M20 lifespan and maintenance?

[bimmerteck]

My first e30(1984 325e) had 494k on it when it was t-boned. Independent maintained from day one and running like a top. I sold the car to a technician buddy who lightly rebuilt the motor and put it in his e28, and last I heard it was still going strong though it's rarely driven now.

[Vincent Brick]

Close to 250k here, slightly low but even compression across all cylinders, resealed it along with new timing belt and full cooling system refresh 18 mos ago, and I too tend to beat the piss out of it (but only when its warmed up, no cold-start hoonin'). I see no reason it won't last beyond 300k miles and my driveway stays bone dry.

[BaltimoreBimmer]

I've only had my e30 for a few months now and haven't really driven it much. Parked it out back to wrench on and drive on the weekends. It's nice because I can fit my whole body under the front end without jacking it up whatsoever as long as I take off the front spoiler and bumper.

Anyway, I was poking around a few days ago preparing for my initial overhaul (timing belt + therm, WP, a PS hose, some other bits, and all the front end seals) when I noticed what looks like a solid buildup of sludge on the side near the head gasket.... Not excited about that but oh well. 220k on the odo and supposedly one PO.... I did get this to scratch my wrenching itch so it may well work out lol.

[Stapes]

Mine is an '86 325e M20B27 with 246K miles on it. No maintenance records from the PO. I started with suspension rebuilt, hoses, head and oil pan gasket. However, the "while I'm there + OCD" got the best of me and ended up taking my head and short block to Autosport for a machine shop job.

It had 150-160 compression on all but #1 and 2, which turned out to be the intake 1 and exhaust 2 valves leaking, the culprit. Rockers are gone, cam will be reground and new exhaust valve guides will be added.

All cylinders had the original crosshatching marks and I found all crankshaft bearings worn nicely and evenly. My machinist said that everything (pistons, crank, cylinder, and head) was within original spec's.

I think there was no reason why this engine should had need a full rebuilt if proper maintenance was done. I'm also spending a lot of money on mine, but I'm keeping this car for the long run so I'm glad I'm doing this now.

[cheffy30]

According to a retired BMW M20 engineer I talked to some years ago, the M20 is a 500,000 km (312k miles) design that shouldn't need to be opened for service until 500,000 km, if even then, if it is well maintained. However, he was quick to add that this level of service is typically only obtained in Germany, where the average owner has maintenance performed regularly. Americans don't take care of maintenance routines as they should, based on his examination. I would have to say he is correct, based on my own personal experience with working on/inspecting many E28 528e vehicles, during the past 25 years. They are in poor mechanical condition due to poor maintenance... but many M20s continue to provide service, inspite of their actual mechanical condition and abuse.
FWIW,
-Rod

mine has 241k. it purrs. no leaks. i maintain it regularly with passion. i drive it hard. i am sure it will see 350k... then my son will get it... maintenance and lubrication is the key to everything that has moving parts.