EVOLUTION OF THE MODEL A FORD ENGINE

The Model A engine and its derivatives were manufactured beginning in the fall of 1927 and continued until 1958. During this manufacturing span, several improvements were made to the basic design, however all of these improvements still fall short of modern engine design practices. The following chart illustrates the evolution of the Model A engine family and shows many of the changes that were made throughout its evolution.

 

YEARS	SERIES	HP@ RPM	BEARING SIZE (in)	BEARING TYPE	OIL SYSTEM	REAR MAIN SEAL	CRANK CWT’S	EXH VALVE SEAT
’27-‘31	Model A	40@ 2200	R 1.500 M 1.625	Poured Babbitt	Gravity and Dip	Slinger	None	None
‘32	Model B 1st Design	50 @ 2800	R 1.875 M 2.000	Poured Babbitt	Low Press And Dip	Slinger	None	None
’32-‘50	GAZ A USSR	40@ 2200	R 1.500 M 1.625	Poured Babbitt	Gravity and Dip	Slinger	None	None
’33-‘34	40, 46, (Model B) 2nd Design	50 @ 2800	R 1.875 M 2.000	Poured Babbitt	Low Press And Dip	Slinger	Partial ~ 40% Integral	None
’35-50	GAZ M USSR	50 @ 2800	R 1.875 M 2.000	Poured Babbitt	Low Press And Dip	Slinger	Partial ~ 40% Integral	None
Late 30’s	<> A	40@ 2200	R 1.500 M 1.625	Poured Babbitt	Gravity and Dip	Slinger	None	Yes
Late 30’s	<> B	50 @ 2800	R 1.875 M 2.000	Poured Babbitt	Low Press And Dip	Slinger	Partial ~ 40% Integral	Yes
Late 30’s	Factory Rebuilt B	50 @ 2800	R 1.875 M 2.000	Poured Babbitt	Low Press And Dip	Slinger	Partial ~ 60% Pressed	None
’42-‘58	G28T German	57 @ 2875	R 1.875 M 2.000	Replaceable Insert	Full Pressure	Packing	Partial Integral	Yes

 
Comparing the evolutionary chart above to the design differences noted earlier, it can be seen that most of the design deficiencies between the Model A engine and a modern engine were narrowed throughout the evolution. 

Also, as can be seen from the evolutionary chart, the latest engine, the G28T engine was a vast improvement over the Model A engine; however it is still not up to modern engineering standards since it only had three main bearings and a partially counterweighted crankshaft. It should also be noted that the exterior appearance of the G28T engine looked like a modified Model B engine, which is somewhat different than a Model A engine.

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