help with engine selection

[witworth]

Hi..Im planning the usual Enfield diesel conversion and looking a suitable engine, preferably with more grunt than the Yanmar...Ive looked at the Ruggerini md191/151 outline drawings, trying to work out whether it fits into the Bullet frame. Ive looked over the forum for clues but without success. Is the original Ruggerfield a Bullet frame or from another Enfield model? Does the Ruggerini fit into the Bullet frame and if so how? Looks like there is conflict with oil filter, oil filler, and pipe work between engine and gearbox. Any help would be gratefully received. Great site by the way. Very useful technical info. Rgds ww

[old clunker]

Welcome to the DieselBike forum - as for engine choice, it depends on how much you've got to spend, and how heavy you want the bike to end up!

I've got no personal experience with the Ruggerini md191/151 engine, but there may be someone around that can assist. You have to watch out that the engine is not too heavy for the frame, which is not that 'sophisticated' construction wise by today's standards!

The Rotek 460cc single rated at 13HP? seems a good compromise for the Enfield frame, otherwise a few have been successful in 'slotting in' a Kubota 500cc twin, though being water cooled, it needs a lot more plumbing work.
I've even seen an Enfield running an 800cc Punsun V twin, though I don't know how long the frame would last with that relatively heavy engine?

The Enfield is a popular choice, as it's quite simple to work on, and you essentially get a 'free' gearbox, once you ditch the old petrol engine, and spare parts are readily available.
The main thing going for the Yanmar/Yanclone engines, is that spare parts are readily available, and are fairly reasonably priced which helps.

Good luck with your project, whatever engine you decide to fit.

[Stuart]

The Ruggerfield is based on a Bullet but I'm pretty sure not all the parts came from the same model bike. For instance, a replacement gearbox shaft needed to be from an Interceptor.
MD191 is a good engine used on several builds but it is wide & a carrier box had to be built to hold the extended clutch. Engine also has a 180 degree crank for a lot less vibration.
I don't recall any probs with oil filter but filling it is tight. Also throttle assy is had to get at.
Let me know if you want any specif pictures & I'll post them.

[witworth]

Thanks for the advice ( and thanks for moving the topic to a more apt location ). I remembered that the Centaurus used the Ruggerini and had a look at some photos. I guess one of the reasons that the engine is angled forwards in that bike is to give better access to the oil filler.

In terms of the width, do you know whether the replacement inner gearbox case (with carrier) and shaft as used by Sommer (and Priceparts?) provide sufficient offset to place the engine (MD191) reasonably centrally in the frame? Is the inner chain case on the Ruggerfield mounted directly to the engine casing or does it use some form of adapter ring (as used by Altman/Priceparts )?

What would be very handy is a photo showing how on the Ruggerfield the frame members coming under the engine connect to the gearbox/rear frame
The method used by Altman for the Yanmar clone i.e a plate attached the forward face of the gearbox casing looks like is uses up valuable space between the engine and gearbox

Im sorry these probably appear to be very basic questions which cover old ground but I guess we all have to start somewhere. Help much appreciated.

[Stuart]

"Thanks for the advice (& thanks for moving the topic to a more apt location )."

I've not moved it yet - but maybe someone else did? Expect it to go to the Engine section...

"I remembered that the Centaurus used the Ruggerini and had a look at some photos. I guess one of the reasons that the engine is angled forwards in that bike is to give better access to the oil filler."

I might have been to limit the vibes on the Centaurus. I'm told it has a 360 degree crank & the vibes from that can crack the frame. The MD191 has a 180 - much better!

"In terms of the width, do you know whether the replacement inner gearbox case (with carrier) and shaft as used by Sommer (and Priceparts?) provide sufficient offset to place the engine (MD191) reasonably centrally in the frame?"

It's pretty central but is offset a little if memory serves - pics to follow.

"Is the inner chain case on the Ruggerfield mounted directly to the engine casing or does it use some form of adapter ring (as used by Altman/Priceparts )?"

It's mounted to the engine. I had to fit countersunk screws to fix it after I built & fitted the dry race clutch because the belt Philly wheels were bigger than the chain sprockets. I fitted a dry clutch because A: the original slipped no matter what I did & B it was geared too low with a top speed of 55mph. It's now closer to 70 at a push & flat out.

"What would be very handy is a photo showing how on the Ruggerfield the frame members coming under the engine connect to the gearbox/rear frame."

The frame joins the engine at the front and does not go under the bike.

"The method used by Altman for the Yanmar clone i.e a plate attached the forward face of the gearbox casing looks like it uses up valuable space between the engine and gearbox..."

It's tight back there & the plates are used on the Ruggerfield.

"Im sorry these probably appear to be very basic questions which cover old ground but I guess we all have to start somewhere. Help much appreciated."

Have you seen the threads detailing clutch & gearbox repairs on the bike? Some shots there...
More to come later..

[Stuart]

Ok, as promised, here are some shots to give you some idea of the Ruggerfield's makeup.

First up a central shot showing position of engine relative to its mounting.

Shots of the front mounting...

About 4.5" to the edge of the engine from the bracket.

...and the plate that bolts to the engine is about 1/2" thick.

[Stuart]

...and a few more

Underside of the lower plate that forms the base part for the above the carrier box which comprised of two bearings.

Top view looking down on carrier box - it's about 4.5" width...

And it's (forgive the mixed measurements!) 65mm deep..

Here you see the back plate with chain entrance & exit. After taking this lot apart it struck me as being very well if not a little, over engineered - but I'm not complaining!

A shot of the head steady. Very solid!

And the unihead ganged up intake & exhaust ports...

[Stuart]

Here's a few shots from the other thread that show the bearing carrier box.

And where it fits...

[Stuart]

And more shots from way back showing the whole plate... (pls excuse shots loading last first - it just happens that way.)

[Stuart]

I came across this by accident earlier - sketch detailing the shaft that extends out the back of the clutch & sits in the carrier bearings. Don't take any measurements as gospel but it went together ok & still goes

[witworth]

Many thanks Stuart for answering the queries and all the photos. Its going to take me while to digest all this info. The bearing carrier block is a substantial bit of kit! Regards ww