie, so I haven’t been able to view that.

There may be several factors at the same time, but you should see some improvement with each thing you fix.

I hope those comments help you find the key issues.  We are all barracking for you to get it running.  It’s usually small things at this stage.

MJM460

[crueby]

Hard to tell from the video where its blowing out the steam, though it looks like it might be at the bottom of the block, piston rod seals or valve rods?
I like to do leak checks with compressed air, a lot easier and safer on the fingers! At a low pressure, I'll use either bits of tissue to track them down, or water on a swab, usually shows the leak spots very quickly for ones on the outside at gaskets/glands/pipes/etc. Piston/spool valves are always tricky things, a very minor gap will blow a lot of pressure by. If you can tighten up the gaps enough to get rid of most of the blow by, it will run fine. Some leakage is not a problem, and any full-size engine I've seen running has some around the piston/valve rods. What I see in the video is too much though, but should be fix-able.
As MJM said, the piston valve is a likely suspect, either too poor a fit and blowing around it, or if either the center gap is too wide and bridging the ports, or the overall length is too short and not closing ports like it should. Again, putting it on compressed air and turning the crank over slow by hand should identify the issue pretty quickly.

[Team ricky]

Hi,

Thanks for your support and time

I went through a similar thought process re- finding the problem by changing ins thing at a time with the piston valve suspect number one !

I had a happy thought to nickel plate the piston valves until they won’t fit then polish them carefully and get a slip fit to run in !

The video if you get to see it shows pretty much all the steam bypassing and coming out of the exhaust ports at an alarming rate !!

I’ll try the plating first
New piston rings second
Re make eccentrics to give 3/4 port thro
Make a crank if I see a good improvement

I think you are right in saying I will get it running as it’s possible to eliminate issues one by one  ☝️

[Team ricky]

Here’s one valve coated …

I have since polished it and it comes up very well too tight to fit now which is perfect…. I’ll slowly polish down to a fit!

[crueby]

Now thats a neat idea! Never thought of that one, that saves a lot of work making a whole new one.   

 

[Kim]

Who says you can't put metal back on!  Ha!  You proved them wrong there     

Kim
 

[john mills]

I would not expect the piston valve to completely seal it will have clearance so it can move  .have look at full size engines full size sissan engine
when stopped quit a bit of steam will go out the exhaust they have a plain piston valve with clearance so will leak but when running work.
we would just like it to be minimal.
john

[Team ricky]

Yes there is definitely going to be some pressure loss due to design!

The short video was at 50psi and it won’t run…. It sure looks like most of the steam was bypassing straight to exhaust…. Just have to fully track that down …. The one valve I’ve plated I polished and fitted and is much harder to blow by now , Just need to make a second and repeat the process and see what happens

[Team ricky]

Good news on the replacement silver steel stock for the valves …

I’ve made one and pressure tested it in its bore and it’s a damm sight better! Not completely sealed as you’d expect but hard to get volumes past it ! Probably 3x better I’d say

[crueby]

Thats great!!

[Team ricky]

Here’s a short video just after putting better fitting piston valve in …

I’ve ordered some Teflon tube to see if I can sleeve the piston valve bores, It might not work so I went with I’d that will slip in the bores and I’ll make under size piston valves 

At least I know where to put time into the project! And I’m only 30/40% off good running

[crueby]

Thats MUCH better!!

[Kim]

Looks like it's running pretty nicely to me! 
Kim

[Team ricky]

It’s certainly not bad but could benefit from some more power if used in a boat !

When the boiler primed a bit of water I could still see blow past the valve to the underside (above eccentric)

And a bit of water bypassing to exhaust! So definitely a little more to go….. with the correct throw on the crank I’ll get a bit more torque also

[paul gough]

If you are only running on air or low pressure steam then graphite loaded teflon has shown itself a satisfactory material for a small piston valve. Might have to experiment to get a good seal and running fit but somewhere near smooth light push fit should come close. Regards, Paul Gough.

[MJM460]

Hi Ricky, congratulations on getting it running well.  Clearly the valves were a big part of the problem.

Now it is running, the new crankshaft will increase the power, remember the formula Power is proportional to P x L x A x N with a constant to allow for the irrational units usually used for these quantities.  You can see Power (and Torque) are directly proportional to stroke.  Increasing the stroke from 7 to 11 mm will give over 50% increase in torque and power, without much increase in steam consumption due to the increased efficiency with less clearance volume.

Looking closely at your drawings, the ports are specified as 3/32” not 1/8” per your earlier post.  And the piston valve lands must match the port width at 3/32” as shown on your drawing extract.  So the eccentric throw will still not completely open the ports.  However, the ports are shown as 1/4” wide, so do not need to open much to give a similar flow area to the passages in the steam chest which are only 7/64” diameter.  Increased flow area beyond this has diminishing returns.  Increasing the valve stroke increases dimensions of the valve chest and around the eccentric strap, so no need to make it larger than necessary.  I suspect this is the answer to your earlier question on not opening the ports completely.

In the original magazine write up, John Bertinat explains that the piston valve layout is for radio controlled reversing by an external valve which reverses the steam and exhaust connections.  For this configuration, the valve movement has to be symmetrical with no lap or lead and the eccentrics at 90 degrees to the respective main cranks.  The drawing then shows only .005” of lap each side of the port, which means slightly late steam valve opening, but probably a good compromise.  Remember the valve is only in that position for a tiny fraction of the revolution so steam leakage there is not a big factor.  The 90 degree crank orientation of the crankshaft should ensure self starting.  Its worth rechecking the port and valve dimensions, and the port locations if you still think the performance could be improved.

The condensate formed when warming up the engine has to be drained so a little valve leakage is good, indeed essential as John says above, but the lower end of the piston has no gland, equivalent to the valve rod gland on the normal slide valve configuration, so leakage is expected.  If it is too objectionable, a grove in the bottom land of the piston valve with a wrap of packing would reduce that.

Then perhaps a little fine tuning of the valve timing until you are satisfied.  If you are planning on running on steam, particularly if your superheater is good, I would not bother with the Teflon sleeve.

If I understand correctly you are also making a slide valve version.  Comparing the two will be interesting.

MJM460

[Team ricky]

Thanks for the reply’s gents

All good for thought !

Unfortunately the second engine has been ported for piston valve use so I don’t think the slide valve would work properly or at least not to drawing!

I am building a bigger all cast iron (where possible) Borderer slide valve which I think will be more interesting and looks wise be a lot more scale than Gun metal

I will at some point build the second Marcher using what I’ve learned so far….

If it’s possible to buy precision hollow shaft (Id being precise too) this could be a possibility as a piston valve chest/housing as reaming however careful seem to give a very slight taper if you have run out in the reaming operation, The hollow shaft can be silver soldered to a brass plate for mounting..

All options I’d like to explore before finishing the Borderer piston valve engine that at this stage in build

[MJM460]

Hi Ricky, that will make a nice group of engines and will allow you to experiment with various features to help you optimise the performance.

Looking forward to following your progress.
MJM460

[Team ricky]

Here’s the reverse valve and manifolds done ✅

Well to a degree!

The threads are under size so I need to make two stand pipes tighter to rescue the part …. These will be epoxy onto the threads and give a decent pipe for the nut and Union to bolt to…

I have also some Teflon so in investigating leaks I’ve decided to make two rings for the lower part of the piston valves as they leak pretty badly from the bottom , I’ll leave a gap for some water to escape but nothing like as much as present .

[Team ricky]

Well all a bit odd with this engine….

It ran well on compressed air without the reverse valve, fitted the valve and it rams both ways pretty well still no power but the new crank will help a little there …

During the run I put a little oil into the intake and after a minute or so it ran badly, would not reverse and is pretty much un usable….

So I made the grooves for the Teflon rings and fitted those to both cylinders… I noticed the previous Nickel plate on the one test valve all stated to come off !!

So I think I’m back to badly sealing piston valves … I ran the engine again on steam and it will run fast but zero torque, Ut didn’t clear anything or run better.

I think I’m going to have the valves professionally plated then I can polish each valve to suit its hole !!


Very disappointing set up with these valves since the home machinist can only ream a hole and buy ground stock and hope ! Well it’s less than ideal and I’m my case produced a scrap engine..

The only good thing to come out of the last day is my tap follower I made to fit my mill for hand tapping 7-8Ba

[crueby]

When I've done spool valves, the trickiest bit was getting a good slid8ng fit. Rather than depend on reamers and ground stock to match up, I started with the next size bar up and turned the spools down to size, taking very light cuts to sneak up on the size, lots of testing it in the bore, and leaving the bar in the chuck the whole time. To test, I  back up the cross slide out of the way to get room to test it in the bore. Final cuts were spring cuts, taking passes without advancing the cross slide in. Even then, sometimes had to start over. I much prefer d valves, but sometimes  a spool valve is what the design needs.

[Team ricky]

I may well have a go at that tomorrow
No harm trying one ☝️

I think what’s needed and if it’s possible to get could be precision tube (I’d) and I’d bet it would be alot easier to get a good fit with ground bar ! I’m pretty confident the reamer didn’t cut a totally parallel bore …. This is definitely giving trouble, So last resort and probably last thing this engine gets I 6mm reamer and another two new valves , failing that I’m not carrying on with it

[crueby]

If you have a good small boring bar, that can give you a good tube cut to the size needed to fit the ground rod. The tube walls need to be thick enough to chuck up without deforming for that to work (had that happen, learned that the hard way)

[Team ricky]

Thanks for the tips there

I patiently made my stock from 5.5 mm 316 stainless ,As you said crept up to dimension for each valve chest and then ground down till they both fitted very close indeed , They need care to break the burr on each part of the valve you need to do so,

A good learning curve because I had to further set up the accuracy of the tail stock to get pretty much perfect cuts over 3” or so and using spring passes to confirm the accuracy..

All in the engine now runs great again on my rubbish tyre emergency air pump (14 psi)


I’ll next re-establish the reverse valve then wood cladding then the new crank which should give a usable model

Oh and I think I’ll buy a small quiet compressor for running things in ect !

[crueby]

Excellent!




One compressor  type worth looking at is the line of small ones from California  Air Tools, quiet enough not to need earplugs like most. I  got mine years ago, there may well be other brands as quiet now.

[Kim]

A second vote for the California Air Tools compressors.  It's very quiet compared to my other compressor.  I certainly wouldn't call it silent, but it is orders of magnitude quieter than a standard compressor!  I've also had mine for many years.

Kim

[Team ricky]

Cheers for the heads up


I’ll have a look around , my constraints are living on a boat so it will have to be small !

I did finish the lagging and the wood cladding bar two brass strips !

Looks good , runs both ways on low pressure compressor so I think just a crank when I’m ready and hopefully it’s usable

[Admiral_dk]

A fine looking little Engine 

Will it be mounted in a boat ?

Per       

[Team ricky]

Hi Per,

Yes one day ! I’ve got a mahogany rc boat to finish first, I get side tracked pretty easily!

I think I will set up a base to run it on for now and display

[Team ricky]

A little vid of the engine reversing and on 14psi air !

Please excuse the Gregious noise !!

[Admiral_dk]

That is certainly moving - but at the most likely Propsize, that is also needed 

Per   

[Team ricky]

To be fair to the engine it is now making some power !

You can’t easily stop the engine via the 1/4” shaft in either direction….
I’ll check it on steam and see if it will run at say 10psi and if it’s got good power at 45psi I may call it and crack on with the bigger version of course making good valves again will be key