Rough and Tumble Engineering

by James H. Maggard

Now, turn the engine over till it nears the other center, and proceed exactly as before, remembering always to place the straight end of tram exactly in same place in block, and you will find both dead centers as accurately as if you had all the fine tools of an engine builder.

You are now ready to proceed with the setting of your valve, and as you have both dead centers to work from you ought to be able to do it, as you do not have to depend on your eye to find them, and by the use of the tram You turn your engine to exactly the same point every time you wish to get a center.

Now remove the cap on steam chest, bring your engine to a dead center and give your valve the necessary amount of lead on the steam end. Now, we have already stated that we could not give you the proper amount of lead for an engine. It is presumed that the maker of your engine knew the amount best adapted to this engine, and you can ascertain his idea of this by first allowing, we will say, about 1/16 of an inch. Now bring your engine to the other center, and if the lead at the other end is less than 1/16, then you must conclude that he intended to allow less than 1/16, but should it show more than this, then it is evident that he intended more than I/I16 lead; but in either case you must adjust your valve so as to divide the space, in order to secure the same lead when on either center. In the absence of any better tool to ascertain if the lead is the same, make a tapering wooden wedge of soft wood, turn the engine to a center and force the wedge in the opening made by the valve hard enough to mark the wood; then turn to the next center, and if the wedge enters the same distance, you are correct; if not, adjust till it does, and when you have it set at the proper place you had best mark it by taking a sharp cold chisel and place it so that it will cut into the hub of eccentric and in the shaft; then hit it a smart blow with a hammer. This should be done after you have set the set screws in eccentric down solid on the shaft. Then, at any time should your eccentric slip, you have only to bring it back to the chisel mark and fasten it, and you are ready to go ahead again.

This is for a plain or single eccentric engine. A double or reversible engine, however, is somewhat more difficult to handle in setting the valve. Not that the valve itself is any different from a plain engine, but from the fact that the link may confuse you, and while the link may be in position to run the engine one way you may be endeavoring to set the valve to run it the other way.

The proper way to proceed with this kind of an engine is to bring the reverse lever to a position to run the engine forward, then proceed to set your valve the same as on a plain engine. When you have it at the proper place, tighten just enough to keep from slipping, then bring your reverse lever to the reverse position and bring your engine to the center. If it shows the same lead for the reverse motion you are then ready to tighten your eccentrics securely, and they should be marked as before.

You may imagine that you will have this to do often. Well don't be scared about it. You may run an engine a long time, and never have to set a valve. I have heard these windy engineers (you have seen them), say that they had to go and set Mr. A's or Mr. B's valve, when the facts were, if they did anything, it was simply to bring the eccentrics back to their original position. They happened to know that most all engines are plainly marked at the factory, and all there was to do was to bring the eccentrics back to these marks and fasten them, and the valve was set. The slipping of the eccentrics is about the only cause for a valve working badly. You should therefore keep all grease and dirt away from these marks; keep the set screws well tightened, and notice them frequently to see that they do not slip. Should they slip a I/I6 part of an inch, a well educated ear can detect it in the exhaust. Should they slip a part of a turn as they will some times, the engine may stop instantly, or it may cut a few peculiar circles for a minute or two, but don't get excited, look to the eccentrics at once for the trouble.

Your engine may however act very queer some time, and you may find the eccentrics in their proper place. Then you must go into the steam chest for the trouble. The valves in different engines are fastened on valve rod in different ways. Some are held in place by jam nuts; a nut may have worked loose, causing lost motion on the valve. This will make your engine work badly. Other engines hold their valve by a clamp and pin. This pin may work out, and when it does, your engine will stop, very quickly to.

If you thoroughly understand the working of the steam, you can readily detect any defect in your cylinder or steam chest, by the use of your cylinder cocks. Suppose we try them once. Turn your engine on the forward center, now open the cocks and give the engine the steam pressure. If the steam blows out at the forward cock we know that we have sufficient lead. Now turn back to the back center, and give it steam again; if it blows out the same at this cock, we can conclude that our valve is in its proper position. Now reverse the engine and do the same thing; if the cocks act the same, we know we are right. Suppose the steam blows out of one cock all right, and when we bring the engine to the other center no steam escapes from this cock, then we know that something is wrong with the valve, and if the eccentrics are in their proper position the trouble must be in the steam chest, and if we open it up we will find the valve has become loosened on the rod. Again suppose we put the engine on a center, and on giving it steam, we find the steam blowing out at both cocks.

Now what is the trouble, for no engine in perfect shape will allow the steam to blow out of both cocks at the same time. It is one of two things, and it is difficult to tell. Either the cylinder rings leak and allow the steam to blow through, or else the valve is cut on the seat, and allows the steam to blow over. Either of these two causes is bad, as it not only weakens your engine, but is a great waste of fuel and water. The way to determine which of the two causes this, is to take off the cylinder head, turn engine on forward center and open throttle slightly. If the steam is seen to blow out of the port at open end of cylinder, then the trouble is in the valve, but if not, you will see it blowing through from forward end of cylinder, and the trouble is in the cylinder rings.

What is the remedy? Well, if the "rings" are the trouble, a new set will most likely remedy it should they be of the automatic or self-setting pattern, but should they be of the spring or adjusting pattern, you can take out the head and set the rings out to stop this blowing. As most all engines now are using the self-setting rings, you will most likely require a new set.