Di(iesel)Va(lentines)

This DIVA 0.098 cc diesel was manufactured in 1982 and was the world smallest diesel engine of its time. This miniature diesel laid out the platform to make Valentine's engines world famous.

DIVA is short for Diesel Valentine.



There is more to follow!

ian1954 wrote:This is the engine that started Ronald's venture into the world of minature diesels. When I say "the engine" -  This one is the prototype - the very first Mk I Diva.




Bore 5.0 mm
Stroke 5.0 mm
Rpm 18,000 rpm
Total combustion 0.098 ccm
Weight 15 gram
Intake Disc Valve

Holy Mackerel... that's a .197" Bore/Stroke!!! Being a diesel.. I'll bet it could swing 4+ inch diameter props? What prop size (D/P) was the 18K achieved with?

3 x 1 is good for this size.

That's amazing Ian, Thanks for posting pics/info!!!

Now we move on by adding the MkII and the MkIII

These were made in 1985. Again, they are the prototypes.

The second DIVA of which only 10 were Manufactured. The main difference between the DIVA Mk I and Mk II, next to the different cylinder form, was the carburetor mounted in the back plate.

Bore                         5.0 mm
Stroke                      5.0 mm
Rpm                       18,300 rpm
Total combustion     0.098 ccm
Weight                    15 gram
Intake                     Disc Valve



Ronald's constant quest for refinement produced the Mk III. A different carburettor design produced a rpm increase of 4,500. Only 10 MkIIIs were produced.


Bore                         5.0 mm
Stroke                      5.0 mm
Rpm                       22,800 rpm
Total combustion     0.098 ccm
Weight                    15 gram
Intake                     Disc Valve

The crankcases are dated

Is the Diva Mk II the engine with less cooling fins on the cylinder?.. or is it the one with the noticeably different (longer-black) venturi? I ask, because all 3 engines pictured are stamped "DIVA I" on their cases.

Left to right, Mk1 MkII Mk III.

Diva .1 (.098 rounded up)

Now for more.

The 1987 Diva Twin MkI opposed twin. This engine is the first opposed twin constructed by Ronald and one of the smallest multi cylinder engines of its time.

When we talk on this site of rare engines - you don't get mucher rarer than this. This is the one and only prototype.

This engine has a one piece crank shaft and divided connecting rods. The connecting rods are held with two miniature screws.

Ronald is a perfectionist. Most of us who build engines make no provision for repairs to multi cylinder engines - particularly flat twins. With an engine of this size - it is common to find that the leading cylinder conrod is "permanently" in postion - the crankshaft has been built around it - silver soldered or  "press fits" which are also difficult to achieve and dismantle in such minature connections.

To build a conrod that is split in two and then screwed together (imagine the size of the screws!) is masterpiece in miniature. This does, however, enable repair and parts replacement.

Now here we have the DIVA 0.1 Mk V of which only 5 were Manufactured. The main difference between the Previous DIVA's is that this one is dual ball bearings. All previous DIVA's had a single bearing.

It is pictured with the the DIVA 0.1 Mk VI of which only 5 were Manufactured. The main difference between the Previous DIVA's and this one is, the steel cylinder and the red anodized cylinder head. The cylinder head was held down with 4 miniature screws. Again this has dual bearings.




Mk V
Bore 5.0 mm
Stroke 5.0 mm
Rpm 22,800 rpm
Total combustion 0.098 ccm
Weight 15 gram
Intake Disc Valve

Mk VI
Bore 5.0 mm
Stroke 5.0 mm
Rpm 24,600 rpm
Total combustion 0.098 ccm
Weight 15 gram
Intake Disc Valve

Now here is another one off prototype DiVa.

The main difference between the other DIVA's is the crank case design. The cylinder head and back plate are mounted with miniature screws.

The crankcase has also been sand blasted. This gives a "cast" look to a machined crankcase and forms a grey colour as it ages.



Bore 5.0 mm
Stroke 5.0 mm
Rpm 23,200 rpm
Total combustion 0.098 ccm
Weight 14 gram
Intake Disc Valve

More recently and currently in production is the FR DiVa - the Mk VIII.

Here are two of them - they, like all Ronald's engines, have a uniqueness about them. They are hand produced and there is no automated process.

Each engine is therefore individually built.

The two shown here are different - one has a black tommy bar and needle - the other is denoted as "silver".

Once more - masterpieces in miniature - "Men's Jewellry!"

Here are the DiVas together. There is a RoVa amongst them - my mistake - but it took me a long time to set this up.

Spot the RoVa!



Every DiVa is different and this is just a snapshot of miniature engineering that surpasses any of my skills. Perfection and constant improvement. Refinement of techniques as time progresses.

I chose DiVas for this topic because they span Ron's 32 years of miniature diesel development.

I am fortunate to have the engine that started it and am able to show a montage of progression with one group of engines.