Eagle

Penrite Superdot4 for street usage. Available in 4L if required. HPR in 20L box on special at Repco etc. Think i paid ~170 odd a year or so back. Penrite Green as it's cheap and easily available, but any HOAT type that meets BMW specs is fine. Needing to use BMW stuff is nonsense with the options around out now days. I've always used Redline oils in BMW manual transmissions as its always given me good results in regards to shift quality. Plenty of other decent full synthetic options though. Penrite Progear 75W-90, but It's a open diff im guessing so what ever you feel like putting in\spending.

Many manufactures would be out of business if that were true

It's an easy swap with a Ti donor car.

Don't see any point in changing it myself. A M40 is never going to be great on the open road and going lower ratio is sacrifice what little acceleration you already have.

Cheap imports here in NZ are offset by having to import parts to keep maintenance costs down. Hate to think how much ive spent on shipping from 15 years of buying overseas.

318ti diff would work with your car but may need flanges etc swapped with E30 stuff worst case. 318ti auto's run a 4.44 diff so you'd have to check the diff tag on yours to see what ratio its running. As for M42 preventative maintenance - Mess of pipes under the intake manifold and associated gaskets is the big one, followed by the PCV and breather hose, chain tensioner then all the usual stuff like oil gaskets\seals, intake boots, drivebelt parts, cooling system parts and hoses. Depends on how far you want to go.

If you have checked the new parts are correct then it's probably a misalignment, those plastic clutch alignment tools aren't that great for alignment compared to the proper tool. Sometimes i will use bell housing bolts to evenly draw the transmission in the last little bit its not perfectly centered (slowly and by hand and you can damage things if its not very close to alignment )

No point. Youshop is expensive and slow compared and always collects GST. Much cheaper with FCP Fedex.

Surprised it's not an auction. Had lots of good buys in Christchurch over the years.

Should come off as one piece iirc. You'll need some sort of puller to pull it off the crank (as mentioned in earlier post) with few applicable bolts to go in the pulley threads.

The shells probably won't work as mentioned above. I spend too much buying from different Aliexpress sellers to find that out, lots of spare key blades for my car without functional remotes. You can swap the rubber buttons from them over to your old key though.

M20 are a more head weakness than gasket failure, certainly not the strongest engine but they still hold up well given their age and as stated cheap\simple to repair if needed. Cam belt was always stated shorter interval than average but people driving to cambelt snap isnt uncommon in any car. Water pumps are water pumps, some go longer some shorter than expected. 4\6 of my M30 engined car experience head gasket failure when flushing the block due to neglected cooling systems, all done 330k-500k. Certainly are more susceptible but not all exclusive to BMW's of that era. A-B with minimal maintenance => reliability? Reliability usually encompasses durability and simplicity. Generally people who aren't spending money on their car all the time consider it reliable for all intents and purposes. You got to remember the average non car person can't even or doesn't want to change a light bulb in a vehicle.

The membrane just sits loose under the rubber buttons and the board. Its not suppose to be physically attached if that's what you are meaning? Not sure what you can do with the board myself beside clean it up and re flow the solder joints if you believe its not working. You can get new key rubbers and membranes and probably a replacement board off an old key from wreckers. I bought some spare aftermarket fobs off aliexpress with membranes, chip, board but you can't screw them shut without buttons jamming on. Maybe others selling ones that work but these things are getting pretty old so less support. Dealer will probably sell you one for $300-400 if all else fails

BMW's 3A and 4A equivalent engines were the M10 and M42\M44, not quite Toyota reliability but not far off. Along with late 80's M20 and M30 engines a N52 isnt even the same league from a reliability point . Even though the N52 block itself is fine it suffers from all the planned adolescence attached to it like most modern BMW's.(components, pipe work, sensors ,seals etc) Not an issue with people that have money\knowledge to maintain it, but that ain't that average consumer so its generally not considered reliable by anyone who isn't the former. I still bag M54 even after doing nearly 100,000km in 5 years. It was reliable because it was looked after and i spent a couple of 1000 replacing all the weak points. Nice engine but not from a true reliability point, even though it's far from the worst. (same situation as N52 and many other BMW engines, too many weak points ) M10\M20\M30 are all largely the same formula. Simple, under stressed and refined over many years. I doubt many people were scrapping the car because of engine troubles unlike some of some of these early N series models. BMW parts and procedures may be more readily available, but labour costs aren't getting any cheaper and that's makes up a chunk of the bill. Neglected\not have to spend money but still able to get you to A>B is the real definition of reliability for the average person.

You can still power the starter via jumper leads and screwdriver. Depends on if\how much you want to spend money on tools. You can probably get the proper M20 etc crankshaft holder tool for $100 odd, universal tool or have a holder made up locally. I use something like this on occasion which works both directions with a decent hammer https://www.trademe.co.nz/a/marketplace/building-renovation/tools/hand-tools/spanners-wrenches/listing/3247453155?gclid=CjwKCAjwvuGJBhB1EiwACU1AiX5jMefTME-xzAnnAZL5uBqfo3kVJLgOsP9n7HVFEDJt9P9Jks2lxBoC7PUQAvD_BwE&gclsrc=aw.ds Otherwise plenty of other ways involving jamming\holding flywheel, rope in cylinders, ratcheting crank pulley etc. If the motor is out then it there's is even more ways but you can probably just lift it up and take it to someone at that point as you say. You only need to remove the cover to do the seal or if you going strip\clean\rebuild. Guess you will have to decide that.

Yes. Depends what tools you have. If you dont have a big impact or crank bolt tools then you probably looking a breaker bar against the chassis rail and flicking the starter. You'd want a decent quality bar though. Also may need a harmonic puller or hub puller or such to pull that crank sprocket off

If you made a list of issues the 4 cylinders would have likely the most. But you are correct about the 6's and 8's, they aren't what id call reliable either. N series engines are just money pits in general after certain age and mileage.

FCP says backordered. Didn't realize they are so overpriced though. They seem to be around 1k else where. Few different ones on ebay i see. Best one https://www.ebay.com/itm/402659871481?epid=13002747220&hash=item5dc0660af9:g:7OoAAOxy3NBSlSvt

FCP or Rockauto (Both use Fedex). Sometimes shipping cost is very different for the same product so check out both. Rockauto has GST added iirc so FCP would win out one this one.

The 6 cylinder spring may not be much better depending on how much its lowered. Regardless of whether they work or not i wouldn't try it especially given the time it takes to do the job. Have you tried Weitz Industries. He had a 540i not long ago. Obviously those are but i dont recall the the actual springs being different in design. Most of the strut hardware appears to be the same too.

Probably but why would you bother to make a car handle bad

Nice writeup, but most here are savvy enough not to ever own this engine so you efforts maybe a bit in vain. Be prepare to play a game of wac-a-mole with the numerous other coolant fittings. Luckily you can do repairs as ive seen multiple people sink money into these and end up taking it out on the workshop.

Which 540i are you going to sell after you done with them?

Quality automotive tools don't really exist in hardware stores (NZ at least) mytools.co.nz Decent selection and prices on asian stuff (not far off trade in many a case) If you want European at a fair price then its Amazon or various international retailers around the globe. Primetools in Uk is good for facom if you specifically want them but shipping maybe a bit much in this case

You going need at least 2 wrenches to cover the typical ranges. A 3\8" ~20-100nm and a 1\2" ~70-350nm would cover just about everything. You could add in a 1\4" ~5-30nm if you wanted to get fussy on the low torque stuff. Toptul are one of the best quality options for the price. You could get a 3\8" and 1\2" in the above ranges for just over $400. Good support here in NZ also.