But will it last?
Been reading a ll t he raves about the new MercedesAMG A45 engine; ver y impressive specs, but watching a v ideo of the assembly, it appears to have only t wo-bolt mains. I don’t k now if t his is normal for four-pots as I prefer play ing wit h eights of t he V variet y. (My GTS-R has just ticked over 6000km after t wo years).
But do you reckon this new high-tech wonder will sur v ive t he boost and 9:1 compression? I k now the tech is amazing, but will t hese high-stress units last t he distance?
Paul Hamilton, Email
THIS HAS been an ongoing discussion among tappet-heads, Paul. There’s certainly a large proportion of UC readers that have their doubts over the long-term prospects of new engine designs. But I guess you’d expect that from us old codgers who reckon milk doesn’t taste like milk any more, kids have no respect and the sky was bluer in the old days. Nostalgia ain’t what it used to be, if you know what I mean.
Personally, I’m kind of with the too-strong-isbarely-strong-enough mob. I love things that are over-engineered and one of the things I really like about the LS1 V8 in the MBC tow-pig is the fact that is has six-bolt (count ‘em) main bearings. And that’s in a relatively low-stress big-inch engine that doesn’t rev beyond 5500rpm and isn’t tuned to make 200-horsepower per litre.
However, you can’t ignore the fact that modern engines are capable of some really amazing feats in terms of their output and hanging together while they’re at it. I guess the wild-card in a lot of this is forced induction which places huge stresses on everything it touches. Modern turbo-motors not only use higher-thanever boost pressures
(by production-engine standards) they also do it with high static compression ratios.
By and large, though, I think modern engines are stronger and more long-lived than their grand-daddies, provided you don’t start asking too much of them in terms of boost, compression and specific output. Think back to the old Holden grey motor and the Pommy stuff (a lot of it side-valve) around at the same time. Those engines routinely needed a valve-grind and de-coke every 10,000 miles or so and even the Holden grey (known at the time for being a tough customer) generally needed rings and bearings at about 60,000 miles. I reckon the view of many people that an engine is worn out at the 100,000km mark is a hang-over of these days. It’s a trap that many fall into, then elect to sell perfectly good
cars to people like me for chump-change because they think the (not-very) old girl is getting worn out.
Meantime, I don’t recall anybody mentioning that their Honda Civic needed an overhaul at the same point on the odometer. And more modern locally-made cars seem to go forever if they’ve been serviced correctly. The secret is surely in design, manufacturing accuracy and improvements in metallurgy over the years. Stuff is just better these days; tolerances are tighter, and the materials superior. So it lasts longer and goes further.
However, as you point out, Paul, there are always the wild-cards like the highly-strung AMG two-litre you’ve used as your example. Frankly, while I don’t think it’ll be a hand-grenade as such, I doubt whether I’d be taking a punt on a second-hand one with, say, 200,000km or so on board. The stresses involved in such a powerplant are immense and that simply has to take a toll on the wearing bits inside. The chemistry may have improved, but you can’t get around physics.
That said, there are always other standouts, too. The original Mazda MX-5 with its little 1600cc engine that showed about 3200rpm at 100km/h in top and revved like a banshee, is still capable of 400,000km or so before most people lift the head for a look-see. But then you discover that this engine was designed to be turbocharged but was sold in the wee roadster in atmo form. Ah-ha!
Also, my own experience of a lot of European engineering is that it doesn’t appreciate Australian heat cycles. Many Euro-brands, for instance, have found that their machinery – which never gave an ounce of trouble on the Continent – suddenly croaks early when you expose it to Aussie ambient temps and usage patterns. Cylinder heads seem the main culprit, but even the plastic used in some of the cooling-system plumbing can die an early death out here.
Then there’s the question of culture and how long people in various parts of the world expect an engine to last. For us, it’s black arm-bands if an engine drops its guts before a quarter of a million kays have passed under its wheels, but in other places, that’s not the case. When early versions of the Chev LS1 V8 (six-bolt mains regardless) started burning oil, for instance, Holden in Australia was forced by a mob of angry owners on the war-path to replace a bunch of mills under warranty. But in the US where the same engine was burning the same oil, punters tended to just top them up between services and not complain. Because the car is much more of
a disposable item in the States, so folks just figured they’d put up with this until they traded-in in a few months.
As an aside, I’m currently on the trail of an ex-taxi that has apparently clocked up a million kliks. I’ve been in touch with the owner, who’s agreed to let me drive it and see for myself what a million kays does to a Ford Fairlane. Stay tuned.