AMERICA'S FIRST DIE-CAST ALUMINIUM ENGINE

AMERICA'S FIRST DIE-CAST ALUMINIUM ENGINE 1961-1964

(1993 Rambler Reader, Vol. 14 No. 2)

It was a fad of the times. All the major automobile manufacturers were getting on the bandwagon, and AMC was right there with them. Auto makers were crazy about aluminium engines. And AMC was the leader in presenting a die-cast aluminium engine to the public. Yes, AMC again scooped the field with the introduction of its aluminium 196 six cylinder engine in 1961. America's first die-cast aluminium block six. The new engine was backed by six years' of design experience with die-cast aluminium engines and 2 million test miles on proving grounds, highways and the track.
The die-cast aluminium alloy cylinder block weighed only 60 pounds and reduced overall front end load by 80 pounds due to lighter component and suspension requirements. Precision, high-pressure die-casting processes assured absolute uniformity and high quality.

Centrifugally cast iron cylinder liners with a wall thickness of .093 inches were mechanically and chemically permanently bonded to the aluminium block. Hydraulic valve tappets and full flow oil filter were added to assure quiet operation and a long life. Topping off the aluminium engine block was a cast iron head featuring integral valve guides and new exhaust valves. The main and connecting rod bearings were steel-backed copper-lead alloy for longer service life.

In addition to the 2 million miles of testing AMC subjected the aluminium engine to on proving grounds, AMC put the new engine through a million mile test at Daytona International Speedway under official NASCAR supervision. Running night and day, week after week, ten Ramblers powered by the new aluminium block engine piled up a total of 1,000,000 miles of gruelling, high speed driving to prove beyond any question the superb durability, economy and performance of the most advanced engine on the American road. Although the specifications of the aluminium engine and the tried and true iron block six cylinder engine were identical in all respects, there was no similarity in outward appearances. For one thing the aluminium engine was unpainted.

For the first year of its introduction, 1961, the aluminium engine was offered as an option on Deluxe and Super models of the full sized Rambler Classics. AMC wanted to test the water before leaping in. Nevertheless, the aluminium engine was made available for fleet applications in the Rambulance and in taxicabs, which demonstrates a high degree of confidence in the new design.

Through its press releases, AMC disclosed more about the aluminium engine than is to be found in its sales literature and dealer specifications books. The press releases disclosed that the lighter engine permitted better balance and weight distribution which promoted greater stability and easier handling. The new engine was the result of a co-operative research and development program between American Motors and the Doehler-Jarvis Division of National Lead Company. Doehler-Jarvis was responsible for the production of the aluminium blocks in its Toledo, Ohio plant. The block was made of a special aluminium-silicon alloy for hardness and controlled temperature expansion. Hydraulic valve lifters were used exclusively for quiet operation and a newly designed oil pump eliminated the possibility of hydraulic lock and assured proper pressure calibration. A full-flow oil filter was standard equipment. The new engine demonstrated improved performance which was attributed to a redesigned intake manifold which provided increased fuel-air velocity. The crankshaft was completely balanced for smooth vibrationless performance. During the developmental stage of the aluminium engine, it was tested by the use of the latest aircraft industry method of applying cemented plastic with polarised light to establish static and dynamic stress points. Unfortunately, available production information does not disclose how many aluminium engines were installed in Deluxe and Super Classics in 1961.

By the time the 1962 Rambler Classics were introduced AMC was able to say that the aluminium engine had been subjected to over 3 million miles of owner use. From this figure it is possible to make a rough guess as to the number of these engines installed as optional equipment on the Classic Deluxe and Super models. Assuming that the average driver in 1961 drove approximately 12,000 miles a year and adjusting this figure to compensate for the fact that some cars were bought when first introduced and others toward the end of the 1961 sales year, we could say that about 500 engines found buyers. However, of this 3 million miles, 1 million had already been driven by AMC on the test track. We are now down to around 300 engines sold. For all the effort that went into the development of this engine, those sales figures are very disappointing, to say the least. To help boost sales, AMC now made the aluminium engine standard equipment on the 400 series of the Classic, while it remained an option on the Deluxe and Custom lines. For those customers who really did not want the aluminium engine,, the old reliable cast iron six was available on the 400 line as an option, presumably at no cost. Other than this change, everything remained the same. If all Classic 400 models sold in 1962 were equipped with the standard aluminium engine,, there would have been 58,057 aluminium engines sold in 1962. Even if a fraction of the cars in 1962 actually were equipped with the aluminium engine, the total installed would have been significantly greater than the 300 plus we have estimated for 1961. Though the press releases in 1961 stated that full-flow oil filters and hydraulic valve lifters were used, the data books tell us another story - solid lifters and partial-flow filters were standard.

For 1963 the aluminium engine was standard on the Classic 770 and optional on the 550 and 660. The cast iron six could be had at no extra charge in place of the aluminium engine on the Classic 770. With the introduction of AMC's new Tri-Poised Power for 1963, the engine mounts on the aluminium engine were changed to accommodate the new method of suspending the engine on the chassis. Just over 60,000 Classic 770 models were sold in 1963. As with the 1962 sales on the 400 line, it is doubtful that they were all equipped with the aluminium engine. And, available production figures support this fact. There were 45,998 1963 Classic 770s equipped with the aluminium engine, which accounted for just over 76% of those sold. When we look at the number of those cars that have survives today, it is immediately apparent that the engine must have been quite troublesome. The Classic 770 with aluminium engine today is a very rare automobile indeed. If we assume the same percentage of aluminium engines were installed in 1962 as in 1963, we can arrive at a figure of 43,000 for 1962. Again, the survival rate is very low.

The last year for the aluminium engine was 1964. AMC introduced the new cast iron 232 cid six cylinder engine in 1964 and it replaced both the aluminium and cast iron 196 cid engines in 1965. For 1964 the aluminium engine was optional on all Classics and no longer a standard engine in any AMC. Exactly 4,939 aluminium engines were installed in 1964 Classics. Apparently the durability of the engine had not proven to be what AMC had hoped. From the comments of owners within AMCRC it seems that the engine was technically a good design and that quality of construction was satisfactory. The problem was the combination of cast iron head and aluminium block which caused problems due to electrolysis and differing rates of expansion and contraction. Also, owner maintenance of the aluminium engine was a cause of failure. The aluminium engine required more stringent compliance with the maintenance schedule than the cast iron engine, and owners either were not clearly advised about this special requirement, or they just treated the engine as they would have treated a standard cast iron engine. Unfortunately, if the engine coolant got low or the car over heated, damage to the aluminium block was almost a certainty. A cast iron block was much more forgiving and that is the way most people probably got into trouble with their aluminium engines. When an owner did experience difficulties with the aluminium engine, dealerships would usually replace the engine with a cast iron substitute rather than attempt repairs. All in all, it was a noble experiment but a big disappointment for AMC. A bitter pill swallowed quietly. There is nothing we have available from AMC that discusses the demise of America's First Aluminium Block Engine.