# Horizontal shaft VS Vertical shaft (small) engines.



## tsaw

When it comes to the design, the vertical shaft engine is superior.

Here is why:

Oil delivery.

The horizontal design puts a little "scooper"  on the bottom of the connecting rod's end cap. There must be enough oil in the crankcase for it to reach it, and splash it all over the inside of the crankcase - and lubricate the moving parts.  So, for example: If you have a engine with that setup that has a 26 oz oil capacity, and it falls below the reach of the scooper.. it will seize or fail due to lack of lubrication.

The vertical shaft doesn't need a scooper because the crankshaft is not above the oil, it is going right through the bottom of the crankcase.
So, even if there is only 2 OZ of oil left in there - the spinning shaft is in that oil, and that will "whip up" enough to throw oil the the rest of the engine.

The reason I know this is true - is because I had yet another (seen this many times) lawn mower come in for a tuneup - That had no oil show up on the dipstick. Draining the oil provided about 2 OZ!!! That is 18 OZ low!!
No mechanical damage. Just very low on oil.
You could never get away with that with a horizontal shafted engine.

Anyone agree?


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## Trakternut

My wife's friend called, one after noon, saying that her mower (vertical shaft) had stopped running and she couldn't pull it over with the rope.  I went over and checked it out. 
I pulled the plug wire and tipped it over to turn the engine over with the blade. It was very stiff. I put it back on its wheels and tinkered with the recoil start a bit, then checked the oil level. Danged near dry!  I found some oil in her garage and filled the crankcase. This all had given the engine about 45 mins. to cool down. I turned it over with the blade again, feeling the engine turn more freely with each revolution. I put the plug wire back on, started it up and she finished mowing her lawn.

You may be onto something, Mr. Saw!


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## AAUTOFAB1

sounds like the vertical engine is just better for the idiots that don't check the oil,i have a garden tractor, sears st16 (1973)original engine, that is still going strong,and i change the oil every spring.... now i have done a lot of work to it to keep it going over the years but never had an issue with the engine internals, yes it smokes a little on start up and I've had to buy a carb and new fuel tank,fuel pump,belt brgs,but the thing just won't die(knock on wood)all the newer riding mowers seem to be vertical shaft engines and you may be right,but they are defiantly not built like mine.


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## Trakternut

AAUTOFAB, an engine of that vintage is built like a brick sh*thouse to begin with. You've given it some care which has done a lot toward its longevity, but by its very nature, it's gonna be a toughie.
The modern verticals are not built to the same standards as yours.

I love them old horizontals better than the new verts, I'll tell ya that!


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## AAUTOFAB1

Well Monte,it does have a 1/4" thick framebut i do think Tom has a point about the newer vertical shaft engines,they need to be idiot proof,most people now days are just mechanically inept.JMO


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## bczoom

AAUTOFAB1 said:


> Tom has a point about the newer vertical shaft engines,they need to be idiot proof,most people now days are just mechanically inept.JMO


And that's why they put low-oil shut-off's on them.


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## fogtender

Having tore all of them apart over the years for a varity of reasons.  I think stupidity of the owner has more to do with the engine's long life or not.  

People use to (still do on some models) run with the choke on which not only fouled the spark plug(s), but allowed too much gas which would wash out the cylinder walls and thin the oil to where there was no lubrication for either design.

To circumvent "Stupid", most small engines now have low oil limit switches that stop the engine before "Stupid" can do more damage.  Having said that, I think that both style of engines have pluses and negatives, most applications depend on what the engine is driving and what kind of shaft design is needed.

JMHO though.


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