Villiers timing.

[joegrgraham]

Evening all,
Firstly may I apologize for missing the AGM, I was planning to attend, then totally forgot…)
I am slowly emerging from hibernation now and today I ventured into the garden, the plot is finally starting to dry up, time to get it turned over….
The Trusty still refuses to start (must sort that carb) and the Merry Tiller started beautifully but then shredded its belt halfway through the garden. (at this rate I will be going to Lotmead with Grandads spade….)
So, I decided to revisit the Howard Bantam I was given back in the Autumn, I got some encouraging pops and farts out of it, so I’m somewhere close, but clearly not close enough with the timing.
I have the manual, so I know the points gap and degrees BTDC etc, I was just wondering if anyone had any tips/hints not in the manual, for timing it up accurately?.
Its a Villiers MK15, with a new magneto set up from Meetens.
Thanks,
Joe.

[stuart]

Set the contact breaker gap to between 012″-015″ and leave the flywheel slightly loose on its taper so it can be turned whilst the crankshaft remains stationary.Set the piston at 1/8″ BTDC (remove cylinder head to get an accurate position and only refit the head after the timing has been completed).The flywheel must be turned so that the points are just beginning to open.Retighten the flywheel ensuring the crank does not turn.Refit the cylinder head.If the carburettor and fuel system,the ignition system and the compression components are all in good order then you will have no problems :):)

[joegrgraham]

Thanks Stuart,
I’ve set the timing tonight, as you’ve suggested. Just got a couple of little jobs to do on the head, before it goes back together, so will keep you informed as and when.
Joe.

[joegrgraham]

Afternoon everyone,

Spent some time with the Bantam today.
Put her all back together, pulled the rope, cough, pulled again, and she fired!!!(briefly).
Pull again, cough, pull, pull, pull, rope slips, hit hand on vice, say bad words, pull and nothing!
Plug out, no spark. Throw away plug, try a different one, nice blue spark. Plug in, pull and nothing!.
With the plug resting on the top of the head and spinning the engine with a drill, I get a nice fat spark for the first few revolutions, it then becomes intermittent before disappearing completely.
Is this likely to be duff plugs (I am just using old ones out of the spares box for now) or do I need to go back into the magneto?

On the plus side, the Merry Tiller had a new belt and pins today, so at least that’s back in action, if it ever dries up!.

Joe.

[andyfrost]

Joe , firstly try what you have been doing DIRECT off the end of the HT lead and get back to us.
NEVER try or use old plugs , there’s usually a very good reason why they were taken out and “put in the spares box” in the first place.
From your description it does sound like a duff magneto , if this proves to be the case , have it professionally tested and go from there.

Andy.

[wristpin]

You say “new magneto from Meetens” . Is that new new, or new used? If the latter and the points are clean and shutting squarely,I’d be inclined to suspect the condenser (square one hidden under the points). Bit of a faff to get at but relatively cheap to try a substitute. Other than that you could replace the points and condenser with a Meco electronic module which makes the ignition system almost winter proof.

[joegrgraham]

Afternoon,

Had a quick look today, tried the suggestions, and not a sausage on the spark front.
Back into the magneto for a look…………
At least I’m becoming adept at stripping a villiers engine!

[charlie]

Check wires to points for breakage/open circuit. I remember my father had this happen once.

[joegrgraham]

Hi Charlie,
That’s my next move, I remember an article in Tractor magazine where he was chasing a similar problem in a Barford atom.
Joe.

[stuart]

Ref the ignition timing Joe…….i have on my workbench a Villiers MK15HS (the High Speed version of the MK15) which I have dug out as I am going to sell it.It had a +020″ rebore and new genuine Villiers / Hepolite piston kit many years ago and has never been used since.Anyway on this engine there is a mark on the flywheel rim and a mark on the alloy armature plate at the 12 o clock position.With the piston at TDC and with both these marks aligned the ignition timing advance is correctly set.Just remember to set the contact breaker gap first though.In my Villiers MK15 and MK15HS operators manuals I have there is no mention of setting the timing up this “easy” way.Hope you get it sorted soon.

[joegrgraham]

Stuart,
That’s interesting you mentioned that, my engine has had a +040thou rebore, so will that affect the timing settings?

[wristpin]

<In my Villiers MK15 and MK15HS operators manuals I have there is no mention of setting the timing up this “easy” way.Hope you get it sorted soon. >

I think that the reason that no mention is made of the “easy way” is that not all engines seem to have had those marks added. I’ve got just one Villiers manual,out of many, which actually mentions that those marks are added during the initial engine build.
While it may make life easy it makes no allowance for the where the points gap is set in the 12 – 15thou range. That together with a bit of inaccuracy in finding the exact TDC position (a few degrees of crank rotation where the piston appears to be stationary) can produce a cumulative error.
It would actually make setting BTDC much easier if more manuals gave it in degrees rather than a linear measurement but taking Villiers as an example, one or two manuals do but the majority don’t.

The rebore makes no difference to the timing.

[stuart]

Some Villiers engines I have had,especially the 2-stroke models like MK25C,have a “slit” or a mark on the end of the crankshaft at the flywheel end so you can visually set the crankshaft at the 12 o clock position and hence the piston will then be at TDC.The MK15HS 4 stroke engine I mentioned above has no “slit” mark though.
As already mentioned a rebore makes no difference to ignition timing settings.

[wristpin]

The “slit” is fine but unfortunately Villiers don’t provide an adjacent mark to line it up to. It’s just another judgement by eye – and is the engine sitting truly vertical anyway?!
Fixing tdc by eye or even with a dial gauge has its inaccuracies; the only really accurate way is the positive stop and timing disk method but, as has already been said, that requires a a BTDC figure in degrees, however few manufacturers provide that. Unfortunately extrapolating that from the commonly provided linear measurement requires knowledge of the centre to centre length of the connecting rod – not something that is usually readily available !
When all is said and done, on “our type of engines” a little care using the manufacturer’s data a the Mk1 eyeball is all that’s needed to achieve a satisfactory result – and maybe a couple of shots at getting it right !

[joegrgraham]

UPDATE
The Bantam is alive!!!!
I reset the timing for the umpteenth time, new plug and away she went!.
So, many thanks to everyone who took the time to contrubute to this thread, I think a little bit of everyones advice went into this one.
She is running in the picture, the ground has already been Merry Tilled, and is currently wetter than an otters pocket, so not really a fair test.
Thanks again,
Joe

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