Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: logoman on August 31, 2010, 10:40:38 am
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The manifoild on the Aster marine engines is attached and sealed with silicone. During my attempts to rectify problems with this engine, i have removed the manifold. I would have liked to have found an alternative to the silicone when reassembling the engine, but have not been successful, with leaks on the middle cylinder. I tried paper gaskets, teflon gaskets, and gasket compound. The six screws that pull the manifold to the face are not sufficient to make the seal. Therefore I need to use an adhesive as Aster had done: white or clear bathroom silicone.
To gain a good seal the manifold will need to be clamped to the cylinders whilst the silicone is setting, but to do this i need to take the rail off the other side of the cylinders. I cannot work out how to do this, When i turn the hex nuts they spin, perhaps they are ornamental. I tried to knock the bar out of the eyelets without success. Also, when clamping the manifold, I am concerned that some silicone may enter and block the inlet/outlet ports.
(http://farm5.static.flickr.com/4142/4944785106_00fcb08780_b.jpg)
(http://farm5.static.flickr.com/4115/4944779610_9f3c23a322_b.jpg)
(http://farm5.static.flickr.com/4095/4944198975_2db0da4950_b.jpg)
(http://farm5.static.flickr.com/4138/4944780352_bb11bf02e1_b.jpg)
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Hi logoman..........
1. the manifold appears to have securing screws @ say 1.00 o'clock & 7.00 o'clock only
2. the enegine side plates appear to have tapping's @ 11.00, 1.00, 4.00 & 7.00 o'clock
Could you be getting some distortion there....& not sealing across the full face of the port? >>:-( .....Derek
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You need to lap the port faces flat with each other and also check the manifold plate is flat. A paper gasket should seal it, cigarette paper is only 2 thou thick, yes, fiddly but possible.
Regards Ian.
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The gap (leak) at the lower part of the center port is perhaps .3mm. When the upper screw is tightened. the gap at the bottom opens, when the lower screw is tightened nothing improves - it does pull a little, but I think the port thread was damaged when I tried tightening it to close the gap. Whilst I have considerable flattened the port faces, the design of the manifold (protruding pipes) means that no amount of lapping will make any difference. It is a design fault, no doubt, but I believe that it has been designed so that the seal be made between the protuding parts of the manifold and the ports holes.
Derek, the cylinders have four holes so that they can be mounted either end up/down : the casting are symmetrical top/bottom.
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Hello Logoman . :-)
It looks like you have four port holes on each cylinder , apart from the in & out ones.
Are they all threaded? If not, may be good to tapper them all ,same size. You have room for bigger size in case you need.
I wouldn't recommand silicone or coumpound here.
If so , drill extra holes in the manifold plate and with oily paper gasket, it should make it.
The leak is what makes the steamer's life exciting ...............................and wears out his nerves & patience! >>:-(
When we see you on Blue forum??? ok2
Hope you run this nice engine soon! Another good example of your collection. :-))
Cheers
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Did you try Hylomar sealer?
To remove the bar you also need to remove the brass cylinder covers fro the sides.
If none of your solutions have worked, something more radical is to cut the manifold in 3 parts, so that each mates with the corresponding cylinder.
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Did you try Hylomar sealer?
To remove the bar you also need to remove the brass cylinder covers fro the sides.
If none of your solutions have worked, something more radical is to cut the manifold in 3 parts, so that each mates with the corresponding cylinder.
Hi Calin, yes tried Hylomar, it made no difference.
please could you explain the need to remove the cylinder covers, I don't understand how these can be removed without first removing the bar and the three holding pins.
I don't see the need to modify this engine if I can return it to it's original state.
JUST NOTICED THAT I HAD NOT POSTED A PICTURE OF THE FACE OF THE MANIFOLD SHOWING THE PROTUDING PIPES! APOLOGIES.
(http://farm5.static.flickr.com/4098/4944781434_faf3c85a45_b.jpg)
(http://farm5.static.flickr.com/4045/4387860608_3582524af2_o.jpg)
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When we see you on Blue forum???
Hi Yves ;)
what is the Blue forum?
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Success in removing the bar - the bar is set in the eyes with adhesive, it needed more force than I'd applied previously. the eyelets can then be simply unscrewed from the brass cylinder covers (thanks Calin :-))) . All the problems with this engine are caused by its unconventional construction & materials.
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have you ever put a straight edge across the three cylinder faces to see if they line up ?
Peter
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All three cylinder faces can be aligned, since they rotate on their support. The manifold is another matter, and it's clear that the middle cylinder needs more gasket material than the others. There is little chance of correcting the shape of the manifold.
(http://farm5.static.flickr.com/4122/4945310486_0fd71ed580_b.jpg)
(http://farm5.static.flickr.com/4095/4944735185_bc5583beb7_b.jpg)
(http://farm5.static.flickr.com/4094/4945323294_7a4813a719_b.jpg)
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Rather than trying to use a gasket how about an O ring round each of the pipes. Obviously there will be a gap between the manifold plate and the blocks. The only problem I can see is that the O rings on the inlet pipes could blow out, but this could be cured by placing some thin rings around them.
An alternative to O rings would be to cut some narrow slices from silicone tube. It's very soft material and will compress nicely. I use this method to seal my water gauge glass. If you thread a piece of wooden dowel or a piece of brass rod through the tube, you can rotate it against a sharp knifr and produce really accurate rings.
Thinking about it I would go for the silicone tube slices.
Malcolm
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that's a great idea Malcom, THANKS :-))
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Hello Logoman! :-)
Seing the pipes protuding the plate's manifold, Malcombeak's idea is very good. Eventualy I would enlarge the ports (in & out) to O'ring size to make sure that they do not pop off. 1mm enough.
Still I do not understand why there is 4 ports per cylinders and only 2 in the plate to hold it? %%
Blue Forum? But you are famous there , dear! O0
http://modelismenavalradioc.nouvellestar6.com/modelisme-bateau-a-vapeur-f10/groupes-vapeur-t1393.htm
Regards. ok2
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I see they have a Bunkerbardge picture 2nd one down.
peter
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Malcolmbeak's idea with the o-rings is very good. Cutting them out of silicone tube lets you also adjust the thickness to compensate for the differences in port face location.
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:-))Give oven cooking paper a go I have tried it works a treat for gaskets
John
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Back when I used to do gas engines we would use $1.00 bills as gaskets, can't afford to do that now are smallest bill is now a fiver.
Regards,
Gerald.
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Blue Forum? But you are famous there , dear! O0
As he is with his friends--Miles collection and his manner make a great combination!! I know I am happy to have run into him...and his many engines... :-))
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As he is with his friends--Miles collection and his manner make a great combination!! I know I am happy to have run into him...and his many engines... :-))
Thank you for the kind words, I suspect though, that my collection is simply compensation for a lack of something, and a bolster to the ego. An uncomfortable feeling.
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I am confused as the the use of the nut on the bolts that fix the cylinders to the casting. what is the correct use of a fixing like this? is it a lock nut?
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I've bit the bullet, a rebuild of just the three cylinders, leaving everything below untouched besides re-alignment of the frame. I have been scared of doing the timing, but I've studied this engine for so long now i feel confident I can put it back together (never one of my strong points ). Since I have the manifold that was attached with silicone sealant off, I may as well.
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Well, I should have known this, but I hadn't studied the diagram well enough, but the piston rod gland is completely hidden within the cross head guide, so now i can make new seals for these, repack them and put some thread sealant on them too.
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Good luck be with you Miles...and a handfull of extra patience!
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well, the luck didn't get here quickly enough Greg. :((
Exactly what I had feared, happened. Whilst setting the position of the slide valve the grub screw slipped in the thread. It does not tighten now .
I suspect one turn of the thread on the valve is damaged, since when the valve is not on the spindle the grub can be screwed further in and holds.
the pointed grub is M2 and about 2mm
I don't know what to do about this.
(http://farm5.static.flickr.com/4145/4960567095_c5ef6c25fd_b.jpg)
(http://farm5.static.flickr.com/4145/4960565125_ab50a38bf1_b.jpg)
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So the grub screw is "stripped" and will not tighten or the grub screw binds and you cannot tighten it enough to hold the valve in place?
If the former is the case- the hole can be re-tapped slightly larger and a new grub ( also slightly larger) screw can be used.. if the latter- a tap can be used to clean up the threads??
Fingers crossed for you Miles --breathe......
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logoman ...all is not lost.......if the M2 tapping is stripped.....the tapping drill size for an M3 tap is 2.5 diameter.........if you did not want to go down this path....you could drill out the damaged thread & silver solder a bronze/brass plug into the hole ..........redrill & retap M2..... {:-{ Derek
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Hi Derek. Thanks for the advice, I would retap to m3, that would be simple, but I'm not sure how good I would be at shortening a grub screw. Would that be a case of filing one down? Would I need to make a point on the end as per the original?
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Hi logoman........suprisingly.... O0 I find the local model shop with DUB-RO products very cost competative
An M3 tap & tapping drill was about AUD$3.50...........DUB-RO part number #372........which is good value
You can also purchase DUB-RO M3x5 long carbon steel hollow pointed grub screws....however I do not use these after securing a bag of twenty only M3x3 long Grade 304 S/S HPGS for AUD$0.23 cents each
Remember the format is "hollow pointed grub screw" ....not set point....so you should not need to revise the gripping format........ :-)) Derek
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Frazer (Helequin) very kindly made me some more valve buckles, including the tiny grub screws. A much appreciated gesture, and very precise workmanship, thanks Frazer! :-))
So I finally got time to look at that center cylinder steam chest, and what a mess! The port face is very badly damaged, I suspect corroded by a cleaning agent used in the engine at some point.
(http://gallery.myff.org/gallery/877441/IMG_2700.JPG) (http://gallery.myff.org/gallery/877441/IMG_2700.JPG)
(http://gallery.myff.org/gallery/877443/IMG_2695.JPG) (http://gallery.myff.org/gallery/877443/IMG_2695.JPG)
Also removed and replaced the old graphite packing on the glands.
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Hi Miles,Glad to have been able to help a fellow steam addict.Looks like you are going to be busy. O0
best wishes Frazer
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Hi ,
Looks as though you are in deep trouble , I have never seen such a poorly designed cylinder and steam chest.
Firstly the very poor quality of material, we used to call it POP METAL or SPELTER, very soft and rubbish to work with.
Secondly how is one supposed to get down to the ports to maintain the face as the steam chest is cast with the cylinder and can't be removed.
I think that this may have been caused by dirty water going into a boiler and grit carried over by the steam.
Are the other port faces in such poor condition, this may have been your original problem with steam leaks through the exhaust, I assume by the look of the engine that it is quite old it has that nice used look about it.
Can I suggest that you get in touch with the maker and see what they can do to repair the damage, although cost may be prohibative.
If not do you know anybody who could machine off the steam chest down to port face level, flatten the face , make a detachable steam chest and reassemble.
It will be interesting to see how you progress.
George.
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That's a strange metal to make a cylinder of. Especially since the rest of the engine is really nice.
Is it really that soft?
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Hi KNO3.
I'm not sure what the actual metal it is, but it's a base metal that is used in Die Cast model cars and as far as I am aware was used in the Lost wax casting process.
The designer of this engine has nothing to be proud of as I see it's used in other parts of the engine and how you are supposed to repair damage such as this is beyond me, and if it's like that for 1-cylinder what like are the other 2.
Also when you read the beginning of the thread about the manifold that has to cover 3- cylinders, if it was mine I would cut the manifold into 3-parts.
I do feel for Logoman as I don't think he has the machinery to modify the cylinder, what puzzles me is that when you look on Logoman's you-tube web site
the engine is running very well, how I don't know if the port faces are like the one he shows.
George.
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believe me George, this engine is a trial!
Nevertheless, I enjoy working on it even though I have spent many hours encountering it's pitfalls and new 'challenges'.
I am determined to have it working again, despite my lack of tools or place to use them.
I believe you are right, it is spelter, thanks for pointing that out.
The other two cylinders are not so bad, since I cleaned them long ago, but that middle one has been slowly getting worse as a result of my hesitance to rebuild the engine,
primarily because one i set the timing in that middle cylinder again, it's a long way back to change it once I've re-bonded the manifold back on.
My theory is that after having the engine running well, I encountered some unusual corrosion on the boiler, and in an effort to clean it i used a strong solution of Calgon, and I must have not flushed it out somehow, and some was carried to the engine and then left there, a short time in the outside cylinders, a long time in the middle one.
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It has taken many hours, but I got there in the end.
I found that using silicone sealant, as the engine originally used, was my best bet for sealing the manifold.
http://www.youtube.com/watch?v=hV7Lq22-qqo
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That's great, it seems to run quite well. Does it run at low rpm too?
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yes
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Congratulations,its nice to see it running again you're perseverance has paid of.
best wishes Frazer