After another seemingly long hiatus there has actually been progress in the background in terms of getting the Q4 back on the road!
For a while and despite having the carburetor professionally refurbished, adding quality electronic ignition, refurbishing the electrics etc, it still wouldn't run without either it popping and banging or without it needing petrol pouring straight into the carb. Clearly something wasn't right! The hunt for the guilty parts or parts began...
First we discovered that the choke disc in the carb had been put on the wrong way round. Just shows that even pros can make mistakes sometimes! Apparently they had only ever seen these carbs with the choke cable coming in from the top (rather then horizontally) so assumed.....
That done it still didn't work and just to add insult to injury it backfired so much that it blew the silencer apart. Okay, it was thin and knackered but..... So another job to do, luckily with some fiddling a Bedford RL silencer fits!
Still no luck and after some beard / head scratching the possible reason emerged... A pressure test of the cylinders showed that they were all around 75 psi (when you'd expect well over 100 psi normally). Now with an engine that's only done 1,700 miles it's unlikely to be wear in the cylinders. So it suggests that the valves aren't sealing. With the manifolds off it opened up the horror of masses of black coke on the insides. So, the culprit is found but that will now involve whizzing the head off too to clean it all out. Why? We suspect that over the years it's been started regularly but not for long, so primarily on the choke, so the carbon has built up but without a good run to burn it all off.
Finding new gaskets could have been an issue but thanks to a steer or two through the Commer Q4 owners page of Facebook and the Historic Military Vehicles Forum, Speedy Spares in East Sussex turned up most of the gaskets needed with the help of some 60 year old parts lists. So, a sweet-running Commer isn't far off.......
