Inverted Engine

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Inverted Engine

Post by werner » Fri 14 Dec 2018, 19:44

On a Fb page this bike with upside down engine was posted.
Two of the commends on 'Why" was,

For the same reason racers flipped ford flathead v8’s upside down

It’s called an inverted engine
And aircraft have been using them for years

No real reason is given that makes sense and as racers flipped their Ford flatheads, some one on here might give me a sensible reason.

Allso can it be done to a road car

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Re: Inverted Engine

Post by IndianaJones » Sat 15 Dec 2018, 00:16

Can't comment on the Ford Flathead, but in the case of this motorcycle, my guess would be to improve cooling.

You would notice that it is aircooled, inverting the engine would definitely cause "regular" sump to become a dry sump, eliminating frictional losses from the crankshaft, although I don;t know how they keep it from filling the piston skirts, and in effect turn the cam covers into the sump, the added oil flow there could affording better cooling to the cylinder head.
Plus in that location, the heads probably have more air-flow through them.
They have reversed the intake and exhaust as well, the hot air from the exhaust is now to the rear, and not passing over the cylinder head.

Another possibility is if the cylinder heads are heavier than the bottom-end, the inverted engine could have a lower center of gravity, but not sure what they did with the gearbox.

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Re: Inverted Engine

Post by werner » Sat 15 Dec 2018, 17:08

It looks like the bike has been built for racing, so might be that the builder was trying to get it running cooler. Might even only been built to be a show bike.

About thr flathead I found two threads about one car and the original page they refer to does nor exist anymore. ... 65479.html

Just a little article that I saw that might be of interested to some of you guys.

Now this, this is creative engineering
In the early days of midget racing, dozens of different engines were used. A few American passenger car engines would meet the displacement limits of 100 to 140 cubic inches set by most racing groups. Foreign engines and outboard boat motors were used as well as industrial motors. Outsized engines were sleeved down or "simply" cut in half. There was no limit to the ingenuity and innovation of the midget pioneers. For the most part, this all ended with the advent of the Ford V8-60 horsepower engine in 1937. Here was an ideal powerplant—one that would dominate non-Offy midget racing for nearly 30 years.

In Denver, the V8-60 didn't end innovation—it became more so. The Shay-VenDersahl V8-60 ran upside-down and backwards! Buddy Shay had been running a midget with a sleeved down Chrysler Four on local tracks. It was fast becoming obsolete so something had to be done. Two options were available to Shay—an expensive Offenhouser racing engine or a V8-60. The Offy would fit fine in the Shay midget but would not fit Buddy's budget. The Ford fit the budget but not the midget—it was so wide that it would have to be mounted too high in the chassis.

Shay's friend, Frank VanDersahl had the answer—mount the V8 engine upside-down in the car. Automobile engines are not designed to run inverted but that didn't bother Frank VanDersahl and Buddy Shay. There was no choice but to run the engine "backwards"—that is to use the (more accessible) exhaust ports as intake ports and the intake ports as exhaust. This was not unheard of with the V8-60 and the larger Ford or Mercury V8s but Shay and VanDersahl were probably the first to do this. At some point, it was decided to also reverse the rotation of the engine.

With everything upside-down, lubrication could be a problem but it all worked out just fine. Oil was picked up by channels in the pan and allowed to drain to the low point in the engine where the gearbox driven sump pump lifted it to a tank in the cowl. From here, the standard Ford oil pump took over. Buddy Shay reported that there was no problem with the engine and that it did not foul plugs. Shay had some sort of sponsorship with Perfect Circle and this is a heck of a testimonial for that product.

An aircraft carburetor of forgotten make was used and a Ford distributor was modified to run backwards. The valve timing of a Winfield racing cam may not have been ideal but it worked. With the exhaust coming out the bottom of the engine, things got a bit crowded and ground clearance was very limited. The reverse engine rotation was taken car of in the driveline by turning the rear end center section upside-down.

The radical engine design resulted in a couple of advantages. The exhaust gases exited very quickly and this was a rare V8-60 that ran cool. The reverse rotation transferred engine torque to the left, or inside wheels, and the car scooted around the turns like it was on rails. The downside was the long path from the carburetor to the valves and acceleration off the turns was a bit slow.

Buddy Shay drove the car at Lakeside Speedway in 1941. There were a few Offys in Denver and they won most of the races but Shay ran well and usually finished in the top half of the field.

Like so much of the "good ole days" of midget racing, the Shay-VanDersahl "Upside-down and Backwards" engine is long gone. Men with the remarkable talents of Buddy Shay and Frank VanDersahl are also gone from today's midget racing. The almighty dollar rules supreme—a shame! ... side-down/

The midget racecar you are referring to was built by Frank Van Dersarl. I originally read about the car in a magazine and a few years later I met Frank and we became friends. We talked about that car and Frank told me that if you could solve your oiling problems with an upside down engine you got an immediate 10% increase in horse power. Makes sense with gravity helping the piston go downhill on the compression stroke. He pointed out that a number of early aircraft engines were upside down.

He told me that the engine "had a really unique sound". The first night at Lakeside Speedway in Denver, Buddy Shay was turning hot laps when the crowd in the grandstands began to flee. They were running out of the grandstands. The unique sound of the engine had set up a harmonic in the metal roof of the grandstands and got them vibrating which then caused them to disgorge many year's accumulation of pigeon guano. The rafters were raining pigeon shit.

Frank was an early flyer and builder of aircraft and from that he figured that running the engine backwards would tend to hold the racecar into the turns on a left hand track.

I have a picture of Frank, ? Mortimer and Buddy Shay in the racecar. Buddy's brother Vic was later killed in this car.

I'm trying to write a book about Frank to garner for him some of the recognition he deserves in the aviation world
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