Abandoned History: Cadillac's Northstar V8, Head Bolts and Gaskets Aplenty (Part I)

Back in 2022 Abandoned History covered the development and usage of Cadillac’s all-star engine for the Eighties, the High Technology V8. As the 4.1-liter pile showed promptly that it was terrible, General Motors massaged, improved, and enlarged it into the HT4500 and finally the (not HT) 4.9-liter. But by the time the 4.9 arrived, the engine was already at the end of its service life. The General had an all-new, much better V8 that would trounce the 4.9 and bring Cadillac back into the luxury fray: Northstar.

The decades leading to Northstar deserve some context. The Seventies and Eighties were not kind to the domestic luxury manufacturers, namely Cadillac and Lincoln (Chrysler ceased to be a luxury car maker after the full-size C-bodies of 1978.) The latter part of the Seventies ushered in downsizing subsequent to the 1973 OPEC embargo and emissions regulation. Luxury buyers wanted neither downsizing nor smog-strangled engines. 

General Motors veered left with its downsized B-body full-size cars in 1977, while Lincoln went right and maintained its true full-size cars through 1979. All the while, domestic manufacturers struggled to produce successful smaller cars in the wake of the arrival of efficient and reliable Japanese compacts from Honda, Toyota, and Datsun in the early Seventies. AMC was arguably the best purveyor of compact domestic cars, but the folks in Kenosha just didn’t have the market share of the other Big Three.

Further downsizing in the Eighties occurred (courtesy of a predicted fuel price spike that didn’t happen), when General Motors bet big on front-drive luxury from 1985 onward. Front- and rear-drive Eighties Cadillacs were fitted with the fairly awful aforementioned HT4100. All the while, Roger Smith was at the helm at General Motors. Smith sought to transform GM into a multi-arm conglomerate like General Electric, and invested billions in early satellite navigation, technology, and engineering companies. 

Smith and other top brass at GM were also obsessed with the idea of the “younger, affluent Euro-centric yuppie” car buyer, and how they could alter the company’s brands to net the sort of customer who’d buy a BMW or Mercedes-Benz. Oldsmobile gained its International Series trims and Touring models, Buick had T-Type, and Cadillac had Touring models like the Eldorado Touring and DeVille Touring. Of all GM brands, it was Cadillac who would chase the European car intender the longest (1985- ). 

Fueling the flames, new competition for the desirable younger and affluent luxury customer arrived via the likes of Acura in 1986 and Lexus and Infiniti in 1990. The Japanese luxury car was a new thing, and it offered greater technology than domestic (and German) cars with better build quality, at lower prices. In a single moment, the 1990 Lexus LS 400 arrived and made the domestic competition look like dinosaurs, no matter how much one may like the Town Car or Fleetwood.

It was in this era Cadillac saw its traditional customer base erode away (via death, largely), and attempted to walk the traditional-sporty line with products like the Eldorado ETC, STS, DTS, DHS, SLS, STS, and Catera. Traditional offerings like the Sedan DeVille paired with the DeVille Touring Sedan and attempted to capture both sides of the customer base. In practice, this didn’t work so well: Cadillac massively overestimated its appeal to the younger customer, while underestimating just how much the older customer wanted a traditional looking and feeling product. The elephant in the room all the while was a thing that kept many customers away from their Cadillac dealer, the reliability woes of the Northstar.

As the 4.5-liter V8 powered most Cadillacs down the road (weakly) General Motors started work on an all-new V8. Modern, lighter, more efficient, the new engine would use a dual overhead cam (DOHC) design, a stark contrast to the overhead valve (OHV) design of every GM engine built thus far. It’s reported the work on Northstar began as early as 1984, but seems more likely it was around 1987.

Change was in the wind within GM and at the competition. Cadillac knew Chevrolet was in development of a DOHC V8 with Lotus (the LT5 of 1997). Mainstream Japanese manufacturers were in development of the aforementioned luxury brands, while at the higher end Mercedes had its impressive 4.2, 5.0-liter, and other naturally aspirated V8s. And Lincoln was in development of its 32-valve DOHC V8 for the upcoming Mark VIII.

Naturally, GM turned to its most tech-forward engineering team to work on the Northstar: Oldsmobile. The preliminary ideas flowed in, and concentrated around saving money and the utilization of Cadillac’s existing HT 4.5 engine. One suggestion was to add a four-valve cylinder head onto the 4.5, and create a 32-valve that way. The idea suggested they could use DOHC or an OHV design. 

At that point, Chevrolet chimed in and mentioned how they’d already attempted to do this in the development of the LT5. Lotus engineers talked the Corvette team out of it and said it was not feasible for various reasons. Ultimately it was decided that to really make a mark and return Cadillac to its competitive glory, an all-new V8 was required. It was a different mission than the Corvette V8’s development, as Cadillac indicated such a powerful engine was not suitable for its luxury vehicles. Smoothness, lightness, and a balanced power delivery were all virtues Cadillac wanted to convey. 

Benchmarking occurred at Cadillac’s R&D, where engines from other manufacturers were purchased for evaluation. The team bought Mercedes and BMW V8s, and also sprung for examples from Ferrari and Lamborghini. The Italian power was more advanced, and used the desired DOHC and four valves per cylinder layout.

While the gleaming V8s were on display at the R&D office, the finer details of the Northstar needed to be determined. Beyond DOHC, four valves per cylinder, and a general list of desirable qualities, there were a lot of specifics still up in the air. We’ll pick up there next time

[Images: GM, BMW, Mercedes-Benz, AMC, seller]

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