All this is talk of older cheap cars (like original Beetles), of course.
You can’t build a truly cheap engine now because of emissions requirements. The tolerances required to keep emissions in check are extremely fine. And cheapo components might have okay tolerances out of the door but won’t stay that way for very long.
Emissions+collision safety killed the old Beetle.
Not true at all. Safety-wise, they obviously wouldn’t fly today but the Beetles weren’t any worse than the Japanese cars that replaced them in the 70’s. Emissions-wise, the Mexican Beetles were still able to pass the stringent emissions standards passed by Mexico City in the 90’s, which were comparable to the California ones, so they clearly could have hung on for a few more decades in the US at least.
What killed them in the US is simply that the Datsuns, Toyotas, and Hondas that came out in the 70’s were much better cars in most ways. Particularly in terms of them not requiring constant fiddling like the VW’s, but that’s less of an issue in countries with cheaper labor rates.
This was an import car speciality shop. The air cooled guys knew their stuff.
The problem is you have an engine that holds 3 quarts of oil, has no filter and when traveling at speed it won’t pick up the last quart and a half or so. On top of that the oil cooler sits right on top the #3 cylinder. In a vain attempt to keep #3 alive they modify the timing on #3 to lower the peak temps. This is why VW idle sounds so funny. They don’t idle even.
Bottom line is if you are a quart low on oil in 100 degree weather and hauling ass down the freeway you are about a half a quart of oil away from God.
Another interesting little gem about VWs. The carb inlet is brass pressed into aluminum. The inlet would rattle loose and gas would pour out. On most engines this isn’t a huge problem. Except VW who mounted the carb directly over the top of the generator which sparks as it turns. Can you say Kaboom?
The reason that VW succeeded both in the U.S. And South America wasn’t based on reliability, it was based on ease of repair and parts availability.
They blew up all the time, but the parts were on the shelf.
What the Op is describing is essentially a motorcycle with an enclosed cargo and passenger area, and these are pretty prevalent in third world countries, called a variety of names, “tuk tuks”, etc… Even then, they only exist in third world countries that don’t have any pretense of caring for air quality. As an example, most domestic Chinese carmakers are being driven more or less over the edge in the Chinese car market, because Chinese emissions regulations are at a point where many of their cars are essentially banned in larger Chinese cities.
Do you have cite for the timing being different on the #3 cylinder? How would that even be possible? The distributor caps terminals sure look like they’re all 90 degrees from each other, and the valve timing can’t be different (if that’s what you mean) because the valves on both sides run off a single 4-lobe camshaft. Cooling on the #3 cylinder was definitely an issue (the #3 exhaust valve was usually the one that would get burned out if you didn’t do the valve adjustments) but the “rough idle” was mostly just the boxer burble exhaust sound.
I certainly wouldn’t argue the VW was more dependable than the contemporary American land barges of the day, but it was significantly better than any other small cheap cars of the day. VW did have a good dealer network, but they were able to build it because their product was solid unlike most of the other also-ran pre-70’s imports. The reason why there were parts available all over the world was because they were popular cars, not the other way around.
I don’t think the ignition timing could or needed to be different on a VW flat four, but the cam/valve timings might have been different. Since *Rick *has been at pains to correct my postings by the odd tenth of a volt here and there, I’ll give him the benefit of the doubt… but I will say that I’ve never heard this before (even with a sister who was a master veedub mechanic) and can’t find any cite (including performance cam angles) that bear it up. 
(very small detail… that should be **Rick **up there, not Rick, which looks like some kind of taunt)
The valve timing can’t be different because it only had a 4 lobe camshaft driving 8 valves. The same lobes that runs the #3 valves also runs the #1 valves.
I think the only way you could make the ignition timing different for one cylinder on an old points n’ distributor system is to have one of the terminals on the distributor cap slightly off. It could be that the #3 terminal is slightly off on a VW distributor cap and I just never noticed.
Oh.
Not having any flat-four 'sperience, myself… I knew the VW engines were about as simple as things can get, but that’s a new… simpler.
Not the valve timing the ignition timing. To alter that all you have to do not put all 4 distributor cam lobes not equal distance apart.
So instead of 90-90-90-90 you have 90-85-95-90
It shows up clearly on an ignition oscilloscope.
A distributor for a 140 series Volvo ran about $120 back in the day. A 009 distributor for a bug with an identical body, and took the same distributor cap was $29. The only problem was your Volvo idled funny with a 009 installed.
Mind blown here as well. This is a fascinating thread.
I’ll take a guess at the question in the OP: Probably just as cheap/easy to build a good car to start with. 
I miss my '68. Keep in mind that these engines didn’t have an oil filter, which certainly impacted the change interval.