Villiers Mk 15

In the absence of photos that can help confirm the type of your engine we can perhaps help with some general observations re the problem that you have.

 Was the engine fully assembled and free to turn before you set about the overhaul? 

If the engine was indeed complete and maybe in a running condition it rather points the finger of suspicion at something that has happened during assembly by you so should be easier to overcome.

Has the crankshaft been removed from the engine? If so have any thrust washers been fitted to the crankshaft in their correct locations to avoid holding the crank over to one side.

Has the ignition back plate been refitted to the crankcase using a thicker gasket than standard? If so this could move the coil assembly away from the engine block and closer to the inside face of the flywheel.

Hope this helps.

In addition to Hillsider’s questions . Before you started on the “restoration” was the engine assembled and free to rotate or was it a box of bits?
I have 1955 and 1960 manuals but unfortunately I’ve just discovered that the 55 one has the vital pages missing.The flywheel part numbers in the 1960 manual are all R numbers. Looking at the crankshaft and crankcase assembly there is an item 32/EM545 Shim, bearing packing - use as required. This or these would appear to go between the mag side ball bearing and the mag backplate , and, by default adjust the amount of crankshaft protrusion into the mag and assuming the correct flywheel , correctly seated on the crank’s taper , the clearance between it and the internals .

So going back to your original post, what was the situation at your starting point, and what has been the extent of this “restoration” ?

Thank you Hillsider.

The crank was removed and new bearings fitted. All shims that were originally there were replaced. The bearings are the same size.

The motor was damaged when I bought it. The exhaust valve had rusted slightly open and someone had tried to start it resulting in a bent pushrod. The exhaust valve had to be replaced because of a very ordinary home repair job. I cannot recall if it turned over but I don't think it did. The piston shows no signs of hitting a valve and the valve showed no signs of being hit although there was some damage to the top of the piston which was directly under the spark plug hole and looked like the piston had hit something. I had the right spark plug in it and this had been in it for some time as it was rusted into the plug hole and took some getting out.

I have done the same work on a Mk 7 and a Mk 10 and have not encountered this problem although it looked like neither of those engines had been apart before and neither of them had any internal damage. 

I have attached some photos. The flywheel only hits in one spot as can be seen in the underside photo.

Not seeing any image, possibly the “insert” button wasn’t pressed .  If we assume that it is the correct flywheel , are there any signs that it may have been damaged / distorted by a previous attempt to remove it using a legged puller as opposed to relying on the self extracting nut?

Sorry about the photos. 

There were two shims behind the bearing on the flywheel side which were replaced. The engine was assembled when I bought it but it was damaged as stated previously. 

I am thinking of having the crank checked for straightness and I'll have to have the flywheel checked also although there are no marks on it. When tightening it it seems to want to go too far onto the crank. It is not tight until it is very firmly up against the coil plate. Being second hand with an unknown number of owners and who knows what has been done to it does not help of course. The engine turns quite freely without the flywheel with no binding anywhere although there is no end float.

Certainly worth having the crank checked out , but it may be worth trying assembling with no shims , and if that’s free, with one. That’s assuming that the interference is of an axial nature ( end float positioning) rather than radial ( crank or flywheel running out of true) .

Thank you for the advice all. I've had the crankshaft checked and it is not bent. The flywheel appears to be out of round according to the dial gauge. It looks like someone may have hit it with a hammer to break the taper probably not knowing how the flywheel is removed on these engines. Part of the problems of buying an old engine I suppose.

Can anyone tell me if a Mk 10 flywheel will fit the Mk 15. I am having trouble finding a R326 flywheel although that number is not listed in any of the parts books I can find.

Don’t know the answer to that, but one of my manuals covers the Mk15 and Mk20, so the flywheel is more likely to be common to the Mk20 rather than the Mk10.  If the flywheel is distorted , I would think that it’s been caused by the use of a two leg puller rather than hitting it, which  would have to have been pretty brutal to distort it. . Are there any witness marks from hammer blows or puller legs ?