The Ford Model AA came with the A chassis engine, A chassis 3-speed or AA 4-speed transmission. The Dual High was an underdrive factory option for AA’s with the 3-speed transmission. The Warford 3-speed transmission was available as aftermarket equipment (among other suppliers). The AA rear axles came with two gear ratios for all years. Combinations of this equipment effected the top MPH which an AA could obtain (i.e. the MPH on a flat surface, no load, no wind resistance, etc.)
The chart at the right (click to enlarge) provides four sections of information regarding AA truck MPH. Each section is for a given engine RPM and provides MPH for various equipment combinations.
The Microsoft Excel work book from which the above chart was produced can be downloaded using this link >>> AA-MPH. The work sheet contains the formulas used. So, one can change values to show different results as desired.
An original engine id was made up of a prefix and a number. The id had a ☆ on each end. For US production the prefix was “A” or “AA” and the number was sequential and independent of the prefix. An example engine id would be ☆AA1356549☆ as shown on the left. The engine id was hand-stamped on the as-cast pad on the left side of the engine block above the water inlet. Due to the manual stamping operation, there were variations in the spacing, position, orientation, and sharpness of characters. The engine id usually became the vin# on the title.
The number allows for the identification of the month when a given engine passed an engine run-in test. After stamping, the engine was released for vehicle final assembly.
Note that the engine number only dates the final approval of the assembled run-in engine, not the casting dates of the engine components, not the actual assembly date of the engine components, and not the assembly date of the vehicle.
Due to the excess engine production and the large number of engines “in float” between the Rouge plant and the 45 assembly plants in the United States and Europe, the numbers can only be used to establish the approximate production date of a Model A or AA. By the end of 1930, for example, there were 215,556 excess engines. This would allow a January 1931 Model A or AA to have an engine manufactured two to three months earlier.
|A/AA Vehicle to Engine Production Comparison|
|Year End||Vehicles||Engines||Excess Engines|
|Neil Wilson 2014|
At the individual assembly plants where each engine was installed, the id was also stamped on top of the frame’s left hand side member near the clutch petal as shown to the right. With the body or cab mounted, the id on the frame could not be seen.
The “AA” prefix identified engines with a stronger clutch spring allowing the engine to be identified on the assembly line for installation into an AA chassis.
Note: for about 2-1/2 month, starting mid February 1928 (with engine ID A-26268) through most of April, the AA truck clutch spring was the same as the Model A. During this period the engine ID only had the “A” prefix. Refer to the “Service Letters” dated February 23rd and May 15th 1928. Note that an AA with engine and frame ID of AA-98977 has been found. This is a late April 1928 number and helps define the end of the “A” prefixed ID’s for the AA’s.
|Month||First #||Last #||Total #|
|Neil Wilson 2014|
|1927 Year End Total ————————–||5,275|
|1928 Year End Total ————————–||804,847|
|1929 Year End Total ————————–||1,932,573|
|1930 Year End Total ————————–||1,494,805|
|1931 Year End Total ————————–||593,306|
|1932 Year End Total ————————–||18,534|
Check out the Links page for other sites with expanded details regarding the engine id.
Ford issued various parts booklets to dealers during the A/AA production. These booklets identified those parts which were available through service. Many of the parts listed were also the parts being used at the Ford assembly plants at the time of the booklet’s release. Some of the parts listed were not current production parts but were available as service replacement parts. These replacement parts may or may not have been exactly the same design as the original production part.
Parts were assigned an id consisting of three items – prefix, number, suffix (like AA-1015-B). These three id-items are described below:
Part prefix – “A” or “AA” – AA was used for those parts which were only used on the AA vehicles. Parts used on both the A and AA were assigned an “A” prefix. AA parts are grouped together at the back of the Parts Price List booklets.
Part number – a number which allowed parts to be grouped. Example – the transmission and clutch parts group was 7000-7999.
Part suffix – none or letter (exception – “R” was reserved to identify a part no longer in production but available through service):
R-suffix – any part id with an “R” in the suffix indicates that the part was only available through service (i.e. it was not a current production part). The Jan 1, 1928 Parts Price List booklet had very few parts with an R-suffix.
One example of an exception to this rule was the worm drive rear axle. Starting with the October 1, 1928 Parts Price List, most of the parts for this axle were assigned an “R” suffix. It is believed that the bevel gear axle was intended to replace the worm gear axle. However, this didn’t happen but the “R” was never removed from the worm gear axle part id’s.
no-suffix (i.e. blank) – an initial unique production design part. Example – part “AA-1015 – wheel” was the first production wheel used for the AA and carried no-suffix (no other AA wheel existed at the time this steel spoke wheel was used in production). Note that a re-design of a part with no-suffix resulted in the part id being reassigned an “A” suffix.
letter-suffix (such as A, B, C, D, etc.) – a non-unique part:
Example 1 – part “A-13010-A – head lamp case and support assembly (nickel)” and “A-13010-B – head lamp case and support assembly (black)”. Both of these acorn shaped headlamp cases were used in production at the same time and therefore each was assigned suffix for identification.
Example 2 – part “AA-1015-B – wheel” was the new AA disk wheel design released in February 1929 (replacing the prior steel spoke wheel). The prior steel spoke wheel part id had no suffix and was assigned a suffix of “A” for identification. The id was also assigned an ending “R” indicating it was only available through service (i.e. not a production wheel). So, the steel spoke wheel part id became AA-1015-AR in the first 1929 Parts Price List booklet.
suffix note 1 – new suffix letters (such as A, B, C, D) were not assigned to redesigned parts which were backward compatible with the prior part. The new part was simply placed into production using the prior part id. Example – the 1930/1931 AA wheels had four designs but the wheel id remained AA-1015-C for all four designs. Each of these designs can only be dated through the use of Ford records, engineering drawings, Service Bulletins, Branch letters and observations of original AA’s.
suffix note 2 – Some no-suffix parts were obsoleted without having a similar replacement and therefore only had an “R” suffix. Example – part “A-2473 Brake equalizer operating shaft pin” was eliminated as a result of a new brake system design. The obsoleted part became “A-2473-R Brake equalizer operating shaft pin”. The “R” suffix showing that the part was no longer used in production, but available through service.
Ford issued a number of releases of a “Body Parts List” booklet (5.5″ x 8.5″) covering the A and AA bodies. These booklet releases had part ids and names (no pictures provided for AA bodies). These booklet releases are not easy to use but offer lots of good information for research and for determining the original Ford name for parts.
The first two booklet releases were titled “Price List of Body Parts”. These releases included both a body parts and a price list section. Subsequent releases were titled “Body Parts List”. A separate booklet provided the price list by part.
Ford issued a number of releases of a “Parts Price List” booklet (5.5″ x 8.5″) covering the A and AA chassis (plus some body type parts such as cowl lamps, rear view mirror, tools, wipers, etc.). Booklets had three sections (Model A, Standard Parts, and Model AA). Each booklet release contained a list of those parts available through service as of the cover date. Included were both current production parts and service only parts (i.e. parts not currently in production). Many parts were assemblies. Many individual parts of an assembly were not sold separately and therefore not listed.
Note that the first release of this booklet (January 1, 1928) did not include any AA parts. An April 15, 1928 release covered the AA only. Thereafter, each release had both the A and AA. Pictures of many of the parts are also shown in these booklet releases.
Each booklet section is subdivided into part groupings (such an Wheels, Service Brakes, etc.). The part listing within the A and AA sections shows the part id, part name/description, price, and number per car (i.e. vehicle). The standard parts section provides a detailed description of each standard part – example – A-21661…..1/4-20 U.S.S. (9/16 x 1/2) sq. nut.