Hole in cylinder wall

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Sarah

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Hi Guys,

I am after a bit of advice please.

I have a small blind hole half way down a cast iron cylinder bore. The hole is approx. 1/8" dia. across and 1/8" deep. Is it worth trying to fill the hole or is there anything else I can do?


Many thanks,

Sarah
 
If you are going to run it on steam, there isn't much you can do, except possibly bore the cylinder out and sleeve it. If you are going to run on compressed air, then you could try one of the epoxy based fillers like J.B. Weld. If the piston has rings on it, there is always the chance that the rings will catch on the edge of the hole and break.
 
Hello Sarah,
You say that the hole is blind. Is it due to a void in the casting? If so you might be able to open the bore a little more to get rid of the hole, and modify your piston to fit the new dimensions. You have to take into consideration the clearances of the ports so there will be enough material to incorporate them.

ART
 
cast iron does not weld well but a silver soldered plug could be an option.
If this is to be a working engine to power say a steam boat a sleeve like Brian
said may be a better choice.
How about an introduction in the welcome sub fora tell us a bit about yourself your shop and your interest in model building,and your location . this helps us help you .
Tin
 
I second Brian's comments. If it's only to be run on air, JB weld it and (after plenty of curing time) clean up the bore. If it's IC or steam, you're gonna have to sleeve it. Sleeve can be quite thin (.030 wall?) so you won't have to bore it out too much.
 
Hi Guys,

I've put a bit about myself on the Wecome thread :cool:

I will hopefully be running it on steam. Can anyone point me in the right direction to look at sleeving the cylinder.

Many thanks,

Sarah
 
Is this casting set a recent purchase from the original suppliers? If so they should replace the cylinder free of charge.

If not, sleeving is the best way to go. I have only sleeved gunmetal with cast iron before, it worked a treat. Bore the cylinder to take the sleeve, turn up a sleeve a good interference fit, put the liner in the freezer, heat up the cylinder, then make sure it goes in really quickly;).

Jo
 
If sleeving make sure you are not going to cut into any cast steam passages when you bore it oversize. As you are using iron piston rings than the sleeve is nothing more than a tube turned from cast iron that is a press fit into the enlarged bore, you can add a bit of high temp loctite if you are not sure of your fit

J
 
Hi,

The Bore and stroke are both 1 1/2". Apparently the casting set is quite old, the engine was built up and kept as a sort of display piece, but there are a number of machining errors on it. I have taken it to pieces to see if I can get it working. It needs new bearing blocks as there is an awful lot of play in them, along with machining a better fitting eccentric Strap. There are also no paper gaskets or gland packing.

It's an interesting project though :)

Sarah
 
Sarah said:
Hi,

The Bore and stroke are both 1 1/2". Apparently the casting set is quite old, the engine was built up and kept as a sort of display piece, but there are a number of machining errors on it. I have taken it to pieces to see if I can get it working. It needs new bearing blocks as there is an awful lot of play in them, along with machining a better fitting eccentric Strap. There are also no paper gaskets or gland packing.

It's an interesting project though :)

Sarah
Click to expand...
Hi Sarah,

The idea of sleeving the bore is a good solution, probably the best. However as has been said there is a danger of boring into the steam passages if you go too far.

Looking from another angle would the performance be too compromised if you reduced the size of the piston and sleeved the existing bore? From your description, personally if I were to attempt this and performance was not critical I would lightly skim the bore to clean it up, make an accurate thick walled sleeve and use one of the suggestions by other posters to fit it, then bore it to suit a turned down piston (I once saw an 18" diameter sleeve fitted into a loco cylinder for repair at a heritage railway, it was soaked in liquid nitrogen for several hours in a metal dustbin before fitting and the guys had to work fast, believe me). You would of course have to make new rings (if fitted) but that is not too difficult.

Regards
Terry
 
I've used JB-Weld with great success. Some people have even used it to successfully repair pitted bores in internal combustion engines. If it can tolerate ignition temperatures, it will most certainly stand up to anything your application will throw at it.

Orrin
 
In years gone by we used to fill blow holes with White metal(babbet) , melts about the same temp as lead use solder flux .
 
Tin Falcon said:
cast iron does not weld well but a silver soldered plug could be an option.
Tin
Click to expand...
Tin Falcon said:
cast iron does not weld well but a silver soldered plug could be an option.
Tin
Click to expand...
Thats true in general, You shouldn't expect much strength from such a weld.

But I've seen often enough how defects in new large castings were repaired by welding.
The defective area is removed with an angle grinder, or by milling if its large. A piece of cast iron is fitted into the gap and welded.

One thing is noticeable about welding: You can use basic sticks, the weld won't be much weaker than with special welding sticks. But You can't machine the weldng (exept grinding). Hardness is usually such that you don't have luck even with carbide tooling.
If you need to machine it you need special nickel based sticks. They are pretty expensive, 5-10 times higher priced than basic sticks. And they are not very "user-friendly" during welding.

Another point is to keep heat stress low during welding, only short welds at a time.

In general in industry they think twice before they scrap a new casting of several tons.

Mike
 
Frankly, if the bore is good, other than the blowhole, I would be inclined to ignore it, especially if fitted with CI rings, even with soft packing you will get away with it more often than not.
 
I tend to agree with Tel - suck it and see.

If the hole has a clear path to the outside you might consider drilling & reaming it out and plugging it with a drive fit pin turned to suit. Cleanup is a PITB though.

Ken
 
Hi Guys,

I'll sort out the other problems with the steam engine and try running it to see how it operates. If there is a problem I'll try the JB weld, then if that doesn't work I will investigate making a sleeve, though there is not much extra diameter to play with.

Many thanks,

Sarah
 
depending on where the hole is located you could drill and tap the area and thread a piece of brass and screw it in then cut it off just a little long and peen the end so to swell the brass to swedge it in place and dress off what has come through the cylinder wall.
 
Hi,
The hole is quite hard to get to as it is on the steam chest side. I have cleaned it out and filled it with JB weld. I'll find out when it's built if it works :)

Regards,

Sarah
 
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