The excited youth had just mounted his vertical engines sideways. He had ingeniously mounted it to a board. He had a simple belt drive set up for the go kart he was planning to run it on. He’d done all the things necessary to get this engine to run horizontally, he had changed the connecting rod so that it had a dipper on it now, he positioned the carburetor so that it would operate with the engine running horizontal, he had put on a heavier flywheel. The engine ran beautifully, until it was engaged to run the go kart. At that very moment when the go kart engine was engaged the rod broke and came out the side of the engine block.
What happened here? Why didn’t this engine run? Can a vertical engine run horizontally? These questions and more ran through the youth’s mind as he contemplated the smoking engine.
The grand old question: are vertical engines able to run horizontally? The answer is yes and no.
If you are talking about a two cycle engine then the answer is yes, it can run horizontally with a combination of a diaphragm carburetor.
If you’re talking about a four cycle engine answer is 90% of the time, no they are not designed to run horizontally. The question is why are they not designed to run horizontally?
The reason why a vertical engine will not run horizontally is that the inside of the engine is designed to run vertical. Let me explain. Typically on a vertical engine there are two different types of oil dispersion devices: one, an oil pump that actually runs off a camshaft; two an oil slinger that runs off a camshaft.
Additionally internally the valves spring-cam-lifter interface has the deflector plates designed into it typically. In horizontal engines the cam interface shielding is different allowing oil to be displaced in different manners. This can affect the valve performance.
Also the bearings, especially the bottom bearing is designed to be immersed in oil at all times and the horizontal engine may not provide the same amount of lubrication that the vertical engine demands.
The connecting rod primarily is different in configuration. On the horizontal engine the oil displacement method is typically to use a dipper at the end of the connecting rod. The bottom of the vertical engine may not be the same amount of oil capacity and therefore will not provide the amount of oil cooling that is necessary when it is in operation.
Though the engines look similar internally they are different. Again the connecting rod on the vertical engine does not have a hole like the horizontal engine which has a hole in the top side of the connecting rod to allow oil to penetrate into the journal section. The correct size connecting rod with this hole is required if the engine is to be turned horizontal. Additionally the positioning of the hole for the oil to penetrate into the journal section is necessary to be on the correct side of the engine. This positioning of the holes is related to the oil dipper on the end of the connecting rod.
The primary reason why the vertical engine cannot run horizontal is really lubrication and temperature management. If you understand that these are the two concerning issues about why vertical engine is not designed to run horizontally and you have addressed those concerns when you’ve converted your engine then everything should work out fine. Careful management of the oil level and the oil quality need to be monitored.
From a temperature management standpoint it is difficult to monitor temperature other than to put a probe of some sort on top of the engine head. This may be a costly commodity. A poor man’s method of temperature my management is to see if the engine has trouble starting after it has been run for a period of 10 or 15 minutes. Also smell for knocking and pre/ignition.
Bottom line it is best to come up a method that will allow your vertical engine to run vertical, not horizontal. The go kart building 202 course shows you how to use a vertical engine and the simple steps needed to make it run a go kart.