I found this Vespa Lambretta piston stop tool on eBay. Just over a tenner delivered and has the correct thread for the A Series. The Audi one I bought to replace the earlier purchase of this scooter item does not fit the threads.
Why do I need a replacement? Because I didn't use the recommended technique to wedge the crank with a piece of wood prior to undoing the crank nut!
It's taken a while to retrace my eBay purchase, but for info, here is the item:
I remove the crank shaft damper bolt with an Ingersol Rand 2131 impact wrench, that delivers 600 lb.ft of torque in reverse. No wedging needed. The nut is loosened with a single, one second burst. This is also useful to remove pulley nuts on Alternators, starter gear nuts and power steering pump nuts, without having to hold the pulley stationary.
While a crank stop tool is useful, I have a TDC tool that uses a measuring plunger. You can also acquire a fitting that will allow the use of a dial indicator to find TDC. This type of timing tool is often used for motorcycles, or other small engines.
Piston stops like the one shown are often sold by spark plug thread size. The BMC A uses a common plug size to not only Euro 4 cylinder engines, but American V8s as well. It should not be hard to find an adjustable piston stop tool for finding TDC with the correct threads.
When I do cam installations, I have the head off of the engine, so the dial indicator works perfectly well with my timing wheel.
