So I booked Charlie in and ordered the bits from new MINI parts supplier BMS Direct, who amazingly got the timing chain kit (£160 with sprockets and guides) sent out the same day and to me for the next.
I took all the parts to Forshaws and they started taking Charlie apart to do the job. However, once the new kit was opened we realised it didn't come with replacement tensioners. As it happens, on the strip down of Charlie they found that the crank pulley was pretty worn and in need of replacing at the same time - so it was back on the phone to BMS who promptly sent out a tensioner (£47.99) and a new crank pulley (New £230/Used £100) and auxillary belt (£19.99).
Fortunately the garage was OK with keeping the MINI there and lent me their courtesy BMW 316i which was pretty old and used to say the least... bits falling off!
The boys at Forshaws used the extra time to strip down the engine ready for the new parts when they arrived the next day. I'd asked BMS to send the items direct to the garage, so by the time I arrived the next day, they were almost finished and I'd missed out on some photos.
The crank pulley lay on the floor ripped apart with the force of prying it off - and the senior technician, Chris, explained how a couple of o-rings and seals had worn and needed replacing too. With no local supplies, we decided that gasket seal would need to be used to prevent any oil leaks from the timing chain cover.
Whilst on paper, and looking at the engine, it seems like a big job - it looked quite methodically easy. Removing the intercooler, coil and leads, rocker cover, engine mount and you're not far off. The difficult bit is when you need specialist BMW tools to remove a puller or whatnot... and that seems to be the trouble - manufacturers are making them unserviceable to owners, without extortionately expensive tools. I'm sure there is a work-around, but when the car and the parts cost so much, it's not quite the same as accidentally trashing a £10 part on a classic Mini!
With the new chain on, it has a bronze link to help line it up, and the new pulley and belt, I was hoping the squeaking and rattling had gone and Charlie would sound more MINI-like rather than a dirty diesel (although it's a petrol!). So once reassembled, the moment of truth... squeaky rattling diesel or happy quiet petrol? See the video below...
Disappointed doesn't cover it. The advice received is, that they've discovered that the idler pulley is worn and is the cause of the squeaking - and most likely my lack of 'pull' when I first put my foot down. Fortunately, the job to replace the idler gear isn't as tricky as the timing chain, and apparently can be accessed without pulling the engine apart. That's some good news. But hey, I suppose at least the timing chain rattle has gone and that's one major job tackled.
I had a word to the big bossman, Tony Forshaw, about the misfire and he took the car for a spin to see what he could garner from a drive. After plugging in the latest BMW diagnostic tool he didn't discover anything new aside from what we already knew - a misfire on cylinder four.
He advised me that it could be the coil and leads, and that would be the first area to replace and check. I was pleased he had taken it upon himself to try and address the issue as it was and still is a big bugbear - misfiring when at idle. So for me, the next step was to get a different coil pack and some new leads and sparkplugs to test.