Enfield with Ruggerini MD151

[henneberg]

Hi,

My first Enfield diesel build was with an Yanmar L100 engine, https://www.dieselbikeforum.com/view ... =31&t=1957 , and it was finished by 90% when I found an 2 cylinder 654 cc 16 HP Ruggerini MD151 engine at a quite well known auction site. You all properly know the "must-have" feeling, so I won the auction
It was in good condition, "just" the piston rings needed to be renewed

Nowadays it is the same engine as Kohler/Lombardini 25LD330-2 and it is a 650 cc version of the 850 cc version Ruggerini MD191/Lombardini 25LD425-2.

Mechanical fuel pump, the tank and exhaust muffler are omitted :)

These engines have the same mountplate shape at the output shaft as the the original Enfield Taurus 6LD325 engine, so it fits nicely to the Taurus inner primary chain case.
That is, no need for an adapter plate between engine and inner primary chain case WHEN using the long Enfield gearbox diesel mainshaft version !

Primary chain, clutch/mainshaft support bearing and sketch of primary chain wheel

The big challenge is always to align the engine to clutch and to achieve adequate "round-the-engine" clearence.

The following pictures show my mounting fixtures between engine and gearbox, engine and downtube, enginehead and frame..

Square tube 38x40 mm 200 mm long fitted to engine. Later welded to the gearboxplate (5.6 mm thick).
The 6 hole engine plate 4 mm thick.

Fixture between gearbox and rear side of engine.
Made of 4mm and 5.6 mm steel plate and square tube, weight 2.5 kg

Frontadapter weight 1.9 kg

Engine head adapter. Connects to the Enfield frame with a rod, 25x115x5 mm piece of steel.
Made of 5 and 6 mm steel plate pieces, weight 0.4 kg.
The leftmost 2 holes are to fit the diesel filter

Engine in frame, ready to test run

[Stuart]

So the MD 151 has the 180 degree crankshaft like the 191? It gives less vibration than a 360 with both pistons going up & down together.

[henneberg]

Hi Stuart,

The diesel pumps fires with 180 degree intervals and no firing the next 540 degree, and so the scheme is repeated every 720 degrees ( each second rotation ).

I hope the MD151 vibrates a little less than the MD191, due to the smaller cylinder volumen, and thus add less stress to the old Enfield frame.

Erik

[Stuart]

They are good engines. Mine sounds great after its warmed up (15miles or so), especially with the Suzuki silencer.

[witworth]

Hi
Im in the process of a similar build..though some way behind. i.e same engine, and bike
Very useful pictures
Wondered whether you could help with a couple of queries
Are you using the existing holes in the Taurus inner chaincase? Theres an angle of c.25 degree offset with these holes so that to use them you either have to raise the engine or tilt it forwards (as in the Centaurus). Is there enough room under the tank to raise the engine enough to keep it vertical?
I wondered what length gearbox mainshaft you are going to use
I worked out that to get the CoG of the engine right you needed an extra 80mm over the standard shaft ie the Ruggini is 80mm wider measured from CoG to the inner face of of the inner chaincase than the original Enfield Bullet
Im also wondering how to mount the engine. There seem to be two approaches. Either to hang it off the gearbox or to weld in a subframe and mount the engine onto it. I would prefer the first, as you have done, but have some concerns about the lateral stiffness of the frame. Ive read some where that the Centaurus had problems with frames cracking?
One last question...are you planning to use gravity feed or put in an electric fuel pump?
Thanks for you help and good luck with the build...look forward to hearing more news!

[henneberg]

Hi,

I am not using the existing holes in Taurus inner chaincase, I have used an approx. 10 mm long piece of M8 thread with a centered tip in one end, to punch a mark for drilling each of the new holes.

I do not tilt the engine, I raised it, there is still sufficient room for the tank.

The gearbox mainshaft is the long version, approx 334 mm in total length, 55 mm longer than the standard Bullet mainshaft.

With the engine in place, the engine gravity center is close to the frame center vertical line. Looking vertically top-down above the frame tube, the line between the two engine heads is aproxx. 10 mm left to the center of the frame.. Hope it makes sense !

I just use gravity fuel feed, it seems to be working fine.

[henneberg]

Good news,

My Enfield build with Ruggerini MD151 runs nicely - now breaking in the engine, so I do not pull above 90 kmh

Compared to my earlier Yanmar L100 build, the MD151 pulls quite better off.

The well known 3-4 gap in the standard Enfield gearbox isnt an issue anymore, revs easily up to 80 kmh in 3rd.

The engine runs pulls ok from 50 kmh in 4th @ 21 teeth gearbox sprocket.

[gilburton]

The Ruggerini engine is a nice fit!
Still no takers for this but the Chinese Ruggerini clone would possibly make a good alternative to the Robin which is now hard to get??
https://www.dieselbikeforum.com/view ... f=5&t=2632


http://www.ebay.co.uk/itm/20Hp-L290-LAU ... 53ed66c4a3

[henneberg]

It will gone be a quite heavy implant of 75 kg, adding more stress on the frame downtube and gearbox mounting,

The Yanmar L100 is 46 kg, The Ruggerini MD151 weights 60 kg.

[Stuart]

Looks good Henneberg - I just posted to our FB page

[witworth]

Hi Erik
I looked at your shots of the bike on youtube..looks and sounds good..wondered about the shot of the speedo...am I going to get more performance than I am expecting? or is it a slightly optimistic speedo? Mildly concerned as I have an identical bit of kit in a box waiting to fit!

[henneberg]

Hi,

The speedo is approx. 12 % optimistic. I am using a 21 teeth gearbox sprocket, which should give approx 108 kmh topspeed, see table below.

The engine doesnt fire optimal at one of the cylinders, so when it is fixed, I presume it will pull to full rev with a 22 teeth gearbox sprocket.

[witworth]

Thanks. Great spreadsheet. That is a useful top speed which is enough to keep up with traffic. Im going to leave the standard 17T sprocket on for now. Lots of steep hills round here so will wait and see how it gets up them before changing any cogs. I saw that you are using a needle roller bearing in the support housing on the Taurus inner chain case. Wondered where that came from? I got one from HP here in the UK which is a phosphor bronze bush.

[henneberg]

I wanted a better clutch support bearing than the HP bush bearing due to the engines 32 Nm torque.

I tried the bush bearing in my Yanmar build, it went hot and the bronze bush crashed the alu bearing housing !

Here is the bearing housing sketch with an oil seal 20x32x7. For now I have added a HP oil seal on the outside of the chain case !.

The 4 holes need to be drilled for the Allen screws to fit the Taurus inner chain case bush bearing mounting threads.

Link to roller bearing data: http://www.consbrgs.com/details/224/224_1_18.html

[witworth]

Thanks for the warning about the bush and the drawing of your design. The bush is certainly very under-engineered in comparison to the shaft support on Stuarts Ruggerfield. Have attached picture of current state of build..still much to do before its on the road, but the engine fits (just ) without any frame surgery.

[henneberg]

Looks nice, just about the stage of my build 3 months ago.

There are quite a number of steps to get it running, but this engine just adds the adequate fun running a diesel Enfield.

The ultimate method of manufactoring the gearbox-engine mount would be with a CAD drawing, and a piece of aluminium in a CNC machine, which will be more precise compared to welding steel plates.

[old clunker]

Great Job Erik! The bike looks and sounds good.

How are the vibration levels with your Ruggerini engine at low and high speeds?

Let us know how you are getting on, when the engine is fully run in.

[henneberg]

Hi,

A few updates on the build:

A KN SU airfilter is replacing the industrial filter, using a piece a steel plate "interface" the inlet to the SU filter:

Slimlined the Ruggerini flywheel - got the weight down from 7.1 kg to approx. 5.1 kg.:

Last major change will be to have two, separate exhausts, one for each cylinder,