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[mogogear]

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......

[derekwarner]

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

[logoman]

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?

[derekwarner]

Hi logoman........suprisingly.... 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

[logoman]

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.





Also removed and replaced the old graphite packing on the glands.

[frazer heslop]

Hi Miles,Glad to have been able to help a fellow steam  addict.Looks like you are going to be busy.
best wishes Frazer

[ooyah/2]

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.

[kno3]

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?

[ooyah/2]

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.

[logoman]

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.

[logoman]

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

[kno3]

That's great, it seems to run quite well. Does it run at low rpm too?

[logoman]

yes

[frazer heslop]

Congratulations,its nice to see it running again you're perseverance has paid of.
best wishes Frazer