Locked up

I enjoyed your piece on the project Triumph, well actually the whole magazine, as always.

You mentioned the newly refurbished Triumph engine had ‘locked up’. This is something that is quite common on rebuilt engines that are left to stand for a time.

I come from the automotive trade and what you experienced is something we referred to as ‘frozen’ – not in the literal sense, but of all the newly installed components, some have stuck in place.


Usually it’s the piston rings, although well lubricated, can, over a short period of time, squeeze the oil out from between the bore and ring contact area. This can cause the rings to not want to move without a bit of persuasion.

This can be more frustrating the bigger the engine and the greater number of cylinders and the sharper some of the edges to newly machined faces, as the tendency is for more than one set of rings to ‘play frozen’.

It’s usually brought about by delays in part supplies or, as in your case, other jobs needing to be done.
It affects four-stroke engines more than two-strokes, and I’ve witnessed engines being taken apart after rebuilding, due to someone thinking the worst, only to find nothing amiss.


Biggest mistake on multi-cylinder engines is mis-matched connecting rod caps, which will lock an engine up solid.

The Greeves ‘Stonebridge’ in the same issue sparked a memory from my time as a college lecturer, teaching motor vehicle studies.

Introducing myself to a class of first year apprentices and noting each student’s name down I came to a surprised halt when one 16-year-old gave his surname as Stonebridge.


Was he related to Brian Stonebridge? Yes, “my grandad was named Brian.” There then followed a friendly exchange of questions and answers with me discovering that this was indeed the grandson of the late Brian Stonebridge, but unfortunately the lad had little interest in the past and had not realised quite how popular or famous his grandfather had been or was.

It seems that too many young people have little knowledge of their parents or grandparents’ history. This was something I tried to encourage from that meeting to this day, knowing where you came from.

I am just as guilty of the same ignorance as I only recently found out that my grandfather was a mechanic and not, as I had thought, a factory machinist.


Not only that but he was a partner in a garage in Stevenage, Hertfordshire, and raced motorcycles at the IOM.

My aged aunt has a glass vase with some entries etched onto it, something I have yet to see, and history to chase down.

Tony Proctor

Thankfully the engine lock was easily solved, even the weight of the socket and bar free’d it off without even any pressure. As for family members being unaware of their elders’ involvement with motorcycles… it is a two-way street as while I knew my dad had been involved in motorcycle sport he rarely let much information out and I thought he’d finished with it in the Fifties until I started in the Seventies… turns out he was involved much more and never let on.

Read more Letters, Opinion, News and Features online at www.classicdirtbike.com and in the Summer 2020 issue of Classic Dirt Bike – on sale now!

Enjoy more Classic Dirt Bike reading in the quarterly magazine. Click here to subscribe.