BMW E12 Questions...

I don't know much about them, but I do know they have a classic style that I seem to be attracted to, four doors, and a decent sized trunk. 

Besides the usual rust, mechanical issues, and the general diagnosis of being an old Euro hunk of metal with wires weaving about, anything I should look out for? I'm sort of hoping they are drop dead simple, but I could be wrong. This one is an 81' 528i. 

This wouldn't be a motorsporting car, just a weekend/weekday cruiser that looks good, sounds good, and can carry a toddler with some stuff for the park (bikes, etc.) with some ease.

Thanks in advance Team GRM. As they say, "enable me". 

I had a '75 530i. Drove it for 240K miles.  It had the worst a/c of any car i've ever owned.  I've owned bmw 2002s with better a/c.  If you overheat it you will probably crack the head. If driver's seat is badly worn you can swap driver seat for front passenger seat. 

Except for the shortcomings above, it was a great car for it's time. Easy to work on/maintain. Fun to drive, fast for the times, handled and stopped well and comfortable. I drove mine daily for 14 years and had very few problems and after 14 years the paint looked like crap but there was no rust. 

The 528i is an improvement over the 530i mentioned above; the latter has a thermal reactor that builds enormous heat right next to the cylinder head, while the former has a conventional catalytic converter that works far better and is located under the car. The M30 engine is pretty bulletproof as long as it's maintained. Some trim and interior parts may be getting hard to find, and will be expensive new if the are available. Suspension will probably need a complete refresh, but once done will make the car really nice to drive. As far as carrying bikes, you'll probably want a roof rack, as the shape of the trunk and opening for same are not especially good for that sort of thing, and the back seats don't fold.

Former E3 owner here. 

M30's of that era are known for cracked cylinder heads. A head from the 80's is the best solution, and there is a Spanish aftermarket solution that might be cheaper, and doesn't flow as well.  All  M30's have a thin steel tube valvetrain oiling rail that is held to the head by two hollow bolts.  The bolts frequently get loose and oil flows out around the resulting gap, and not on the rockers like it's supposed to, resulting in oil related failures.  Pull the valve cover and check for that, and make sure any valvetrain noise is just out of adjustment lifters. You can buy replacement bolts with thread locker pre-applied, and some people drill the bolts for safety wire. 

On my E3, the engine was tight in the engine bay, especially at the front and rear.  I bet E12's are the same.

The fuel injection is primitive.  Complete E28 top end swaps are possible, but do the research first.  On the stock FI, you can bolt-on swap the longer intake runners from a 320i to get more mid-range at the expense of a little top end. That works well with the 5 speed swap. 

All E12 manual trans cars are 4 speeds, except the last year, '81. Ratios are widely spaced, and I always felt 1st gear was too low but all BMW's from that era are like that, so you're stuck with it. E28 5 speeds will swap.  Avoid the 5 speed from an '85, they're weaker.  Or you can swap in taller rear gears.  Or you can live with as is. The E30 is perfectly happy to rev at 4K or more for as long as you'd like. 

E12's have horsehair seat padding, which deteriorates and will probably need to be replaced by now. 

As noted above, with a fresh suspension, they drive very nicely.  Diligent and lengthy searching may yield stiffer springs and bigger bars.  Bilstiens an Koni's should still be available. 

They rust a lot. The A/C is marginal. 

More parts are available than you'd think.  Some seem to go NLA and then become available again, so check periodically.  Parts are expensive. 

Visit firstfives.org and see if anyone still posts there. 

much love for the E12 here. Here's what I learned in 2 years (2014-2016):

Front struts are expensive, and my car needed them badly.

Fast idle / cold start assist comes from a very German valve that is NLA. I rigged a ball valve with a choke cable into the original plumbing and it worked good enough.

my car had a later M30B35 and 5-speed, but with the original 79 head for a compression bump, but also had the OE L-Jet (or was it K-Jet?) on it. Weird selection of parts but it ran good.

I rebuilt CV joints and forgot to torque the bolts, and dropped a halfshaft while taking GRMJoeG for a pre-cruise Woodward tour.

I ended up selling it on a whim and bought a 95 M3 a couple days later.

I don't want to be "that guy" ... but an E28 is a better all-around car. Easier to care for. Better parts availability. Better daily driver potential. Very similar looks: I bet most non-BMW geeks couldn't tell them apart. 

I'm guessing M2Pilot's 1975 530i kept the original fixed grill dashboard vents. They introduced moving vents on the 1976 cars so you could blow air towards you. A/C works fine on R12 if there are no leaks and it's gassed right. Blowing 42F on a 100F + Vegas trip on R12.

Yeah, visit www.firstfives.org it's still active. Great advice there.

E28s are getting troublesome as they age. Their double pivot front suspension, Motronic, Service Interval, ABS are stuff the e12 doesn't have, so no problems from that stuff.

So many of the problems seem to stem from rust and the BMW engine.  Avoid both by buying my rust-free, LS-swapped E28.  Kidding, but not really kidding . . .