There might possibly be one or two here who remember my father's Ulster-style special "Incontinence" (PP 7965 - still around somewhere), which was powered by a pressure-fed 3-bearing engine with modified Reliant crankshaft. Its last outing of note - in his hands at least - was the 750MC tour to Le Puy in June 1987. He was intent on 'setting the pace' and was easily first home on most legs as far as I could determine, following along at a more sedate pace in my Nippy with Mum reading the route map (hence the leisurely pace...) His car positively flew until what must have been the last night of the trip; nearing the Pas de Calais we rounded a bend and saw it pulled over on the grass verge with a lot of noses under the bonnet. It had gone 'bang' in a big way and sadly completed the journey home on a trailer.
Fast forward a few decades and I found I still had the remains of her engine, which Dad never re-built. A bit of forensic work and a cuppa with Stuart Rolt and it was determined that although the centre main had been line-bored, whoever did it had not made a new upper housing; so rather than correcting the misalignment they had simply bored it oval. In doing so they had relieved the bearing 'nip' which holds the shells in place. In time these had rotated in the housing, shutting off the oil supply not only to the main, but also to the big ends...
I crack tested the crank and had it reground - it came back a little thinner but sound nonetheless and also balanced together with the flywheel. I drew up a complete new centre main housing and had it made at a local machine shop, then installed it with the cylinder block in place and got it line bored anew, this time with fresh metal to cut. Shells were modified to fit. I didn't fancy the old rods, which had been welded, so modified a new set, helicoiling them to take bolts from below and removing the upper shoulders which otherwise foul the cams. At the same time the stress-raiser at the end of the old bolt face was ground out. Since then I spent an unexpected amount of time fiddling with the flywheel and clutch which needed a bit of re-working.
My Box Saloon needed a temporary engine while undergoing overhaul so it seemed a good time for a try-out. Despite the nuances of 'high frame' vs 'low frame' it was persuaded to fit. I then hit a wall of electrical problems which revealed the true state of neglect of my saloon! One battery terminal was half eaten away by corrosion and that turned out to be the culprit. And then - she started. First run in 34 years, almost to the day! I did 26 miles on Friday, adjusted the clutch pedal which had slipped around the shaft slightly, followed by an 80 mile round-trip to Whittlesey on Saturday afternoon - freeing up well and pulling better even in so short a time. The engine now starts with one swing on the handle, and if it isn't pouring with rain on Friday we may attempt the journey down to Beaulieu (despite much else which needs doing to the Box! There are probably too many holes in the floor to consider wading just yet).
Anyway, just thought I'd share my tale. And a question if anyone is still reading - I need a PRV spring which will give about 50 psi cut-off with the standard ball arrangement, can anyone suggest a suitable spring please? She settles down to 25 - 50 psi in normal running but the pressure on start-up is something quite frightening!
p.s. Love your video Ruairidh! That's what we've been missing all these months. It's pouring with rain down here at present!
Fast forward a few decades and I found I still had the remains of her engine, which Dad never re-built. A bit of forensic work and a cuppa with Stuart Rolt and it was determined that although the centre main had been line-bored, whoever did it had not made a new upper housing; so rather than correcting the misalignment they had simply bored it oval. In doing so they had relieved the bearing 'nip' which holds the shells in place. In time these had rotated in the housing, shutting off the oil supply not only to the main, but also to the big ends...
I crack tested the crank and had it reground - it came back a little thinner but sound nonetheless and also balanced together with the flywheel. I drew up a complete new centre main housing and had it made at a local machine shop, then installed it with the cylinder block in place and got it line bored anew, this time with fresh metal to cut. Shells were modified to fit. I didn't fancy the old rods, which had been welded, so modified a new set, helicoiling them to take bolts from below and removing the upper shoulders which otherwise foul the cams. At the same time the stress-raiser at the end of the old bolt face was ground out. Since then I spent an unexpected amount of time fiddling with the flywheel and clutch which needed a bit of re-working.
My Box Saloon needed a temporary engine while undergoing overhaul so it seemed a good time for a try-out. Despite the nuances of 'high frame' vs 'low frame' it was persuaded to fit. I then hit a wall of electrical problems which revealed the true state of neglect of my saloon! One battery terminal was half eaten away by corrosion and that turned out to be the culprit. And then - she started. First run in 34 years, almost to the day! I did 26 miles on Friday, adjusted the clutch pedal which had slipped around the shaft slightly, followed by an 80 mile round-trip to Whittlesey on Saturday afternoon - freeing up well and pulling better even in so short a time. The engine now starts with one swing on the handle, and if it isn't pouring with rain on Friday we may attempt the journey down to Beaulieu (despite much else which needs doing to the Box! There are probably too many holes in the floor to consider wading just yet).
Anyway, just thought I'd share my tale. And a question if anyone is still reading - I need a PRV spring which will give about 50 psi cut-off with the standard ball arrangement, can anyone suggest a suitable spring please? She settles down to 25 - 50 psi in normal running but the pressure on start-up is something quite frightening!
p.s. Love your video Ruairidh! That's what we've been missing all these months. It's pouring with rain down here at present!