Interference Engines--Why?

My grandfather had one of those, with an automatic.
I don’t think the tank was ever more than 1/2 full.
When I was a kid in the late '60s he’d buy $1 of gas and drive from Wash. DC to Garrisonville VA and back, 41 miles each way, to the weekend cabin.

That engine was 2.5L. Modern 4 bangers that large have balance shafts.

@circuitsmith. The Chevy II, introduced for the 1962 model year had rear single bar leaf springs. The Chevy II was brought to the market to compete directly with the Ford Falcon. The Ford Falcon with its conventional layout sold much better than the Corvair which was introduced the same year.

You should drive a 61 or 62 Pontiac Tempest with the 195 cu. In. 4. The engine was literally one bank of a 389 v8, and would shake you out of your seat.

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@old_mopar_guy. As I remember, the curved driveshaft also caused a vibration.
Cars back then were interesting. The Pontiac Tempest with the transaxle, the Buick Special with the V-6 engine, the Chevy ii with the 4 cylinder engine, the Corvair, the Saab and DKW with the two stroke engines gave car buyers a lot of different choices. None of these cars had interference engines.

And don’t forget the third member of the BOP compacts, the Olds F85 with a 215 cu. Inch V8 with aluminum block and heads. And in 62&63 Olds produced a turbocharged version called the Jetfire.

You did not like the Continental engines in the Kaisers and Frazers?

Actually, my very first car repair on a car was on a 47 Frazer with the Continental engine they all had. It was a head gasket and my stepfather told mem you blew it ,you fix it. After I got the head bolts off, I was afraid to pry hard enough to break it loose. He had been relaxing on the porch and when I appealed to him for help, he started the car and blew it off.

I remember that engine. It looked exactly like they took their V8 engine and sliced off four cylinders to make it an inline 4-cyl engine.

I didn’t drive one, but have to assume it wasn’t balanced at all.

International Harvester’s original Scout offered 2 4 cylinder engines that were half of their 304 and 390 V-8s. But who’s worried about a rough idling engine in a Scout?

It was a 3.1 liter (195 cid) 4 cylinder without balance shafts…so YES, it was imbalanced like every other 4 cylinder. Just worse. The bigger the 4 cylinder, the bigger the shake.

The all-aluminum 215 V8 in the Buick and Olds was sold to Rover and used in Brit cars for 40 years, it was that good.

It became the Buick V6 by cutting 2 cylinders cut off, sold to AMC, used in Jeeps until the mid 70’s when GM bought it back to use in the Monza based small, sporty cars sold in the 70s and 80s. Later it was refined through several generations of the GM 3.8 liter V6. That V6 soldiered on for over 40 years as well.

My Chevy Luv (Isuzu) had a 4-cylinder with a balancing shaft. Actually was a lot smoother then many other 4-cylinders.

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@Mustangman. I thought the V-6 in the Buick Special that came along in 1962 was a cast iron block that was made by lopping two cylinders off the nailhead V-8.

From what I can find it was actually based on a cast iron version of the 215 V8, with two cylinders lopped off. They later modified the crankshaft to give each piston its own journal, evening out the power pulses.

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@texases. You are probably correct. I do remember that the Buick V6 in the Special was a cast iron block and the V8 was an aluminium block.

@texases has it right. It was a cast iron version of the 215 V8 with 2 cylinder cut off. The 90 degree vee made for a bit of a rough engine.

The “even fire” version with offset crankpins came out about 1980 and later a balance shaft was installed in the vee to smooth it further since it was in most of GMs fwd luxury cars from the mid 80s on.