classic motorcycle forum
Motorcycle Discussions => Identify these bikes! => Topic started by: Albion EJ on May 04, 2025, 05:35:03 PM
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Who can help me identifying this engine?
Looks like it is from the thirties.
Stroke is roughly 62mm.
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The Mk VIII-C was the little Villiers that ran from the 1920s until after the war, 55x62 I think. This looks pretty close, but I'm far from expert - not sure about the numbers on the crankcase. There's not another number on the flange under the cylinder, just above the drive sprocket?
Leon
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Unfortunately there isn’t
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I can see the engine numbers stamped across the crankcase halves in one of the photos. This makes it a postwar production. Villiers changed how they identified and numbered their engines in the immediate postwar years.
It’s built to Mark VIC (6C) specifications that had a much smaller carburettor than the later Mk VIIIC and has the reversed inlet manifold of the later industrialised versions. Excellent for the lawnmowers it was built for but not a motorcycle engine and not viable for motorcycle use.
Finally, most postwar Villiers motorcycle engines can be identified as to year of manufacture, what bike it was fitted to and so on but to my knowledge no one has done this with their industrial engines. Perhaps the Lawnmower Club knows more.
Not exciting news I know but these old lawnmower versions turn up with great regularity as old lawnmowers lead very gentle lives compared to their motorcycle brothers.
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Soooo many engines!
Sorting out info on the various Elliott (Adelaide) and Waratah (Sydney) bikes from the mid 1920s - mostly the 147/148cc models in the mid-late 1920s - has left me with many questions!
Both Elliott and Waratah used the little Villiers in Sun "miniature" cucyel parts (the extremely light set, with no rail under the tank) from the beginning of 1923 for Elliott and mid-1924 for Waratah. When they stopped is another matter - maybe 1928-29.
The weird thing is that the engines could be Mk VI-C (H prefix), Mk VII-C (L) or Mk VIII-C (W). We know about when they started (1922 for VI-C, 1923 for VII-C, 1924 for VIII-C), and we know that the VIII-C ran on through the 1930s, but what of the VI-C and VII-C?
I've seen an Elliott that looks pretty original with an engine number H24xxx (very large number for a VI-C) with "1924" stamped after it. It looks like this engine was maybe built in 1924, or if not built into a bike in 1924, by which time the VII-C had come and gone and the VIII-C was available.
I wonder did Elliott buy "old style" VI-C engines in 1924, or were they just left-overs of a 1922 batch?
Ditto for VIII-C engines with high numbers like L10xxx, built into bikes that seem to be 1925 or later.
I guess we'll never know for sure, but I'm pretty sure that dating a bike to 1922-3 because it has a VI-C, or 1923-4 because it has a VII-C is a bad idea! Looks like Australian manufacturers (at least) were using these engines in their bikes well after the VIII-C was available.
Cheers
Leon
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Well we know Villiers made both the Mark VI-C and VIII-C for years after they stopped putting them in bikes. The VI-C in particular hung around for decades even if the VIII-C seemed to fizzle out in the mid-30’s. On the other hand I have yet to see the middle one, the VII-C in anything. It seems to be neither fish nor fowl.
I agree with your suspicion of high engine numbers and I’ve never seen a Villiers engine with a year stamp. I believe that to be a later addition. I can broadly date the later Mark XII-C engines from the number, the Victorian engine numbers and date of first registration records are a great help here but they’re not much help with the earlier VI-C.
Given the brief time it was used in bikes and the long years it was made for industrial purposes you can more or less bet that 99% of any Mk VI-C you find are of industrial background, mainly lawnmowers. My major frustration with this is the users refusal to accept they have a low power lawnmower engine, not a bike engine. It rarely goes down well.
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Hello, thanks for all very interesting information on Villiers engines.
I do have a bike with a Mk XII-C with the number GY 7019.
Will you be able to date this engine?
It has an aluminium flywheel installed where I have seen others having a brass one.
Potentially this change over can be dated as well.
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Can we see a pic of this aluminium flywheel ?
Now I'm no Villiers 'expert', but never seen nor heard of that. ?
They did have a variety of aluminium covers ..
Edit. Ah, does it have sorta fan blades on it ?
Now that I might have seen.
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The first registrations I have around the GY 7000 mark date around the first half of 1936. Can’t get much closer than that. As I wrote earlier I can only broadly date when an engine was produced from registration dates. The registration dates are surprisingly varied, there can be a several month difference between consecutive engine numbers. It is very broad brush. Not that it matters that much as Villiers didn’t make annual model changes and the actual date of manufacture is irrelevant for maintenance and repair purposes.
As for the aluminium flywheel magnetoes yes, Villiers made them alongside the brass variety. Again, it’s not really relevant detail for maintenance or repair so I take little notice. Of far more interest are the paired numbers on flywheel and backplate to ensure you have a factory pair. Mix’n’match can cause problems here.
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is there a picture anywhere of these aluminium flywheels.
Are they lighter than the brass ones ?
Do we know why they came about ...
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Villiers made no distinction between any of the metals used in their flywheel magneto’s. What sort of aluminium alloy it is I have no idea. It certainly made no difference to performance. Personally I suspect them to be more of a zinc/aluminium alloy rather than straight aluminium. Although I’ve never weighed one they don’t feel any lighter. I suspect Villiers were just after a cheaper non-magnetic material for their flywheels and eventually concluded that it was simpler and easier to continue with brass. There’s certainly no logic to fitting a lightweight flywheel to a basic “cooking” model XII-C is there.
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Brass would have been considerably dearer than other alloys when demand was high due to rearmament.
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Thanks all!
I already noticed these paired numbers.
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The Mk XII-C & XV-C engines show a lot of potential but suffer a major handicap. There was never an alternative alloy piston for them. To repeat myself yet again, replacing the original cast iron piston with an alloy version transforms these basic Villiers engines. The alloy 25C piston drops straight into the VIII-C, the 196 Super Sport into the 1E & 2E plus several aftermarket piston firms made an alloy version for the original 175 Sport but there is nothing for the XII-C/XV-C. (The XV-C is the single exhaust port version of the XII-C).
The XII-C has the best breathing of all the pre-war C series. It sports the MW carburettor, the same size as used on the earlier 175’s and the 196’s of its time and Villiers made an appropriate exhaust for it but the times were against it. Two-strokes were looked down upon, fashion decreed a Brooklands flavoured exhaust system and four -strokes were de rigueur. No one was interested in them.
Nowadays we see the potential for a tongue-in-cheek fun little bike but it’s too late for riders with average finances. Financing small batch piston manufacture is a bit beyond us. Pity about that. So close yet so far.
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Would you be able to date this engine as well?
I do have a used cast iron piston at 54mm without rings which is for sale.
Please drop me a message including an offer.
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I'm no expert, but I think the XII-C was introduced in about 1931, and this one might be c1933? No doubt 33d6 can be more authoritative. As i mentioned above, start dates are useful, but it's more interesting to know for how long a particular style of engine was built and used... Always interesting to see an engine like this in its original bike, so that the bike dates the engine rather than vice-versa.
Leon
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Can’t help with the second Mk XII-C engine. My information is based on records of unique Australian motorcycles, not all motorcycle makes. In general most of these minor makes started to appear here in the mid thirties and quickly disappeared when war was declared. None survived WWII. Numbers start around the 6500 and end around 11000 in 1940.
Calculating the Villiers engine approximate year of production from these records was a serendipitous by product of other efforts. It was not my intention nor as I keep saying, does it serve any practical purpose.
As far as your engine stands it is what in my apprenticeship days we called a ‘short’ engine. Not a complete unit and would be used as an exchange, refitting all the essential fuel, ignition and drive components already present from the receiving machine. On its own it is only one sub assembly of a Villiers power unit.
Curiously, the Mk XII-C cast iron piston is well catered for. F W Thornton of Shrewsbury list all sizes and oversizes on their website. It’s only the favoured alloy versions that are hard to find. It seems I’m not the only one to choose alloy pistons over cast iron. Its not a genius decision.
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Thanks again!
Sorry I misunderstood the preference of an alloy piston compared to a cast iron.
What is in your view the biggest advantage of having an alloy?
Indeed I also have cast iron ones found only so far.
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In broad terms an alloy Villiers piston is 1/3 the weight of its cast iron equivalent. Thus the engine runs more smoothly as there is so much less weight moving up and down the cylinder. Further to this it takes much less power to move the lighter piston in the same fashion so the extra power required to move the heavy cast iron piston is now available for the rider to take advantage of. Finally the alloy piston disperses heat better than cast iron so the engine can be worked a little harder with no detriment.
So the upshot is the same engine with an alloy piston runs more smoothly, revs more willingly, is a little nippier and stays a little cooler.
Cast iron has its virtues. Given care a cast iron piston will last indefinitely running in a cast iron cylinder. It is easy to work and requires little if any heat treatment. It is also cheap. In some circumstances an operator may value these virtues above those offered by an alloy piston.
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There seem to be a lot of GY-prefix engines used in little Francis Barnetts in the 1930s, like this one: https://cars.bonhams.com/auction/29728/lot/229/1933-francis-barnett-148cc-lapwing-27-frame-no-c27176-engine-no-gy-4934/
Some of them have a GYF prefix. What does the 'F' mean, and was there a serial number reset to go along with it?
Leon
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Another nice example
https://andybuysbikes.com/bikeshtml/6915cve.html#
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Villiers would add an extra letter to the engine prefix for various reasons, not all of which I yet know but no matter what the underlying engine remains the same.
I do know the extra ‘F’ refers to FIXED ignition. Previously Villiers had clamped the magneto backplate onto the protruding main bearing bush. Slackening off the clamping screw allowed moving the backing plate back and forth to get the ignition timing just so. Villiers even fitted an advance and retard lever to the backplate to facilitate this. It didn’t work. Getting the clamping force just right, loose enough to move but tight enough to stay put otherwise was nigh impossible. Some factories fitted some sort of device to hold the lever in place but these have mostly disappeared over the years.
The idea of slackening off the clamping screw to tweak the ignition just so remains a good one, just make sure you tighten it up again afterwards.
In the end Villiers not only dropped the idea but went further and mounted the backplate permanently in a fixed position, hence the additional ‘F’.
This came late in the XII-C’s life. The earliest engine number I have is GYF 10421, first registered in May 1939.
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Thanks 33d6, very interesting. I wonder if Villiers reset their numbering for the GYF engines, if only because of this bike that is claimed to have engine number GYF2612: https://www.handh.co.uk/auction/lot/61-1937-francis-barnett-plover-41/?lot=10584&sd=1
That said, I only take numbers seriously when I have seen them for myself! Plenty of scope for mis-reading or mis-transcribing.
Also difficult is engine swaps: I assume the '1939' Andy Tiernan bike could easily have an earlier engine fitted at some time?
Anyway, my interest in these little 147/148cc engines come mostly trying to understand better the little Australian bikes of the 1920s, mostly Elliotts here in SA and Waratahs in NSW. Engines are now under control, but frame numbers are problematic. Waratah had mostly just Sun numbers, having been built (I believe) in the UK, whereas Elliott built up their own frames and stamped their own numbers, sometimes very badly! But after half a century of cobbling together cheap and cheerful little vintage bikes its a bit hard to make sense of some of them. Others with established provenance make perfect sense!
Cheers
Leon
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As you remark Leon, placing trust in auction house puffery is moving on to shaky ground. Even the auction houses warn you against it.
So far as engine swaps are concerned a major virtue of Villiers engine was they didn’t change from year to year so you could safely exchange engines without worry plus of course for years Villiers powered bikes were so poorly regarded that it made more sense to replace a worn out engine with another less worn secondhand one than actually spend money refurbishing one. After donkeys years of these old bangers being mauled about its bizarre that we should expect the numbers to match up.
As you say, it’s only the ones with an established provenance that make sense. Provenance is all.