Having started 2024 as the highest car on the planet, almost 6,000 metres above sea level near the summit of the highest volcano on earth, Daisy the Mini hasn’t had an easy year. After descending the mountain and making its way back out of the Atacama Desert, its 2,500 mile drive back across Uruguay wasn’t easy, with a variety of serious oil leaks and head gasket issues making things increasingly interesting as we rolled back across rural Argentina.
Our resident road tripper, Ben Coombs from Pub2Pub Adventures, rounds up what went wrong and how they are methodically fixing the mechanical issues.
Once back in the UK and with a new head gasket fitted, things improved, but not completely. Trips to various car shows and events brought about further leakage, head gasket failures and poor running, which gradually worsened until this October, when a trailer was required to get Daisy from Devon to near Northampton for ClassicLine’s Mini-centric meet. For a car that started the year on the top of the world, this was a somewhat ignominious occurrence. Things had gone too far; the decline had to stop.
On Daisy’s return from ClassicLine’s rather awesome All Mini Breakfast Meet, at the rather awesome Industry & Supply near Northampton, it was time to get to the bottom of the issues. A leak-down tester was purchased and showed a significant amount of air escaping from the crankcase, suggesting faulty piston rings were the problem. So, a full stripdown of the engine was needed to confirm the diagnosis – a rather daunting prospect, for someone who has never done such a thing.
But it turns out that, provided you’re methodical and don’t mind religiously following the Haynes Manual, it’s not so difficult a job. And once everything is apart, it can be rather revealing, too – in Daisy’s case, we found that the top piston ring in every cylinder was broken, which explains the air escaping from the cylinder into the crankcase.
The general consensus is that, prior to my buying the engine, it had been fitted with new piston rings, but the cylinders had not been rebored. This is backed up by the receipts which came with the engine when I purchased it, and meant that the new piston rings had been hitting a wear ridge at the top of the cylinders, which had fatigued them, before each ring cracked into two pieces. And with this revelation, suddenly lots of things began to make sense. The lack of compression explains the myriad of engine issues we experienced at altitude – the poor running, lack of power, absence of driveability and extreme starting issues at over 5,000 metres up, where the air density approaches half that of sea level. The over pressurisation of the crankcase would explain the oil leaks from every gasket, and ultimately perhaps too, the knock-on series of head gasket failures.
So, time to fix this. Quickly.
On receiving the newly overbored block back from the machine shop, along with a shiny new set of oversize pistons and piston rings, I had less than two weeks to get the engine back together, bolted back into the car and tested, before driving Daisy to the NEC where it was all set to be displayed on the British Mini Club [LINK to NEC BLOG HERE] stand.
Fortunately, it turns out that once again, provided you’re methodical, reassembling an engine isn’t so much difficult as simply daunting, and it was back together and fitted back in the car after four fairly busy days in the workshop. To run in the new piston rings, the engine is now temporarily fitted with an SU carburettor in place of the supercharger, so the new carb was cleaned up, and set up using the air-fuel gauge handily installed on Daisy’s dash. It all went down to the wire, but on the Wednesday evening before the big show, Daisy was all set to head up to Birmingham for a long weekend under the bright lights of the show.
But some things aren’t meant to be.
With the engine running sweetly on its new carburettor, I went to manoeuvre Daisy out of the workshop, only for the steering to suddenly stop responding to my inputs with anything more than a grinding noise. With one problem seemingly solved, another had taken its place. The splines on Daisy’s 50-year-old steering column had failed, meaning the wheel wasn’t moving the steering rack. A new column was needed, and as Daisy had 18 hours to get from Devon to Birmingham, this meant she’d be missing the show.
Daisy is now sat in the workshop awaiting a new steering column, which we hope to fit next week.
Once that’s done, we can get on with the job of running in the new piston rings, which will hopefully see her through the next few decades. And while we’re doing so, we can ponder the question – if Daisy made it to an altitude of 5,920 metres with broken piston rings and a failed head gasket, just what might she have achieved with a healthy engine?
It almost makes us want to go back to the Atacama Desert and find out…
