AHC: American Inline Six Engines More Widespread Post-1970s

Delta Force · Mar 25, 2016

At one point the inline six was the quintessential American automobile engine. In fact, the Chevrolet inline six was the only engine used by that marque between 1929 and 1954, when the Chevrolet small block V8 began to supplement it. Inline six engines even powered the first production years of the Chevrolet Corvette and were the standard engine option on several muscle cars. Sometime in the 1960s and 1970s the inline six began to fall out of favor for American vehicles, especially cars.

Could the inline six have remained popular through to the present, especially on cars? Maybe the heads and other equipment could be twinned to create V12 engines to compete directly with the European luxury brands and make both accountants and engineers happy?

Dathi THorfinnsson · Mar 25, 2016

Once cars started shrinking as they did after the Oil Shock, the automakers didn't want to have as long a hood as would be required for an inline 6, as I understand it. V6s and V8s were much more space efficient.

I don't think twinning an inline 6 would make a V12 that much easier than expanding a V8 - but I could be wrong. I'm not a car geek.

Just Leo · Mar 25, 2016

The fall from favor might have been influenced by Alec Issigonis and his pesky transverse engine FWD Mini.

marathag · Mar 25, 2016

The real problem was that with the exit of Hudson, there were no more high performance inline 6s, so they were left with the rep of boring, gas sipping base engines during the HorsePower Wars.

Admiral Beez · Mar 25, 2016

Dathi THorfinnsson said:
Once cars started shrinking as they did after the Oil Shock, the automakers didn't want to have as long a hood as would be required for an inline 6, as I understand it. V6s and V8s were much more space efficient.

American inline 6 engines were used in compact cars well into the 1980s. AMC's straight 6 ran from 1964 to 2006, https://en.wikipedia.org/wiki/AMC_straight-6_engine My mother in law had a 1983 Concord with straight 6 engine. This same engine was in the Pacer subcompact - so inline engines can work on "smaller" cars.

The Chevy straight six ran from 1929 to 2009 https://en.wikipedia.org/wiki/Chevrolet_straight-6_engine

Ford's straight six ran into well into the 1990s, https://en.wikipedia.org/wiki/Ford_Straight-6_engine

Just Leo · Mar 25, 2016

Admiral Beez said:
This same engine was in the Pacer subcompact -

The AMC Gremlin was arguably AMC's sub-compact. It was the ridiculous looking small car with the long front and no rear.

The Pacer was in the same issue of "Consumers' Report" magazine as the VW Rabbit, way back when, and the VW shone in every performance detail by comparison. I saved myself a fortune in Windex, but there's more to it than that.

Admiral Beez · Mar 26, 2016

Here's a good article advocating for the revival of the inline 6.

http://www.roadandtrack.com/new-cars/videos/a8645/the-enginerdy-dept-straight-six-revival/

You can avoid the drama by arranging the pistons in one line. A straight-six doesn't need split crankpins, balance shafts, or big counterweights, because each of its cylinders has a twin that's doing the opposite thing, at the same time and in the same plane, canceling out the other's forces. That lack of internal dissonance gives the same perfect balance as a V12. There's a reason museum-piece marques like Rolls-Royce, Mercedes-Benz, Jaguar, Aston Martin, and Alfa Romeo earned their reputations with inline-sixes.

BMW today uses straight 6 engines in its smaller cars, like the 3 series. Jaguar used its famous XK straight 6 until the 1990s, when it was replaced by a Ford V-6.

Driftless · Mar 26, 2016

Admiral Beez said:
This same engine was in the Pacer subcompact - so inline engines can work on "smaller" cars.

Just Leo said:
The Pacer was in the same issue of "Consumers' Report" magazine as the VW Rabbit, way back when, and the VW shone in every performance detail by comparison. I saved myself a fortune in Windex, but there's more to it than that.

I confess to owning a 75 Pacer for several years (with the 258 c.i.d engine & 3 speed manual trannie). I really liked the car, even though was bit of a dog on performance. Indifferent acceleration and gas mileage. My friends alternatively mocked me for driving a "rolling greenhouse" or "The Punkin" for it's color. I ultimately traded the Pacer in on a new Chevy Citation with the transverse V-6...... That was a very costly mistake....

tomo pauk · Mar 26, 2016

Admiral Beez said:
Here's a good article advocating for the revival of the inline 6.

http://www.roadandtrack.com/new-cars/videos/a8645/the-enginerdy-dept-straight-six-revival/

BMW today uses straight 6 engines in its smaller cars, like the 3 series. Jaguar used its famous XK straight 6 until the 1990s, when it was replaced by a Ford V-6.

BMW used the straight six in the 3 series some 30 years ago, the cars being far smaller than today's.

Admiral Beez · Mar 26, 2016

tomo pauk said:
BMW used the straight six in the 3 series some 30 years ago, the cars being far smaller than today's.

True. straight six engines have powered many tiny cars (and not just two seater roadsters), including most of the non-4 pot cars made in Britain throughout the 1950s on to the industry's collapse in the 1970s, such as the:

Triumph Vitesse https://en.wikipedia.org/wiki/Triumph_I6

Various BMC cars, including the Austin Westminster https://en.wikipedia.org/wiki/BMC_C-Series_engine

And then there's all of Bristol's fantastic cars that predate the Chrysler V-8, such as the 406 below.

Definitely a straight six can fit into today's cars. Especially with today's designs with the super long noses, presumably for crash protection. Check out the new Mazda CX3. You could likely fit a straight 8 in that engine bay.

Behemoth · Mar 26, 2016

The AMC straight 6 that was used in Jeeps was pretty good as far as durability from what I recall. A friend of mine mentioned that a relative of his did some testing on Mitsubishi engines a few years ago and for laughs decided to bring in a straight 6 from a Jeep. I don't recall the name of the chemical/product that he used (used to seize an engine) but he dumped it into both of the engines. The Mitsubishi engine didn't last too long but the Jeep engine lasted roughly three hours before it finally locked up and died.

Carl Schwamberger · Mar 26, 2016

Just Leo said:
The AMC Gremlin was arguably AMC's sub-compact. It was the ridiculous looking small car with the long front and no rear.

...

IIRC the Gremlin was a Hornet with the trunk chopped off.

marathag · Mar 26, 2016

Carl Schwamberger said:
IIRC the Gremlin was a Hornet with the trunk chopped off.

The Pacer was the smallest car that could be made with the tooling from the Ambassador production line that was idled after the 74 model year

Driftless · Mar 26, 2016

Carl Schwamberger said:
IIRC the Gremlin was a Hornet with the trunk chopped off.

Kinda looks that way doesn't it, though the Hornet's wheel base was a bit longer

That is an ugly car..... And I owned (and liked) both my AMC Pacer and Hornet.

MonaroLS · Mar 26, 2016

Ford in Australia still use a modified version of The US Ford straight six. It is now twin OHC and very potent. Unfortunately when they shut down manufacturing this year, that motor will be gone

Driftless · Mar 26, 2016

GM was using inline five cylinder engines as an option for several vehicles from the 90's until recently. Why not go to the six?

Driftless · Mar 26, 2016

MonaroLS said:
Ford in Australia still use a modified version of The US Ford straight six. It is now twin OHC and very potent. Unfortunately when they shut down manufacturing this year, that motor will be gone

The Ford Barra family of engines? What's the reasoning for discontinuing production?

MonaroLS · Mar 26, 2016

Driftless said:
The Ford Barra family of engines? What's the reasoning for discontinuing production?

Without going into the politics of it all (which makes me really rant), it has become uneconomical to manufacture cars here in Oz. Ford shuts down later this year, GM and Toyota next year (Mitsubishi already gone a few years ago).

Driftless · Mar 26, 2016

MonaroLS said:
Ford in Australia still use a modified version of The US Ford straight six. It is now twin OHC and very potent. Unfortunately when they shut down manufacturing this year, that motor will be gone

Driftless said:
The Ford Barra family of engines? What's the reasoning for discontinuing production?

MonaroLS said:
Without going into the politics of it all (which makes me really rant), it has become uneconomical to manufacture cars here in Oz. Ford shuts down later this year, GM and Toyota next year (Mitsubishi already gone a few years ago).

I just did a little interweb poking and the Barra engines seem to have quite a few fans for both performance and reliability. That is a damn shame that the production is being wrapped up

Driftless · Mar 26, 2016

To connect back to the OP, that Australian Ford Barra family of engines originated with a US Ford design from the 50's. The Australians made it a much better engine.