Swap your oil when you want, no engine has come to harm from too frequent oil swaps.. Most oil related defects come from people driving with too little oil, not from aged oil. At least thats what VW and Honda R&D agreed upon when I worked there. That said with the diesel downsizing/power upping there has has definitely been a steep rise of boost pressure.
Change the filter every 6K and your calibrated automatic oil change system will be fine Is it a leak due to running synthetic or blow by?
Well, the whole rear subframe can be dropped out, so shouldn't be that bad. I'm thinking of doing a full rebuild while it's out and possibly going down the supercharging route. I don't know if it really has potential as a project car though (67hp is nothing, even when the car's only 760kg) plus it's becoming a classic. I might just take it off the road after this summer is over and get somethng more practical (or just go without a car, I don't really need one).
Oooo, I doubt it'll be just a ring job if it's blowing that much by already as the pistons must be slapping around in there like skeletons fu*king in a tin can. You'll potentially be facing a re-bore and new over sized pistons. I wouldn't throw forced induction on that engine after a rebuild, if you want more powers, then source a low mileage engine to abuse.
My brother had his 225 for years and the only trouble with it was his gf leaving the handbrake off one morning and it rolling down a hill smashing up a load of cars. Oh and the Aircon needing a bit of regassing. You can up a nice one for about 3k, they aren't depreciating much more than that atm and can still be coaxed up to 40mpg but you will absolutely hate yourself for it.
The clock reads 46000k (~30000 miles); you don't get fewer miles than that! (Possible fraud at some point though) Apparently it's a common problem with the E07A, others havs done rebuilds with mixed results. The other option to forced induction is fitting high comp pistons, high rate valve springs and bumping the rev limiter to 10.5k or so.
On the rebuild go high comp as new pistons and a bore grind should already be considered for the rebuild.
Just to let you know, my brother got a z4 today. Paid £6.7k for an 04 plate 3.0l with 45k miles on the clock. It was in lovely condition, almost faultless. I didn't get a chance to drive it, but had a spin in the passenger seat and it was nice and comfy. Road noise and wind noise is obviously going to be a little louder than in my 3 series, but it wasn't bad at all, quite comparable to a French hatchback. The ride was better than I expected tbh, you feel big bumps, but it does soak up most of it. That's on 18"'s, not the more common 17"'s. The 3.0l 6 cyl engine is glorious. It's not that loud inside, but outside there's a nice burble from the exhaust, nothing too overstated though. It's certainly not slow, that's for sure. Insurance wasn't too bad either. He paid £900 fully comp, but this is his first car with 0 years ncb. He's 25, but has been a named driver on my parents cars since the age of 17. No convictions or penalties. Car registered to an address in Nottingham. He did zero haggling either. Considering I paid close to £800 at the same age for my first car (almost 3 years ago now), a BMW 320d, registered in Lincoln, it doesn't seem bad at all!
