911hillclimber

Not sure if this is going to be a bit boring, but i am sure i will need some advice along the way from you! Having built the Hemmingway Sparey 5cc diesel (still unfinished business until it runs) I thought another trickier engine would be the ticket to a few more sleepless nights. Thus I bought a Hemmingway Aton Minor Mk3 box of materials, the large parts/GA drg and the book written by the designer on how to make it. The book is great. It seems he wrote it just for new-comers like me so I'm following his advice as well as watching the You tube episodes of Paul's Garage Projects. I will be using the Drummond round bed lathe and the Myford compound slide but have just invested in my first precision pillar drill, all fresh and new from China for £15.99. I have a new small capacity 240V piston drill that will fit, so all those case screws on the Atom design should be true. I've treated myself too with a real parting off tool and a small angle plate to help making the slightly awkward crank case. As i type this, the main case has been faced to 1" width and looks good, the bore for the cylinder is next which needs the angle plate on the face plate I have. The crank casting only just went into my 3" 4 jaw chuck and was looking very precarious, but with light cuts it was good. If the regular watchers are thinking, "oh no! not again" let me know and I'll reduce the thread to simply cries for help along the way. I WON'T be offended.

Rich: Yes, assembling the engines, set up and getting them to go. Not always straightforward! The Atom Minor is a Hemmingway kit, so cast case parts and head. Casting is surprisingly good, better than the Sparey kit's casting. Jon: No, the CP slides back, no 'crack' to a decompressed position. When I made the head I used an M6 x 1.00mm pitch thread. The engine uncompressed to engine fully mechanically impacted to the CP is a radial turn of about 100 deg of the screw. Through all this I feel the engine should start to some degree, but there is nothing. I can't touch the engine now for a few days, but will try later again this week and report back, esp if it starts!

To respond to these thoughts (of which I am very grateful): No video of the ;action' but i will try to express them Engine on a stand, 16" prop and a length of broom handle to flick it over to save my old fingers. Fuel is MT1000, sure smells of ether! Prop tight on the crankshaft @ 2 O'Clock and the piston right up to compression, maybe 15 deg BTDC. Sharp flick over compression is the technique. Neat fuel on the ex ports with piston at BDC, rotate to 15 deg BTDC and flick. There is the sharp 'pop' you get from these engines and the prop spins round to 15 deg BTDC and stops. The compression stops the flywheel effect of the prop going over compression again. I repeated this action a 1,000,000 times varying the compression, the prime and the addition of old Easy-Start spray and noting changed except the snap of the pop, no firing nothing at all, 'lifeless' you might say. To piston/cylinder leaking: Prime the engine via the ex ports and rotate the prop to compression slowly. Ease it over tdc and round again. Just on tdc and holding that position small bubbles form just by the ex ports the neat fuel leaks by the piston skirt. Flicking the prop as you would there is none of this bubbling. The action is too quick. I am beginning to think I have over primed this engine and flooding it all though all these attempts; as previously said a few drops only, i was giving it far more than that. A friend I spoke with (an experienced model engineer) had a glow engine in his workshop in pieces. The piston would not pass into the top of the barrel by hand, and the bore has a taper of 4 thou, wider at the base. Possible actions once I get back to the Sparey will be to make another piston with 'interference' fit at the TDC of the bore, probably mild steel as I can finish to size this easier than cast iron. This would be to test this 'tight at the head' theory. As to the Atom Minor: Started to machine the main case today which went really well, quite surprised myself! Not sure there will be too much interest in a build as it shows my low skill set in these matters. I am far more more at home building big tuned 3.2 litre Porsche air cooled engines!!

Thank you Rich. The fuel is the MT stuff, 1000, in a white tin. Must admit to using more than a drop of fuel to exhaust-port prime, but did not drown the engine. Tried a mix of easy start (old can of it) and the fuel, but to no avail. It is on the shelf now, but I'm sure i will re-visit it before long. Started the Atom Minor today and did some good accurate machining too!

These are the engines in my 'collection'. Bought when found cheap or bought with my heart, not head! In order of the pics below: Autojumble find for £5 40 years ago: OS PET from my schooldays: Bought for £70 when on hols via ebay some years ago: My favorite find for £18: My very first ever ebay buy, a delightful CO2 in the model, i have the wing too: And the last one not pictured, but a new PAW 1.5cc still boxed, never run.

The engine on the right I found in a local antiques market for £18. It is a cracker, moves freely too. was going to get it going, but was bothered it would fail and break. I asked on Rome about what is was, but long forgotten now! Im sure the above is right. Ill gather my other engines together to be of more interest.

Should have said the exhaust ports.

Yes, I am disappointed in the lot TBH. I've battle long and hard on many restorations and won despite lots of issues, but have little interest in fight this out. The project was more to do with the old lathe than the engine, but a runner would have been good. A new ultra tight fitting piston would possibly answer your thoughts? There is absolutely no activity in this engine, not a pop or anything suggesting it will fire, just nothing. Must be fundamentally wrong somewhere in what I've made. When the piston is at BDC the piston top is flush with the ports.

I smell of ether... I smell of blood sweat and tears... This engine (if I dare call it that) will not start. both wrists hurt from trying and the wood prop looks like firewood. I have decided to leave it for a while or for ever (preferably) and let it sit on the shelf and remind me that this is a Bad Day. Found a fancy brass engine stand, so this is the final picture:

Yes, good advice. I used this method on a 1949 Terrot French motorcycle 2T petrol I restored a few years ago to good effect, but not a tiny oil burner. The wood prop has started to splinter where I've been using the broom handle to flick it over. The handle has a plastic protective sleeve which is intact! Not sure this is all worth it, but will try harder this weekend. Funny how the distinct smell of the fuel brings back memories from 60 years ago!

I think I will rig up an electric starter using a pistol drill running anti-clockwise and see if fast repeated turning over will get it going. Not even a good dose of Easy Start helped. Another piston sounds boring, but maybe I'll try again. What i don't grasp is that I can take the compression to very near hydraulic lock down to 'zero' and nothing happens, you just loose the 'pop' as the piston goes over centre.

This will make a nice paperweight! It will NOT start no matter what I do or try. Do not feel inclined to keep on trying as I feel there simply is not enough compression to get to the ideal mixture. In the meantime I've bought another design to make on the Drummond. It is a 1933 design spark ignition, 6.3cc and more complex to machine. Tinkering is better than using. The audience has all but dissipated now, so thanks for following the adventure, and a special thanks to those who have guided my progress on my first engine. I won't do a thread on the next engine. 73T 911 Cou

Hope to do the same next week! Just bought another 'kit' off Hemmingway, the Atom Minor Mk3........

Oddly, made the brass ended pin in a jiffy and is a nice snug fit and feels good in the cylinder, so job done. Wonder if the ends will last?

It is the MT fuel now on order. Further delay until I try to start the Sparey.