Sunday 26 June 2011

Engine goes in, engine comes out..

After a recent trip to Bristol (about 360 miles round-trip), it became clear that the 328 engine was not in a viable condition. I reached this conclusion when I had to stop at a service station to put in over a gallon of oil at motorway prices (about £70). My best guess is that it's using about 1 litre per 200 miles. I've also learned that Jason's car with a 3.2 litre engine does about 30-32 mpg, so the 18 mpg that I'm seeing is nearly half what it should be. Plus, there's the cost and hassle of replacing the oil separator valve every so often because it can't handle the volume of oil coming out of the crankcase.

So I started searching Ebay for a new engine. Initially I was planning on a straight swap with another 328 for cost reasons, but ended up, inevitably, with a 3.2 litre M3 EVO engine, good for about 320 bhp, or around 450 bhp / ton - a bit less power than an R500, but a lot more torque, so performance should be acceptable. If it works, which remains to be seen. I figured that if I was going to go to all this effort, I might as well at least get something positive out of it. Plus, the redline of 7600 (with 8000 safely achievable with a little light remapping) will be considerably more fitting for a lightweight sports car than the 6200 of the 328. The only real downside of the M3 is the cost, which is considerable: I definitely won't be getting new wheels any time soon :-(

I picked the engine up on Wednesday from a garage in London. They had a couple of BMW race cars outside, so hopefully they know their stuff. They bought the engine as a spare, and rebuilt the bottom end with some new bearing shells and con rod bolts, so it ought to be in good condition.

After a bit of engine inspection and Ebaying the missing bits on Thursday, I started the swap on Friday night. Thanks to Jason and Rad-tec for sending me the bits I needed so promptly. Pictures follow:
Most exhaust ports looked like this...



But 1 and 6 looked like this. I'm not too concerned - the seller reckons it has just leaked through from storing the engine upside down (on a stand I assume). Makes sense as pistons 1 and 6 would be in the same position.

Old engine coming out.

Engine coming out. Surprisingly, not too hard doing this on my own.

Impromptu flywheel locking tool constructed using the awesome power of two hammers. This worked rather well.

Home-made clutch alignment tool. Did the job nicely.

New engine ready to go in. Note trolley for sliding gearbox onto engine.

Chassis adjusted to allow the slightly longer engine to fit in.


Unpleasant surprise - I thought the stud had been cross threaded. Happily it turned out to just be a bent stud. Phew.

All in all a fairly painless weekend (not literally, obviously - I managed to stab my finger with a stanley knife requiring swift application of superglue to stop the bleeding) but successful. I didn't get the new engine in as one of the gearbox bolts snapped when removing the gearbox from the old engine - since these can't be put in with the engine in the car, installation of the new engine will have to wait until I've obtained a new bolt. Otherwise everything is ready to drop the new one in.

Most pointless mistake of the weekend: spending an hour with the angle-grinder getting the old clutch off because I needed to reuse the plate which sits between flywheel and engine, and the bolts holding the clutch on had rounded. Once I had the flywheel off I realised that the plate, instead of going all the way around the crank, was basically U shaped and could have easily slid off without even loosening anything.

Getting the gearbox on the new engine was a bit of a faff, but the trolley helped a lot. The best method seems to be: adjust crane to get engine the right height against the gearbox. Then adjust the engine using the load-leveller so that the gearbox lines up flush vertically against the clutch housing. Readjust height slightly. Gearbox then goes on pretty painlessly. I didn't have a clutch alignment tool so I had to wing it with a socket extension wrapped in tape. As it turned out, this did the job just fine.

I can't compression test the engine until it's got some oil in it, and I can't get oil in it until the adapter turns up from America (I've gone with a very shiny custom oil cooler - the only downside being the difficulty of getting a suitable adapter). Hopefully that will be soon. Then I need to figure out the loom, and make the necessary adjustments as the loom is off an SMG gearbox car (I believe it's a simple case of jumping a relay... I just don't know which one). Then it's car back together and drive gently up to Fibreform to get the diff mount beefed up and to replace the chassis rail which I removed.