Head rules heart
Without actually intending to, I’ve bought a new cylinder head. But this isn’t any old cylinder head – this is the legendary 12G 295 head, the Holy Grail for owners of 1098cc A-series engines. The quest for one is something you might hire Indiana Jones for these days. This is the factorytuned version of the head, used on 998cc Coopers and MG Midgets and 1100s. With larger inlet ports and valves, plus a more rounded combustion chamber, according to A-series engine guru Dave Vizard, fitting one of these to a Minor engine adds 6bhp. That’s quite handy when you only have 48bhp to start with.
By some miracle Bryan ‘Indy’ Gostling – who I bought my Minor from last year
– found an apparently good one while having a clearout of the Morris Minor Owners Club stores. He posted it on Facebook with a price tag of £175 and I pounced. Nostalgia was another motivation; I fitted one to my first Minor – my very first step on the tuning ladder. Mind you, back then you could still find 12G 295 heads in breaker’s yards... and pay about a tenth of today’s prices for one.
A big lump of cast iron, it’s not something they look kindly upon at your average local Post Office. But I avoided having to make another trip to deepest Norfolk to collect it – Bryan had a stall booked at North Lopham Autojumble, near Diss, roughly halfway between us.
It only seemed right that the Minor should be used to collect its own treasure, so we set out early on a Sunday for the car’s first decent journey since I drove it home from Bryan’s last October. The few bits of work carried out in the meantime have paid off because it ran beautifully, cruising happily at 65mph with just the odd micro-stutter that had me wondering about old fuel or if a tweak was needed to the carburettor adjustment. Mental note made to check the colour of deposits on the spark plugs later.
The head was as good as described. The mounting face will need a skim to clean it up, but unless it has already been done in the past it will need some metal shaving off it anyway to get the combustion chambers down to the right size, because they’re larger than on the standard heads. I’ll need to get a burette to measure what the volume is, then compare it with the data in Vizard’s excellent book, Tuning The A-series Engine.
That will be a project for next winter though. We hopefully have the more pressing matter of a house move to deal with first. And anyway, I’m having too much fun getting used to the Minor as it is for now to want to take it off the road.