THERE I was, the disassembled Weber carburettor I was rebuilding strewn before me on the kitchen table, when I started giggling to myself. The petrol fumes may have been a contributory factor.
"The state of you," said I to the strange person I had become. "Two years ago you thought a carburettor was a type of Italian bread. Probably nice with a nub of provolone and a tumbler of pomegranate juice. And now look, yer a filthy greasemonkey."
"Filthy and lovin' it," said the new me. My former self had a point. Avowed cyclist to obsessed petrolhead in three short years.
I'm not ashamed to admit that at the time I bought the Duchess, a 33-year-old BMW 2002, I would have struggled to put air in a car's tyres without a Hindenburg-esque disaster ensuing. And a bonnet? That was, for me, like having a predilection for shoplifting or supporting Sinn Féin - something never to be raised in polite company.
And now? My daughter puts it best. "What's Dada doing?" I once heard the golden-haired little angel asking her mother.
"Fixing his car, Missy Moo," answered Mrs Emissions with the resigned sigh of a classic-car widow. "It's broken."
"Dada's car is always broken Mama," said madam. Out of the mouth of babes, eh?
Through sheer necessity, I'm becoming quite adept at engine-rummaging. My mechanical mentor, Beemer don Tom Curley - to whom all praise, etc - says I've a learning curve steeper than a ministerial pay rise.
Between us, we've transformed the Duchess. The list of refinements and tweaks is too long to list. Even if it wasn't, I'd rather not traumatise my accountant - and wife - by doing so. Suffice to say, she's had more new bits in two years than a plastic surgeon's trophy bride.
It hasn't all been plain sailing. A little knowledge is a dangerous thing. Especially when flames are involved. I was once having terrible trouble tuning the carb. Exasperated, I stuck my head over it to see what was wrong. Predictably, that's when it backfired, shooting a column of burning petrol skywards. It could have resulted in a nasty soot-smudge on the bonnet's underside . . . had my face not been in the way. I wasn't able to smell anything but singed hair and incinerated snot for weeks.
And many's the time I've fiddled with a perfectly operational engine, only to retire mere minutes later, cursing my unfounded self-confidence as I realised my inept meddling had banjaxed it. "Err, Tom, I've done something silly again . . ," I'd mumble sheepishly down the phone.
All the frustration and anguish of life with the Duchess has made me realise classic cars are like recalcitrant children. Bottomless financial pits, always shedding fluids at inopportune moments, bound to break your heart eventually. But you'll never stop loving them.
Which is how I feel about her. She may not be the sleek Bavarian princess of yore. But a bit of a nip-and-tuck here, a bit of fiddling with her plumbing there, and she's now more of a goer than she ever was when she tore off the production line all those years ago.
That said, she's still not quite perfect. My current prime concerns are the rust spots bubbling up on the bonnet and passenger door, giving the aged noblewoman the complexion of an acne-ridden teenager.
Worse still, the foam has perished in the driver's seat, meaning I get a spring enema whenever I go anywhere. Plenty of bizarre people out there would pay good money for the pleasure. I'm not one of them.
The truth is, no matter what I do, I'll never truly be satisfied. You clever folk will, if you have even the most basic grasp of Buddhist theory on the nature of desire, be aware that in that way madness lies.
Bring it on.