The Stovebolt Site Forums The Shop Area Engine Shop 216cid Engine Horsepower - What is it?

The ID plate on the door sill of Ol' Roy says, "85hp at 3300rpm"

I assume that is the HP rating of an engine on a stand with no load or accessories. Is that correct?

Does anyone know the actual usable horsepower "to the wheel" on a 216, 3pd, 4.11:1?

Just curious. I think about these things while I'm putting down Ga 400 at 60mph while being passed by everyone else at 80+mph.

That's probably flywheel HP under full throttle- - -full load at the rated RPM, without accessories such as the water pump, generator or other bolt-on devices. Pick an RPM, start applying load and increasing the throttle opening, until any further load drops the Revs. Measure the torque output, and calculate HP, taking into account ambient air temperature, altitude, barometric pressure, and relative humidity. I've run many hundreds of dyno tests that way.
Jerry

If you had to make a ballpark guess, what would you think the hp at the wheel is? It's obviously going to be less than the 85hp printed on the ID tag.

Probably less than 70- - - -depending on wind drag, rolling resistance, power loss through the fan, the trans and rear end, and a few other factors. Thermal loss through the cooling system also drops the flywheel HP, but that's possibly taken into account in the flywheel HP rating. Over-cooling a high performance engine with aluminum heads and a big, efficient radiator actually robs available HP from the rear wheels.
Jerry

Heat = energy

Wind drag for sure won't have any affect on the wheel output when measuring rear wheel HP on a dyno. But it will affect the load going down the road.

For a typical IC engine, you get 1/3 of the input (fuel heating value) out the flywheel, 1/3 loss thru the cooling system, and 1/3 loss thru the exhaust.

FWIW, here's the certified HP curve for a 216 engine (from the 1951 Vehicle Info Kit - the 1950 didn't include that chart.) It notes what's not included (fan, generator, etc.)

Probably need to knock off 10% for losses thru the gear train (transmission and rear axle). So I'd say you get about 75 HP at the rear wheels under optimum conditions.

Good point on exhaust losses- - - -that's why a turbo boosts power- - - -it salvages some of that exhaust heat and puts it back to work compressing the intake mixture.
Jerry

My 1-ton lists the net horsepower on the door post as 78 at 3300 RPM IIRC. These were developed in the 20s and 30 and by the 261 days they claimed to coax 150 hp at 4000 RPM for 1962. Olds was the first to use turbocharging on the 215 ci aluminum V8. I think that was about '63. They advertised 215 hp. There was a Buick version of that engine too, perhaps without the turbo. Eventually the design was sold to Rover and appeared in their 3500 model.

At the same time Chev was developing its inline 6s, Curtis Wright along with Pratt & Whitney were developing the multi row radial aircraft engines in the 20s and 30s.The last of the reciprocating aircraft engines on airliners had a scheme to return exhaust energy back to the prop. Curtis Wright built these supercharged 3350 cu in, 18 cylinder monsters with a sort of reverse trubocharger in the exhaust system. Pratt and Whitney built what were known as Corncobs, four cylinders deep and 7 around at 4460 cu in. When you look at the plumbing you can see why airlines went to jet engines. There is one at the Museum of Flight in Seattle.

The radial engines I had any experience with 50 odd years ago were Prat & Whitney R1830s. They were a supercharged 14 cylinder radial, ubiquitous on assorted aircraft used in Viet Nam, DC3s, C47s and many others. They leaked enough oil to pose an occasional fire hazard. The corncobs were even worse, notorious for that. At least a 216 leaks out the bottom rather than starting fires.

Stovebolts were produced concurrently with the radial aircraft engines. By '57 Boeing had the 707 jet in production. And by 63 GM had a new L6, the 230/250/292. GM was a little slow on the uptake perhaps but then a Stovebolt was a good deal more reliable than the radial piston engines pushed to the technological limits in their final years.

Dad flew B-17s with the single row 9 cylinder Wright Cyclone radial- - - -1200 HP at max turbo boost, I believe. He called them "Wright Oil Slingers", but they could take lots of battle damage and keep on running.

One of his mechanics during the 1950s worked on B-29s in the Pacific with a way underpowered, very sophisticated radial- - - -he said very few of them returned form Japan with all the engines running, and even fewer made another mission without changing at least one engine.

https://airandspace.si.edu/collection-objects/wright-cyclone-gr-3350-radial-engine/nasm_A19670013000

Jerry