a. Chevy Vega. From what I have been told, the aluminum block engines warp. From what I have seen, they start rusting almost immediately.
b. Ford Pinto. Seriously underpowered, even compared to other crappy cars of the era. Oh, and they can reportedly explode under not-so-unusual conditions.
ETA: honorable mention to the car Mrs. Raza brought to the marriage: Hyundai Excel, circa 1989 model. Three cylinder engine was so slow that I seriously couldn’t believe it was legal to sell a car in the US that was that underpowered.
I had a CHevy Vega with the aluminum block. GM brought out the Vega and it immediately rusted around the wipers and in a circle around the fenders. GM made the later models with a Zinc-chome metal coating that took care of the rust problem. So I bought one.
The engine went bad. I took it is for a oil change and the gas station pointed out the block cracked and oil and anti-freeze were mixing creating a tar like substance. I barely got it to the dealer. They kept it for over 6 weeks working on it. I was told they had subcontracted a shop to build new heads out of steel. They were so busy that I had too wait a long time.
Then a shock tower broke through causing a terrible rattle. I had to find a welding shop to weld it back so the shocks could be screwed down.
It was a terrible car. When the shock tower broke, GM said it was due to driver abuse and not covered. It was a 4 cylinder wagon. I did not drive it hard nor off road with it. It was not my fault.
I shopped for a Yugo once. That was an experience. The salesman went out to the lot to pick one for my test drive, and the one he brought wouldn’t start again when I turned the key. He had to go get a second Yugo – and he chose to leave that one running. I noticed greenish fluid pouring – not dripping, pouring – out of the tailpipe as it ran, and asked him “what is that?” “I don’t know,” he said, miserably.
the funny thing about the Vega is that it was GM’s first car that went through a total-body anti-corrosion dip. 'cept the problem was that back in '73 they still didn’t always have proper drainage and access holes in the sheetmetal, so the primer didn’t make its way into all of the little nooks and crannies in the structure. Which- not coincidentally- are the same areas where water and road salt/grime would collect and sit. Bam! insta-rust.
and the problem with the aluminum engine was not really the engine itself, but the hilariously undersized cooling system. it was stupid easy to cause the car to overheat, and when that happened the open-deck block warped.
the liner-less aluminum block is actually quite similar to the process that Benz and Porsche used about 20 years later.
My 76’ Vega was bullet proof for 14 years. The engine and automatic trans never faltered. I drove it to the junkyard because of lack of integrity of the body itself. When I would step on the brake, the steering wheel would tilt up because the whole body was bending.
I don’t recall severe rusting or engine problems with mine. What I had trouble with was starting it (it would not start with a key from the inside, repair was too costly for me at the time so for quite awhile I’d have to open the hood and short two terminals with a screwdriver. That got old pretty quickly).
Years later I read that Dave Barry (the humor columnist) had the exact same problem (and solution) with his Vega.
Of my later ventures with subcompacts, the next worst was the Dodge Omni, which kept mechanics busy with a series of problems, plus it was unstable on turns.
I had an AMC Gremlin. One day I had the hood open. When I went to close it, I reached up, grabbed it, and pulled. Instead of closing, it bent. The back part did not move at all, the front part came down and the hood bent in the middle.
When I told my mechanic he said “yeah, they’re known for that”.