Project 100 (custom enclosed Honda C90 targets 100 mph vmax and 100 km/L FE)

[PeterS]

What we need are small light air cooled diesels .... if you want good fuel consumption numbers .A diesel is 33% efficient , a gas engine is around 22% .A 50% gain right there .

[Frank Lee]

Yeah, I think Harbor Freight sold little one lunger diesels too once upon a time? Not now. :/

[TXwaterdog]

NH northern tools has quite a good selection for New Diesel engines:

Diesel Engines | Engines | Northern Tool + Equipment

I'd go for the Kohler Diesel Engine — 401cc, 1in. x 3.62in. Shaft, Model#KD400

It goes for Only $1,899.99

KEY SPECS
Displacement (cc) 401
HP 9.8
Torque (ft./lbs.) 16.6
Engine Type
4 Stroke single cylinder
Shaft Dimensions Diameter x L (in.)
1 x 3.62
Shaft Keyway (in.) 3/4
Manufacturer Warranty
3 year limited warranty
Ship Weight 110.0 lbs
Item#60277




It would jack the project price up a bit but it's really what you're looking for.

[Frank Lee]

See- "only" LOL two grand and you don't even get 10 hp... vs I can buy a complete overhaul kit for a 350 Chevrolet for $168. Hmmm, what's wrong with this picture?

[CFECO]

Supply and demand. There are many small Kubota engines for under $1000 on Ebay. If one looked enough, you could probably find a used, Polaris or other brand diesel atv to get the engine out of, and it would have the transmission with reverse. Perfect for a small light High MPG vehicle.

[Frank Lee]

"Supply and demand"?!? Isn't that where when something is in greater demand and tighter supply the price goes up? So there's a huge demand that is squeezing the supply of one-lunger diesels and there's low demand and excess inventory of 350s?

[dcb]

sort-of, the 350 has been around so long that 3rd party suppliers have long had the necessary dimensions and tooling to crank out parts. There was a large supply of small blocks at one point, and the parts market is out of phase with that and just making residuals.

Well it sounded good anyway, might be crap too

[user removed]

Originally Posted by SimonSellsAustin

NH northern tools has quite a good selection for New Diesel engines:

Diesel Engines | Engines | Northern Tool + Equipment

I'd go for the Kohler Diesel Engine — 401cc, 1in. x 3.62in. Shaft, Model#KD400

It goes for Only $1,899.99

KEY SPECS
Displacement (cc) 401
HP 9.8
Torque (ft./lbs.) 16.6
Engine Type
4 Stroke single cylinder
Shaft Dimensions Diameter x L (in.)
1 x 3.62
Shaft Keyway (in.) 3/4
Manufacturer Warranty
3 year limited warranty
Ship Weight 110.0 lbs
Item#60277




It would jack the project price up a bit but it's really what you're looking for.

You wil need some serious strength to pull start a 9.8 HP diesel engine.

regards
Mech

[CFECO]

Millions of small block Chevy engines produced in over half a century plus the hotrod market = low cost due to large demand and supply. Small diesel engines have a relatively small demand here, plus the enormous cost for new design and tooling for production all add up to high cost. Due to EPA regulations, even small off highway engines have to meet stringent emission standards which also increases cost.

[beatr911]

Back to the issue of cooling which will need to be addressed before meltdown.

With experience gained from using grill blocks and the info posted by someone that with a fully ducted (in to the radiator and out) cooling system, the area that is needed is about 4 square inches per 25 horsepower. Now this is for a water cooled engine mind you, that is moving.

So, to extrapolate to fully duct an air cooled engine, the air intake needs to be in the high pressure zone in the front and the air exit needs to be in the low pressure zone in the rear. The air needs to be directed to blow directly on the engine, stay close to the engine and exit in an efficient manner. I would be hesitant to allow too much room for the air to swirl around the engine, the object is to heat the air and pass it out the back end as quickly as possible to keep the engine from overheating.

I didn't see Allans CRF230 up close, but as near as I could tell there was no ducting specific to sending air past the engine. Using the natural pressure relationships afforded by vehicle movement can produce pretty good cooling possibilities if done well. Brittens water cooled v-twin used a very small radiator behind the engine immediately in front of the low pressure area in front of the rear tire in the fender area. Filling in this low pressure area with hot air reduced drag, not to mention slightly reduced frontal area. The man was simply brilliant.

For the ~12hp needed, I'd at least double the 4sq in/25hp rule and use 4-6 sq inches and duct it closely around the engine. The increase in area isn't much to reduce temperatures.

The real advantages of water cooling are more even heat distribution within the engine, faster heat rejection from hot spots, allowing a higher state of tune (more output), being able to put the cooling radiator where you want it, the additional heat sink mass of the cooling system while stopped, and the ability to have a fan to cool the engine while stopped. There are many advantages to water cooling, but I don't like the toxicity of antifreeze and the additional failure modes of the cooling system. A larger air cooled motor working less hard can last a good long time if properly cooled.