AJS & Matchless Owners Club

Can anyone tell me why I have a letter “P” stamped on the timing side crankcase?
The bike is a 1952 AJS 18S

Well although my question has had us all stumped, Kevin Gorman on one of the Facebook pages has been in contact with the ex employee groups and has come up with this answer.

“Here you go Neil S Bonner From the man who runs the Ex factory workers Facebook group regarding the letter P on crankcases.
Dear Kevin,
Thank you for making us do more research into this very little known subject.
It appears that during that period, Terrys Springs delivered a batch of valve springs made from the wrong material which was then quickly discovered. This left the factory with no stock to continue production so a small batch of bikes was sent out knowingly with the faulty springs and the crankcases were stamped with a letter 'P' (for Plumstead!) and their numbers recorded so that they could be traced and exchanged on the customer's or dealer's premises. A special tool was made to be inserted through the plug hole to hold the valves closed so that the springs could be quickly exchanged without removing the cylinder head.
We never stop learning!
Thanks for asking the question.
Best regards
Bill”

I hope this may be of interest and help to others.

Amazing what little details emerge from a simple question!

Isn't it great that there's still people around who can still answer such queries, sadly of course that won't always be the case so now's the time to learn from people who know.

Alan

I love reading about snippets of information like this. I have a similar number stamped between the head/barrel bolts on my Panther which remains a mystery. I know of another engine in NZ with the same number stamped on it. What it means appears to be unknown though the seperate builder's identification numbers are well documented (I even have a factory photograph showing the chap that built my engine)

I have heard of, but never tried, oiled string being fed into the sparkplug hole and the engine being brought up to compession to hold valves closed. I'd be intrigued to see the tool referred to though.

Steve

Bath chain down the plug hole also has been used.

Rob C

Hi

I wonder why anyone would bother with any sort of 'tool' - surely just positioning the piston at TDC will stop the valves dropping beyond a point where they couldn't be pulled back up by hand

Regards Mick

It'd be a bit of a problem then to compress the spring and get the collets back in, Mick.

Steve

Greybeard wrote:It'd be a bit of a problem then to compress the spring and get the collets back in, Mick.

They're hairsprings aren't they? - I fit the collets and carrier to the valve stem and then insert the springs - with the head on the bench I don't bother packing up the valves

Regards Mick