[ben72227]

Today is Tuesday (December 13, 2005) and we are doing a feature on a group of Cadillac engines today. I know, I know, probably not as interesting as a car model, BUT we have to cover everything in this history class

This weeks topic is none other than....

THE OHV V8s of the 80s! Yay!

HT-4100
Another new V8 appeared in 1982 as the HT-4100 (option code LT8). This engine was originally designed for transverse front wheel drive use in the planned downsized 1983 Cadillac sedans. However, delays in General Motors' BOC (Buick-Oldsmobile-Cadillac) large sedan program and the colossal failure of the L62 V8-6-4 caused the HT-4100 to be rushed into production for the 1982 model year.
The 4.1 L HT-4100 featured an unusual aluminum block with iron head construction. Bore was 88 mm and stroke was 84 mm; in most applications, it was equipped with throttle-body "digital" fuel injection. Initial output was a paltry 125 hp (93 kW), not nearly enough to provide Cadillac-level acceleration in the heavy Cadillacs of the early 80s (which were designed for a much bigger V8); early models were plagued with reliability problems. Later versions of the HT-4100 were used in the originally-planned front wheel drive configuration throughout the Cadillac line (with the exception of the limousines and the Cimarron).
The version found in the 1987 Cadillac Allante featured port fuel injection, with output of 170 hp (126.8 kW) and 235 ft.lbf (319 Nm) of torque. The 4.1 was superseded by larger models and ceased production in 1988.

HT-4500
Engineering allowed the company to begin to raise displacement and output again. A bored-out (to 92 mm) 4.5 L HT-4500 version was introduced in 1988 with 155 hp (116 kW). Various versions were built between this introduction and the end of production for this engine in 1992, including a high-output LW2 with multiport fuel injection version for the Allante which produced 200 hp (149 kW) and 270 ft.lbf (366 Nm).

HT-4900
An even larger version, the L26 HT-4900, debuted in 1991 at 4.9 L with a square 92 mm bore and stroke. Power was the same as the 4500 at 200 hp (149 kW) but torque was up slightly to 275 ft.lbf (373 Nm). The engine was produced until 1996.
This Cadillac V8 series was used in the following models:

• Cadillac Allante
• Cadillac Deville
• Cadillac Eldorado
• Cadillac Fleetwood
• Cadillac Seville

This engine was phased out in favor of the newer Cadillac Northstar engine in the mid-1990s.

Rear-wheel-drive Cadillacs
From 1982 to 1985, all RWD Cadillacs (except for the limousines) featured the HT-4100 V8, though this could be replaced with a 4.1 L Buick LD5 V6 or a 5.7 L Oldsmobile LF9 Diesel V8. From 1986 to 1989, the rear wheel drive Cadillacs - the Fleetwood Brougham and Brougham - used a 5.0 L (307 in³) Oldsmobile 307 carbureted V8 (replacing the HT4100). In 1990, a 175 horsepower, fuel-injected 5.7 L (350 in³) Chevrolet Small-Block V8 became available to coachbuilders. In 1991, the Oldsmobile 307 was replaced with a 5.0 L (305 in³) fuel-injected Small-Block V8; the 350 in³ Small-BlockLT1 V8 with 260 hp (194 kW), which the Fleetwood would use until it was discontinued in 1996. became available in non-coachbuilder vehicles as well. In 1993, the 180 hp (134 kW) 350 in³ V8 became standard in the newly-renamed Cadillac Fleetwood; in 1994, this was upgraded to a detuned Corvette.


HT 4100: