Work, development and fine-tuning continued on the M1A, resulting in the M1B of 1965 and 1966. Michael Turner, Tyler Alexander, and Robin Herd were among the individuals responsible for many of the new changes. Improvements and changes included changes to the tail and to the nose section. Robin Herd worked on stiffening the chassis, resulting in a chassis that was more rigid yet still the same weight.
The inaugural Group 7 racing debut for the M1B was at the St. Jovite race. Sadly, the car retired prematurely due to problems with the Oldsmobile engine. When the car began competing in CanAm competition, it soon became apparent that the 5-liter Traco-Oldsmobile engine was unable to compete with the 6-liter Chevrolet powerplants. After a few races, Bruce McLaren switched the lightweight aluminum engine for the heavier, yet more powerful, 5.4-liter Chevrolet units. The result was an increase in weight by about 200 lbs but an increase in horsepower by 100.
Bruce would finish the season in second place behind Jim Surtees. By Daniel Vaughan | Jul 2009McLaren produced the M1B, a Group 7 racing car that became a successful competitor in the nascent Can-Am series, for 1965 and 1966. The car was a development of McLaren's first Group 7 racer, the M1A.
Like its predecessor, the M1B initially used a 4.5-liter Traco-Oldsmobile V8 as its source of propulsion. Despite the aluminum Oldsmobile V8's light weight, though, its small displacement made it a particularly uncompetitive unit in the M1B. Bruce McLaren decided to switch over to a more powerful cast-iron V8 to create a more competitive vehicle. A 5.4-liter Chevrolet motor replaced the Oldsmobile power plant, with the Chevy engine weighing an additional 200 pounds but providing an extra 100 horsepower. The Chevrolet mill's displacement eventually rose to 6.2-liters, with power output of 550 horsepower.
McLaren engineer Robin Herd endowed the M1B with a frame that, despite weighing about the same as the M1A's, proved 20% stronger than its predecessor's chassis. The extra strength came from the use of larger diameter round and square tubing, with alloy sheet metal bonded and riveted to the tubular frame.
Under a partnership with Elva, 28 examples of the M1B were produced. These cars were marketed as McLaren-Elva Mark 2s.
Stronger and more powerful than the M1A, the McLaren M1B was a capable performer. The M1B represented the phenomenal success of Bruce McLaren, who not only built exceptional racing cars but also raced them with brilliance. Just a few years before his early death, Bruce McLaren drove the M1B to second place (behind only John Surtees) in the 1966 Can-Am season.
'McLaren Elva M1B.' Mathews Collection n. pag. Web. 11 Jun 2011. http://www.mathewscollection.com/former/Former_McLaren_M1B.htm.
'McLaren M1A' & 'McLaren M1B.' Bruce McLaren Trust n. pag. Web. 11 Jun 2011. http://www.bruce-mclaren.com/the-cars/sports-cars/m1b.html. By Evan Acuña