Design difference between 4cyl engines from America vs Japan

The 2.0 duratec in my Transit Connect has been a good engine but not refined as the Honda 1.5 or the Jetta 1.4 or the Audi 2.0.
180k miles on it and I've done 1 set of plugs at 100k and a valve cover gasket at 160k, pic @160k below
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. Thats it.
 
When I was shopping for a commuter I opted for the Escape with the 2.5 as it is a proven engine with a great track record. So far so good. I just turned over 100k miles with no issues.
Yeah, my Ford 2.5 is still perfectly fine no matter how hard I beat on it haha.
 
My 90 turbo eclipses 2.0 was a gem,

stock the car ran about as hard as a buddys 77 928- the whole group of friends could hardly believe it and were immediately impressed.

Leaned on with a bunch of HKS goodies it was a little monster

First car I ran 100% synthetic in, and actually never changed the sump, I dumped the filter and replaced whatever came out every 3K (wouldnt do that again today) - beat the tar out of it and sold it with Zero problems.
 
American and Japanese 4 cylinder engines are very similar to the point it's hard to pick them apart. Modern 4 cylinders are pretty much all aluminum, DOHC, timing chain driven, and have features like variable valve timing, plastic intake manifolds, etc. A Honda K24 is pretty similar to a Chrysler World Engine/TigerShark 2.4L or an GM Ecotec 2.4L. The newer engines are generally smaller and turbo charged, but again a Honda K20 Turbo is pretty similar to a Ecotec 2.0L Turbo. It's certainly no longer like in the 90's where GM was selling old all iron pushrod boat anchors like the Iron Duke or the 122 against much more modern and refined 4 cylinders like Honda's F22.
 
American car engines are loose, imagine shooting pool with a rope. Or throwing a hotdog down a hallway. That’s the compression.
I’ve certainly heard things like this said before. But is there any actual evidence of this?
 
I’ve certainly heard things like this said before. But is there any actual evidence of this?
I’ve heard it too, but seeing some shop manuals and whatnot they’re held to as tight of tolerances as anything else… at least for anything made in the last 25-30
years.

For instance, the 2003-2008 5.7 HEMI (I know this is about 4 cylinders, but this info is kind of hard to find not buried behind a paywall) has the loosest tolerance of +/-0.0005” on the main bearing and connecting rod journals, from what I can find. Taper is 0.0001” max, out of round is 0.0002”. Can’t really get much tighter in a high volume production environment, but also not hard to hold assuming you have decent machines and tooling. For reference, a piece of printer paper is ~0.003 thick. Cut that into 3 equal pieces, then cut one of those pieces 10 more times equally.
 
There was a huge difference in quality between my first car vs. my high school girlfriend's first car. 1978 Chevy Monza 2.5 vs. 1978 Civic. The little engine in her car was very smooth and refined, felt well-balanced, and this was after it had taken abuse and neglect from both her brothers before being handed down to her. I don't recall her having a single problem with that car the entire time she had it.

The Iron Duke in my car was brash, noisy, rough, and hated to rev. Every gasket leaked, and things were always breaking.

I really think Cujet's post hit it on the head. Compared with the Civic, the Monza was just a rough-around-the-edges beast that needed a couple of years in finishing school to be on par with that Honda. Their engines had better balance, loved to rev, and didn't vibrate all the screws out of the car while doing it. This contributes to their famously reliable engines of that era.
 
Cujet explained well.
Some 20yrs ago I read an article (in print of course) where former Opel no.1 explained how GM ran Opel into the ground. It is basically opposite of what Cujet wrote. And worse thing is that Opel had a lot of remarkable engines, but accountants ran further evolution of those engines into the ground mostly by choosing sketchy suppliers that delivered poor quality.
I think key issue here is cultural. It is not like the US suppliers cannot deliver top notch quality. Japanese and European manufacturers use a lot of US suppliers.
But, In the US leadership in these companies is under pressure to deliver fast results. Stakeholders want immediate results and those results are usually possible only by cutting cost. In Japan and Europe they are more focused on long term viability. It is not about short term profits but long term stability. Also, in many of these companies engineers are one running them not guys with MBA. I remember when VW board recommended guy who was not engineer to run VW, and Angela Markel had to voice her opinion too considering heat they were getting from press, unions etc. here Ford was run I think few years back by a guy who was furniture salesman.
 
American car engines are loose, imagine shooting pool with a rope. Or throwing a hotdog down a hallway. That’s the compression.
Loose in what respect? The low compression days were the 70's and 80's and that was for smog, compression ratios have gone up significantly since then, my 6.4L is 10.9:1, the 5.7L 10.5:1.

Even in the 1980's, the 302HO engines were hand assembled using balanced components and up until the hypereutectic slugs were fitted for emissions, had TRW forged pistons.
 
The 2.0 duratec in my Transit Connect has been a good engine but not refined as the Honda 1.5 or the Jetta 1.4 or the Audi 2.0.
180k miles on it and I've done 1 set of plugs at 100k and a valve cover gasket at 160k, pic @160k below

The Ford 2.0L Duratec is in fact a Japanese engine as it's just a Mazda L engine from the era when Ford owned a portion of Mazda. Their engine partnership went the other way too, Mazda used the Ford designed Duratec 3.0L V6's and the later Cyclone V6's that replaced them.
 
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