Cadillac High Technology engine

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Cadillac High Technology engine
Cadillac 4100 V8 engine in Eldorado.jpg
Overview
Manufacturer Cadillac
Production 1982-1995
Layout
Configuration V8
Displacement
  • 4,087 cc (249 cu in)
  • 4,467 cc (273 cu in)
  • 4,893 cc (299 cu in)
Cylinder bore
  • 88.0 mm (3.465 in)
  • 92.0 mm (3.622 in)
Piston stroke
  • 84.0 mm (3.307 in)
  • 92.0 mm (3.622 in)
Cylinder block alloy Aluminum
Cylinder head alloy Cast iron
Valvetrain Overhead valve
Compression ratio 9.5:1
Combustion
Fuel system
Fuel type Gasoline
Oil system Wet sump
Cooling system Water-cooled
Output
Power output
  • 135 hp (101 kW) (4.1L)
  • 155 hp (116 kW) (TBI 4.5L)
  • 170 hp (130 kW) (Allante 4.1L)
  • 180 hp (130 kW) (PFI 4.5L)
  • 200 hp (150 kW)(4.9L & Allante 4.5L)
Torque output
  • 190 lb⋅ft (260 N⋅m) ( 4.1L)
  • 235 lb⋅ft (319 N⋅m) (Allante 4.1L)
  • 245 lb⋅ft (332 N⋅m) (4.5L)
  • 270 lb⋅ft (370 N⋅m) (Allante 4.5L)
  • 275 lb⋅ft (373 N⋅m) ( 4.9L)
Chronology
Predecessor Cadillac V8-6-4 engine
Successor Cadillac Northstar engine

The Cadillac High Technology Engine was a V8 engine produced by the Cadillac division of General Motors from 1982 to 1995.

While the High Technology engine was being developed, due to higher Corporate Average Fuel Economy standards being phased in by the United States government, Cadillac introduced a variant of their traditional V8 engine with the first usage of cylinder deactivation for 1981 as a stopgap measure to increase the fuel economy of their lineup.

However, the V8-6-4 engine would experience a litany of unsolvable problems in drivability and reliability mostly due to the primitive state of engine control technologies at the time. Cadillac was then forced to rush development and production of the High Technology engine for a 1982 introduction in their current rear-wheel drive models.[1]

This would be the last engine family exclusive to the Cadillac division because its successor, the Northstar, would go on to share its architecture with the Oldsmobile Aurora in 1994 and later with flagship Pontiac and Buick models, such as the Pontiac Bonneville and Buick Lucerne. Currently, Cadillac V8 models use the GM small-block engine, which is commonly identified with the Chevrolet division.

HT-4100[edit]

Cadillac 4.1 L engine

A new lighter V8 engine was rushed into production for 1982, the HT-4100 (option code LT8). It was a 4100 cc V8, designed for rear-wheel-drive and longitudinal front-wheel-drive applications sharing the same "Metric" transmission bellhousing pattern as Buick, Oldsmobile, and Pontiac rear- and front-wheel drivetrains for 2.5 L 4-cylinder and 2.8, 3.1, and 3.3 L V6. A new line of downsized Cadillac cars with the transverse mounted V8 engine was slated for 1983. However, delays in the downsizing program shared with Buick and Oldsmobile postponed the introduction of those models until 1985.

Design Features[edit]

HT stood for High Technology. For its time, the engine and its electronic control module (ECM) were quite sophisticated, despite having a throttle-body fuel injection system (as opposed to more advanced multiport fuel injection). Like the 6.0/368" DFI engines before it, the HT4100 used an ECM that incorporated a detailed on-board computer. Every parameter of engine performance could be displayed on the Electronic Climate Control panel while the car was being driven. The HT4100 also adopted other modern design features including replaceable cylinder sleeves, high operating temperature for emission control (210 degrees, compared to 180 in earlier engines), free circulation of coolant between the block and the heads, and bimetal construction that mounted heat-tolerant cast-iron heads onto a weight-saving aluminum block. The engine had a bore of 3.465 in (88.0 mm) and stroke of 3.307 in (84.0 mm), for a total displacement of 4.1 L (250 cu in). It produced 135 hp (101 kW) at 4400 rpm and 190 lbf⋅ft (260 N⋅m) of torque at 2000 rpm.

In 1982 the HT4100 was the standard engine for the longitudinal front-wheel-drive Eldorado and Seville. It was also placed in many rear-wheel-drive DeVilles, and was available for the Fleetwood.

The HT4100 was prone to failure of the intake manifold gasket due to scrubbing of the bi-metal interface, aluminum oil pump failure, cam bearing displacement, weak aluminum block castings and bolts pulling the aluminum threads from the block. It may not have been the most successful engine to sit under the hood of a Cadillac, but potential buyers were no more satisfied with the other two engines available at the time, the V8-6-4 and the Oldsmobile 5.7 L Diesel. Reliability issues soiled the reputation of the HT4100. As a result, the Oldsmobile V8 gas engines were a popular and straightforward conversion. Despite problems with the engines, Cadillac still had annual sales above 300,000 as late as 1986.[2]

For 1987, a more powerful version of the 4.1 L engine was introduced in the Cadillac Allanté, using a different camshaft profile and roller lifters to provide for improved airflow, in addition to multiport fuel injection. This engine was rated at 170 hp (127 kW) at 4300 rpm and 235 lbf⋅ft (319 N⋅m) of torque at 3200 rpm. The 4.1 was superseded by larger-displacement engines such as the 4.5 and 4.9, and the HT4100 ceased production after the 1988 model year.

Vehicles Used In[edit]

  • 1982-1985 Cadillac Fleetwood Brougham
  • 1982-1987 Cadillac DeVille
  • 1982-1987 Cadillac Eldorado
  • 1983-1987 Cadillac Seville
  • 1985-1987 Cadillac Fleetwood

4.5[edit]

Cadillac 4.5 L engine

This was an improved and enlarged version of the HT4100. However, the 4.5 L engine was never classified as HT4500. Engineering advances allowed the company to begin increasing displacement and output again. A bored-out (to 92 mm (3.6 in)) 4.5 L (273 cu in) 4.5 version was introduced in 1988 with 155 hp (116 kW) and throttle body injection. There were various versions of this engine built from its introduction in 1988 to the end of production in 1992 including a high-output LW2 version with multiport fuel injection which produced 200 hp (149 kW) and 270 lbf⋅ft (370 N⋅m) for the Allante. Outside of the Allante, Cadillac introduced a port fuel-injected 4.5 L V8 engine in 1990 with 180 hp (134 kW) and 245 lbf⋅ft (332 N⋅m) across their car line up.

Vehicles Used In[edit]

This engine was used in the following vehicles:

  • 1988-1990 Cadillac DeVille
  • 1988-1990 Cadillac Eldorado
  • 1988-1990 Cadillac Fleetwood
  • 1988-1990 Cadillac Seville
  • 1988-1992 Cadillac Allante

L26 4.9[edit]

Cadillac 4.9 L engine

A larger version of the 4.5, the L26 4.9, debuted in 1991 at 4.9 L with a square 92 mm (3.6 in) bore and stroke. Despite the fact that it had similar output to Allante's 4.5 L port fuel-injected V8, the 4.9 L engine represented a significant upgrade for the remainder of the Cadillac lineup. Horsepower output was up 20 hp (15 kW) from the previous 1990 4.5 L engine and torque was up by 30 lbf⋅ft (41 N⋅m), to 200 hp (149 kW) and 275 lbf⋅ft (373 N⋅m) respectively. Both the 4.9 and 4.5 port fuel-injected engines required premium fuel due to a 9.5:1 compression ratio. The 4.9 produces its maximum horsepower at 4100 rpm. The 4.9 L was used throughout the Cadillac line. It was last used in the 1995 Cadillac DeVille. It was replaced by the newer 4.6 L Cadillac Northstar engine.

Vehicles Used In[edit]

This engine was used in the following vehicles:

  • 1991-1992 Cadillac Fleetwood
  • 1991-1993 Cadillac Eldorado
  • 1991-1993 Cadillac Seville
  • 1991-1995 Cadillac DeVille (base trim only in 1994 and 1995)
  • 1993 Cadillac Sixty Special

References[edit]

  1. ^ Sessler, Peter (2010). Ultimate American V-8 Engine Data Book, 2nd Edition. Minneapolis: Motorbooks. pp. 28, 29. ISBN 978-0760336816. 
  2. ^ "Cadillac wants fewer, stronger dealerships". Automotive News. August 25, 2003.