The previous engine installation had the coolant overflow container, mounted on the engine compartment sidewall, positioned so that the containers mid-point was level with where the hose that connected it to the base of the coolant filler cap on the engine.
The reason was so that the transparent overflow container also served as a sight gauge of he coolant level of the engine. Additionally, it was explained that if the container was below this point it could potentially syphon the coolant out of the engine or, if placed above could lead to fluid spilling from the coolant service point if the filler cap is removed.
When my beta 60 was installed this was not a consideration and the coolant overflow container was mounted higher than I thought it should be. I was told its placement was not an issue.
Does anyone have any of thoughts or advice on this?
Your Beta cooling system is closed by a cap that resists the expansion by heat of the coolant until a pressure determined by the construction of the spring is reached. Then the spring lets a "tiny" amount of coolant pass out the "overflow" hose. The engine runs happily at it's running temperature, coolant hot and expanded. When the engine is off and cooling down the liquid contracts and the pressure drops to zero then a tiny vacuum is created by the contraction. Then the cap allows fluid to be sucked back into the engine from the hose.
On my Honda Accord with a 1500 cc engine I think the total volume that moves into and out of the overflow tank from cold to hot and back to cold is about a cup and a half. On my Beta 14 with a 479 cc engine the expansion and contraction seems to be on the order of a tablespoon or two. The Beta has only moved the bubble in the 1/4" hose a few inches! There is just not that big a difference in volume of the coolant in machine that small.
Because the spring in the cap is the gate keeper it makes no difference if the hose to tank goes up or down. Every car on the planet has the tank lower than the radiator cap. I installed mine on my Beta 14 higher so it wouldn't interfere with the oil filter. The minuscule amount of expansion pushes a bubble up the tube an inch. I keep the tank just in case my engine overheats - again- the coolant will be in the tank and not in our wonderful gel coated catch all molded sump.
Seems to me that your previous engine installation was correct and that is exactly how I have installed a coolant overflow container with my Beta 38. It is very helpful to be able to monitor coolant level just by glancing at the coolant container.
With the coolant connection at the bottom of the container like your diagram shows, raising the coolant container above the pressure cap would allow coolant to flow out of the container and over the pressure cap neck when the pressure cap is removed--undesirable.