Some vehicles have such a distinctive exhaust note that you know what they are before you see them, irrespective whether they're bikes or cars. My KTM 790 was like that, partially due to the 435 degree "big bang" firing order. Showing my age, Mike Hailwood's 1960's Honda 6 cylinder 250/350cc race bikes arguably had the best exhaust note of any i/c engine ever produced (HERE). I've also read that the crisp exhaust note of the first and second generation Mazda MX-5 Miata was deliberately engineered to mimic the Lotus Elan, which allegedly provided the inspiration for the Miata. Similarly, the 1.8 litre MGB and GT has a flat, distinctive burble. Here 'tis:
I love the sound of our GT echoing off roadside cliffs and buildings, particularly on downshifts. The human ear is a wonderful thing and a few days ago, it didn't sound "quite right" - call it a "gut feel" if you prefer. A quick inspection didn't reveal anything and I was left wondering whether it was my imagination. The following day, we were returning home from lunch at a local beach cafe and the exhaust note was definitely louder and a little different - time for a proper look when we got home.
The problem was obvious when shining a torch underneath - a hole around 20mm diameter had appeared near the entry to the muffler. A closer inspection revealed that quite a bit of the area around the hole was paper thin. The external paint on the muffler was fine so clearly, it was internal corrosion which had caused the problem. It was a regular occurrence on older cars with a lack of corrosion-resistant materials. Short journeys also contribute to the problem where exhaust systems don't get sufficiently hot to evaporate moisture. This was certainly the case with the previous owner (custodian?) of the MG.
Living a fair distance from major centres, getting replacement parts either involves mail order or a lengthy trip in one of our other cars. A temporary fix was in order until a permanent solution could be organised. A tube of exhaust cement was discovered in the shed and the recycle bin was raided for an empty aluminium can of alcohol-free cider! Half an hour later, a patch had been cut and wired in place, and a gentle drive made to cure the cement. A complete success and back to the typical MG exhaust note!
Just in case the muffler was non-standard, I sent a sketch with dimensions to the MG specialist in Auckland. Fortunately, it was the correct original and they had a replacement in stock which arrived a couple of days later.
Being the eternal optimist with an hour before dinner, I set about changing the muffler. What could possibly go wrong with just two clamps holding it in place? Jack up the rear end to give a bit better access and slacken off the front and rear clamps.
Unfortunately, Murphy's Law intervened. The clamps were easy enough to remove but the muffler was stuck fast onto the exhaust system, a combination of underseal and carbon I suppose. There wasn't sufficient room under the car for me to deliver a decent blow to the front of the muffler to break the seal. No convenient underbody ledges to try and jack it backwards either.
Darn it! The only thing to do was have a word with friend and near-neighbour Bruce, who owns a garage in the village and services our modern cars. Bruce has proper vehicle hoists which give sufficient clearance to have a decent swing with a mallet to break the seal between the muffler and exhaust pipe. My initial reluctance to ask Bruce for help was the amount of mickey-taking I'd have to endure about old farts in old cars. Amazingly, he was quite restrained and within half an hour, the job was done. Bruce's king-sized mallet did the trick!
