Twin Dalek

How's this for a capital-W Watzit? The owner describes the beauty as a miniature two cylinder, air-cooled engine with overhead valves, having spark ignition via electrodes through the side of the block and electrodes on top of the pistons. The shaft diameter is 1/4" and it appears to be cast alloy and is certainly hand made. He would like to know if anyone can shed any light on it, and so would we!

From the photos, this engine has more unusual features per square inch than our last half-dozen Watzits. First, look at the valve gear train. On the back of the crankshaft, we have a pair of 1:1 bevel gears, apparently of the involute type. On the cam shaft, our mystery builder has chosen a pair of horological half-circle gears to provide the 2:1 reduction and a right-angle turn at the same time, as used on watch winding stems. The backlash would be terrible, but as the train will (hopefully) be under tension from the valve springs, it *may* all be taken up in one direction, so not matter that much!

The electrodes described by the owner are visible on the left-hand side of the engine. I'm guessing these would be fed by a Model T trembler coil as there is no provision anywhere for points, nor a distributor. The two holes above the electrodes may be the exhaust ports. On the right is what appears to be an inlet manifold, though there is no carburettor of any sort visible. Then, the original Wright Brothers engine dribbled raw fuel onto a hot pan to get petrol vapor to ingest, so absence of a carby does not necessarily mean it ever existed!

The item on top I'm calling an oil tank as there seems to be fine diameter pipes—no larger than the wire straps supporting it—which look like they disappear into the head between each pair of valve stems. The holes around the cylinder jacket would appear to be a very inefficient way of air-cooling the cylinders, but one thing is certain: it's not water cooled.

From the US penny seen in the top photo, this is a tiny engine, with construction akin to watch-making. Perhaps our unknown builder scavenged his odd gear train from an alarm clock and scaled the rest to suit. Joking aside, the castings appear to be very nicely and cleanly done. The stains on the engine are suggestive of a past attempt to make it run, perhaps it even did. If there's anyone alive out there who knows anything about this one, please, PLEASE write to us!

Gatehouse of Fleet

This one we are quietly confident is a "shed job", though a rather nice one. It lives in the UK and from evidence, it must have originated there. The current owner has not made bore/stroke measurements, but from the external dimensions of 83mm front to back and 90mm bottom to top of head, we'd guess the displacement to be 10, or even 15cc. Overall design-wise, it is representitive of the tether car and boat racing engines of the forties and early fifties, featuring a Dooling-like transfer bulge, rear rotary induction, and (presumably) twin ball races. It is sand-cast, rough places, and nicely done where it matters.

There are a few unusual and distinctive features. The use of studs and nylock nuts to attach the front and rear housings and cylinder are unusual, as is the assymetric mounting hole location which has resulted in the front lug segment being wider than the rear (the cut-away lug is unusual too, but not that unique). The head is rather deep and the plug recess seen here could conceal a "button" insert, clamped by the thick head—can't really tell from the photo without pulling the engine apart.

The only markings are the "1954" stamped on the side of the right-hand cylinder flange, and the words "RG Cameron Gatehouse of Fleet" stamped around the front. This does not appear to be associated with the front ball race, nor is the stamping as regular as I'd expect on a ball-race seal (not to mention there's no sign of an outer race cage). Acording to Wikipedia, the "Gatehouse of Fleet" is a town in Dumfries and Galloway, Scotland, which has existed since the mid-18th century, although the area has been inhabited since much earlier. So it's likely that the stamping has something to do with the builder. As usual, if you can add anything to the history of this engine, please let us know.

The Innovation Special

These photos were sent in by a reader from Sweden. The engine was obtained from Mr Kurt Lennå, a well known master scale builder, soaring contestant etc, who is also known as an engine builder. What we don't know is whether the engine was built by Kurt, or obtained by him during his extensive travels. Sadly, Kurt is no longer able to answer questions, so we are left with a puzzle.

The engine is incomplete; the disassembled parts seen here are all there is—and perhaps all there ever will be; we'll come to that. First the general info: the engine is a semi-fixed compression, side-port, compression ignition engine. The owner has measured the displacement as "about 2,7cc", although the photo showing the side by side comparison with the ED Bee might suggest a lower capacity unless the bore is enormous.

Now for the "innovative" parts starting with the backplate and its retention. Note the intricate "J" bolt with a pin that engages a detent on the turned backplate casting. This enables the unit to be drawn into the recess turned in the crankcase, presumably compressing a gasket to achieve primary compression. The single screw at the top closes off the attachment, but does not help the asymmetric pressure applied by the J bolt. Presumably this arrangement was chosen to provide the access required to insert the piston and rod as the crankcase casting is what we might term "mono-block" with head fully integral with the cooling fins and all the rest! The liner is most probably pressed or shrunk in after porting. If you look carefully, you'll see a rather rough opening on the right of the last photo. This provides the passage to the transfer ports. The case geometry means there is not a lot of area around this opening to provide a decent seal, especially as we can't use a gasket here.

The mysterious screw below the shaft journal provides a small degree of compression adjustment. The case is slit at the bottom and the shaft bush is bored off-center and fitted with a nicely rounded aluminum ring at the front which allows the bush to be rotated when the screw is loosened, thus unclamping the bush assembly. The movement provided is about 0.4mm. Not a lot, but as this arrangement also alters the timing along with the compression, small is good.

Now the killer. How the designer ever intended to get the rod over the crankpin remains a mystery and perhaps supplies the answer as to why there is no piston and rod! We are not saying it is impossible that at BDC, a thin rod with a loose big-end could not be persuaded to slide back on the wrist pin and tilt a bit, perhaps just enough to get it over the crankpin. Also perhaps not. A strap big end like that used by Dan Calkin on his ELF's would fix the problem and not increase the bulk of the big end. However, the restricted bypass area and the possible loss of primary compression in that area remains and overall we have enough problems to suggest that the designer most likely gave up. This is a pity as he has gone to a lot of trouble on the crankcase pattern and the machining, which from the photos, appears to be of a generally high standard. If he looses points for execution, he makes up by daring to be different.

Somewhere there may be someone who knows something about this engine. We can't guess at the date of manufacture. The fact that the engine is a side-port is no indicator, since given the general arrangement of compression adjustment and backplate, nothing else would work! If you have any information about this highly innovative and problematic design, we'd love to hear from you.

We Should But We Don't

Here's one all of us think we should know, but somehow don't. It's an archetypal sparker from the Golden Age of sparkers, seemingly nicely die case from the photos, with an unusual side mounted front-rotary induction, threaded internally for some obscure reason. If it's original equipment, the pink "LODGE" sparking plug suggests a UK origin. The bypass cover plate looks like an ideal position for an identification mark, but it's bare. The engine is missing the timing conracts and has some small damage to the exhaust stack, but it otherwise quite clean. Let us know if you have any idea what it is.

Cool Exhaust

Here's one we have no clue about—or should that be another one. The photos came from the current owner who suspects Eoropean origin, possibly early 1940 and possibly kit built. Before you say "easy smeasy", it's the one on the left, next to the Movo, which is provided for size and stylistic comparison. Our Watzit is probably around 5cc with a one-piece crankcase (the bulge on the bottom was probably intended as a case drain, or cut-out, but this has not been implemented).

The most obvious feature of the engine are the rear facing exhaust blisters with cooling fins. These are cast integral with the crankcase, so think a moment how you would machine the exhaust passages! My approach would be drill, then use a Woodruff cutter on the inside of the case to connect to the blind passages. Notice too that the cylinder head is aluminum, apparently screwed onto the steel cylinder liner, very reminiscent of the Aeromodeller/Sparey 5cc diesel, right down to the tapered, slotted fins on the head which can only be cut after the head is fitted. Also notice the compression stop, a common feature abandoned by makers in the late 1940's when users started pulling them out like rotten teeth.

Lastly, the rear view shows a stamped number which may mean anything or nothing, but has been applied in a reasonably precise way in relation to alignment. Notice too the close fit achieved on the recessed, screw-in backplate, contrasted by the rather less than precise work on the venturi flange. The photo also shows the heavily tapered and rather thin mounting lugs which have holes in their rear face for some unknown reason.

We don't know what the threads used are, which is a pity as this is a valuable origin clue. The owner says the case shows some file marks, but given that all early diesels were hand-made, this is no clear indication of home built or commercial product. My own feeling is to place the engine in the late 1940's as it is closer, feature-wise, to the Sparey 5cc than it is to a Dyno (especially the needle). As to country of origin, Europe, or just possibly England. So if you have any clues, we'd love to hear from you. In the mean time, love those cool exhausts.

A Big Ozzie Watzit!

David Owen bought this magnificent engine years ago, knowing the man who built it, or more correctly, thinking he knew the man who built it! George Yates was a keen boat modeler who lived near Wollongong until he passed away late last century. George had a small, well-equipped workshop and was keen on steam and IC scale boats, as well as racing a 15cc tether boat at the SSME pond in Ashfield, a Sydney suburb.

This is the (nominally) 15cc glow engine which David remembers George running and assumed him to be the builder, knowing he had the skills and the equipment to so do. The engine was received in pieces, having been through the hands of a previous purchaser. It was dirty and missing one crankcase screw, as well as having one broken ring.

Recently, Dave cleaned it carefully, making no attempt to polish or otherwise enhance its appearance. Nor did he replace the missing screw or broken ring, so the engine now is essentially as it would have been found in George Yates' estate, prior to being subjected to some rough handling. It was fitted with an HSS (Harold Stevenson) or MS (Marden and Stephenson) glowplug, both of which were common in the '50s here in Australia, and popular because they were only 8/6d each, compared to the large, brass-topped KLG plug, which sold for 10/6d.

The engine itself is over-square with a 28.50 mm bore with a 22.50 mm stroke, so the actual capacity is 14.35 cc. It features a sand-cast crankcase and front and rear housings and weighs 727g. The massive venturi is 9/16" bore, with a 7/16" restrictor fitted. The large drum valve is driven by an extension on the crankpin and gives 180° inlet duration. The well-proportioned crankshaft runs in 1/2" diameter ballraces and is unhardened. Front and rear flanges are at least 1/4" thick and are held in place with 2BA cheesehead screws which look as if they might have been liberated from some type of electrical equipment; quite likely as George worked for the local electricity authority.

The high-domed alloy piston is fitted with two cast-iron rings and runs in a cast-iron sleeve with barred-ports around a large portion of the circumference. The superbly proportioned and finished alloy conrod has a bushed big-end with a slit for lubrication. The unbushed little end is drilled for lubrication and runs on a silver-steel wrist-pin with alloy endpads. The carefully contoured, domed head is actually a button, like that fitted to more recent designs, clamped by the finned head. Dave reports that the overall standard of construction is quite high and the engine does have a nice feel, althought it would appear to have had quite a bit of running.

The design is typical of a classic tether-boat engine of the '50s and Dave assumed it was made by George from a casting set of the type commonly available through model engineering clubs in those days.

However, the conrod has the number "2" neatly stamped on the little end. The crankcase has the number "4" stamped on each side of the exhaust duct interior where the faces would have been finished with a 3/8" cutter. This would indicate at least two conrods and at least four crankcases were completed and numbered to relate to individual engines. Why would George number them? As far as known, he only made one example.

So perhaps George didn't make the engine himself. Was it made as one of a small batch by someone else? Possibly a tether-boat enthusiast who was also a member of the very active Sydney Society of Model Engineers? If anyone can shed more light on this interesting engine, please contact us through the eamil address at the foot of this page.