Unbreakable engines & boxes - or the complete opposite

I'm biased, but any MB build between 1980 and 1992.

you didn't ask about rust, did you?

Ford iron head 4.1 litre OHV crossflow as fitted to Ford Falcon XC and some Australian built Cortinas. Best Ford six ever as far as simplicity and reliability go. These came with a manual gearbox or a Borg Warner automatic. Avoid the later aluminium head OHV six as fitted to XD - XF Falcons, especially the first couple of years production, as there were quality issues. Availability may be an issue in Europe and they do hog the juice a bit. I dailied an XC wagon for about three years and it was getting a fairly consistent 22 mpg.

Audi straight 5 diesels run a long time (the petrol versions are pretty tough too). The 01e series of gearboxes that goes with them. The whole C4 A6 you'll find them in.

Any of the 1.6 or 1.8 8v VAG engines. The transverse gearboxes they come with..... not so much.

Nick

Falls outside of your time frame but indestructible engine and gearbox combo would be a Chevrolet LS engine teamed with an 4L80 transmission.

Easy 600K miles on the engine, and the same with the gearbox.

Anything that can take 1000hp with a stock bottom end will easily hold up to the 300-400 they come with stock

Easy swap into the chassis of your choice.

Stock they get an easy 22-25 on a run and with a manual that goes up to over 30.

P.

It depends what you mean. Any car will eventually die if you leave the oil etc.

As for bombproof cars:

-Mercedes OM60x engines, with the 4 pot and the 5 pot (601 & 602 engines) being the toughest ; they are a little more resilient to overheating.
-Ford OHVs as said.

If you can live with changing brake calipers potentially every 20k on the rear a Mk3 Mondeo with either a 1.8 or a 2.0 will fit the bill. We've done the following with each. All ran on LPG

-2001 2.0 Ghia X : 380k with the engine not being taken apart. Amazingly only one brake caliper. Albeit a gearbox in that time too.
-2003 2.0 Ghia X ; 200k with it having a rebuilt head at 170k ; It burned the valves out and had no Flashlube
-2007 1.8 LX : 325k. That had a head as well at 210k despite having Flashlube and it had a DMF and clutch at 300k. Before that it also had 2 rear brake callipers. It was a good car.
-2005 3.0 V6 Ghia X : 262k (got written off) rear caliper and a clutch at 212k. We did however change a number of cooling bits either when they looked like they were going or they had gone. The V6s aren't an engine you can drive on in the red without dire consequences. You can ask how I know... . Keep on top of the cooling however and they are very solid lumps despite what others say about HGs (I suspect they are down to people driving on them with cooling issues, using the wrong coolant and generally neglecting them).

I do wonder with the last two 2.0 and 1.8 cars whether shimming the valves correctly every 100k would have stopped the VSR despite running LPG. I only didn't do it because my garage said "There's no point". Ford however, claim they do need shimming every 100k. I did near double that before I had signs of VSR.

I'd have bought one over the Mercedes if I didn't fancy a W124 and if the insurance was cheaper.

B204/B234 - Bullet proof, can take good power and very easy/cheap to push them past 300bhp.

6G72 - I have the SOHC in my mk1 and they're very strong/reliable.

Chevy LS - As above but they've been jumped on with scene tax now.

Ok not as big and fancy as those above but any Vauxhall/Opel 8 valve family 1&2 engine from the 80s/90s, simple and cheap to fix, big miles as long as you keep on top of basic servicing and pretty simple to tune if you want a bit more BHP

For me has to be the 130BHP Pumpe Duese TDI engine. Had a few of them now and seen a good few over 500k miles if looked after. The older the get, the nicer they drive. Lowest mileage one has been 160k miles, highest 230k and all have been brilliant solid units and give a steadfast 45+MPG no matter what and have often seen 60+ on a run. As long as you use the correct oil and change the coolant every 2 years, never had a single engine problem.

I've got the 150, which is the same engine with a different map, in a 2003 Leon. Over the seven years or so I've had it it's needed a new camshaft and lifters (never seen a lobe worn off a cam before!), new injector wiring loom and numerous bits of pipe. They're quite fussy on oil. It's on 180k now and most problems I had were about 120k; the cam issue _may_ have been caused by someone putting in non spec oil in the dim and distant past, but that's speculation.

They're not bad lumps but they need to be looked after

The most reliable I've had is probably the 1.6 zetec-s I had in a MK1 focus, considering how much I mistreated it at the time. Saying that it did like to munch through coil packs!