Strange tale this, or is it? On holiday in Spain in the summer, 75mph on the motorway near Santander. Throttle momentarily sticks, then we're firing on 3. Pull off m/way (near an exit!) and coast downhill to a small village and a very friendly bar. Meet Oscar, car enthusiast like me. Bonnet off, plugs out check compression, none on Nr 3. Clearly a problem. Luckily have breakdown cover (thankyou to Footman James), car eventually repatriated (a month but no problem as it is not used daily!), holiday and camping continues in a rental Corsa :-(
Thanks to moving house in September have only just managed to sort out the problem. Car is a Supersprint with the K & N's bolted in place. Weber trumpets held in place by the usual tabs on their flanges, with spring washers and nuts. Appears that one of the tabs had vibrated loose and been sucked in. I kid you not!!!! Steve at Vulcan had heard of this before. I have just finished re-building the engine, decided to stay with the cast pistons, of AE make but slightly different design, but have replaced all four. Quite a painstaking job, but enjoyable Nr 3 piston was peppered with small debris marks and Nr 3 inlet valve was bent, so replaced this valve and the exhaust valve as well. No bore damage on the AX block, but I did hone it lightly. Sump removal hampered by a non split sandwich plate to the gearbox, managed to cut in the recommended 3 places with a B & D Wizard tool (like a Dremel). The Wallage book was very helpful.
Finally and importantly, all 8 tabs to the Weber trumpets are now loctited and tightened