Lightest production diesel... OMG this is small!!

[Blunt Eversmoke]

If what they claim here is true, then we have a new champion for diesel minibikes, small scooters and the like. 16 kilos for 3 HP is a new dimension of small in the stationary diesel world. And then imagine supercharging it...

EDIT: Watercooled version also available

[alexanderfoti]

It would need to be seriously beefed up to be able to make 10 bhp which would make it usefull! 3hp would really be limiting I think.

[gilburton]

already covered in a previous post "smallest lightest engine"
http://www.ebay.co.uk/itm/168F-3Hp-RECO ... 53eb62252d

[tappy]

16Kg per 3hp is the same as 160Kg per 30hp, so it terms of power to weight it's no better than anything else out there.
Yes it's small, yes it's light, but so's a push-bike.

[gilburton]

I was thinking along these lines but a cycle wouldn't be legal with an engine fitted. How about an older bicycle style moped that already has a reg. document? Or a more modern scooter with the engine fitted under the seat utilising the scooter cvt??
With that tank off the engine would be quite compact. Most older mopeds were only 1 1/2 - 2 hp anyway!
Oh by the way the cylinder would appear to be at the rear if the rotation is c/c as we know is normal.

[Blunt Eversmoke]

I was thinking along these lines but a cycle wouldn't be legal with an engine fitted. How about an older bicycle style moped that already has a reg. document? Or a more modern scooter with the engine fitted under the seat utilising the scooter cvt??
With that tank off the engine would be quite compact. Most older mopeds were only 1 1/2 - 2 hp anyway!
Oh by the way the cylinder would appear to be at the rear if the rotation is c/c as we know is normal.

Exactly, small engine for small applications. Again, lower the geometric compression, fit an overdriven supercharger and you can easily double the HP without putting too much of a strain on the little critter.

[gilburton]

According to the ebay ad they've got 6 left. Who's going to be the first one to try it???

[alexanderfoti]

According to the ebay ad they've got 6 left. Who's going to be the first one to try it???

Find me a cheap supercharger and im in!

[Blunt Eversmoke]

According to the ebay ad they've got 6 left. Who's going to be the first one to try it???

Find me a cheap supercharger and im in!

Smog pump, anyone? To be had in various makes (i.e., directly driven or electrically driven, with built-in motor), costs as low as 30 Euros on Site-Whose-Name-Not-Be-Mentioned. Probably even cheaper stateside.

[alexanderfoti]

Interesting!

This merc one has an electrical clutch! Switchable for fuel economy maybe! (hmmmm)

http://www.ebay.co.uk/itm/1994-Mercedes ... 1c30f43f48

[alexanderfoti]

My eye is being kept on it! I have no money at the moment It would be good to include this in my next build.

I Assume the easiest way to decrease the compression would be to installed a thicker head gasket?

[Blunt Eversmoke]

My eye is being kept on it! I have no money at the moment It would be good to include this in my next build.

I Assume the easiest way to decrease the compression would be to installed a thicker head gasket?

Yup. ONE thicker gasket. Just not multiple ones, that barely functions with gassers - and in a diesel it would be a catastrophe waiting to happen. Then there is the possibility to somewhat retard the injection, that would decrease the CR in the moment of injection, but costs some effective displacement (not sure how much) and increases, I believe, the side load on the piston head and thus the wear of cylinder and rings so no one does it AFAIK.

[alexanderfoti]

My eye is being kept on it! I have no money at the moment It would be good to include this in my next build.

I Assume the easiest way to decrease the compression would be to installed a thicker head gasket?

Yup. ONE thicker gasket. Just not multiple ones, that barely functions with gassers - and in a diesel it would be a catastrophe waiting to happen. Then there is the possibility to somewhat retard the injection, that would decrease the CR in the moment of injection, but costs some effective displacement (not sure how much) and increases, I believe, the side load on the piston head and thus the wear of cylinder and rings so no one does it AFAIK.

Aha right I see what you mean.

Now I need to find somwhere to make me a thicker gasket. The original one is stamped metal isnt it?

[Blunt Eversmoke]

Now I need to find somwhere to make me a thicker gasket. The original one is stamped metal isnt it?

Yes, usually. Oh, another possibility: Keeping the original head gasket and installing a decompression plate between that and the head, using some non-setting high-temperature sealant. Described here for gassers, but might just work on a diesel as well - talk to a specialist on what to make one from and what sealant to use.

EDIT: Oh, and depending on how far the piston skirt protrudes into the crank case at BDC and how long the head studs are, one might try installing a decompression plate between cylinder and crankcase - dunno if it is doable at all, if yes, would make things that much easier.

EDIT once more: If you are planning on going all the way and drastically lowering the static compression in order to really supercharge the engine, you don't need to switch the supercharger off, ever - it will have difficulties starting and idling (and I strongly doubt you are planning to mount a turbo on THAT engine).

Another thing: Since this is a pushrod engine, you must see that the valves still open properly after you have lessened the CR, the head sitting farther away from the block.

[bhtooefr]

It's a dieselized clone of the Honda GX200.

http://www.youtube.com/watch?v=VbcxMFsvUUE mentions that there's some major quality issues.

[Blunt Eversmoke]

It's a dieselized clone of the Honda GX200.

http://www.youtube.com/watch?v=VbcxMFsvUUE mentions that there's some major quality issues.

I have some other data on it from one of the Chinese makers. Is 300 grams per KW even possible? Is it because the engine is so small (others with same displacement get better figures) or because they forgot to change the data and left that of the gasser prototype? If the former, it would be pretty much self-defeating...

[tappy]

300 grammes per kilowatt? At 3hp, it's 16Kg / 3*0.745 = 16000 grammes / 2.235KW = 7160g/KW

[Blunt Eversmoke]

300 grammes per kilowatt? At 3hp, it's 16Kg / 3*0.745 = 16000 grammes / 2.235KW = 7160g/KW

I don't mean specific weight (which, while nothing to brag about, is still quite OK as far as small-power diesels go); it's the low absolute weight that makes this engine interesting, anyway.

No, what I mean is specific consumption which would be higher than that of some gassers of same power if it really were 300 grammes per KWxH - and make it self-defeating.

May very well be a consequence of making an engine of such a small displacement a swirl chamber one - throttle losses, heat losses, higher friction due to higher necessary compression are all proportionally much greater than for a engine of greater displacement.

On direct-injecting engines of same displacement, figures around 250 grammes per KWxH are possible - some comparably-sized gassers do that as well, but since a scooter, being a town vehicle, spends much more time standing at traffic lights and kreeping forward at part-load than a motorcycle, a diesel would still be more frugal. These are some ten kilos heavier, though.