Model A & B & Model 46

Ford Garage

Camshaft Gear Front Timing Cover Differences

The following pics show each of the major styles of camshaft gear front timing covers used from 1928 to 1934 (and beyond), and a comparison pic of all of them in order to the show variation in generator position.

Shown directly below is a rare timing cover without the timing pin hole. This cover was used on some very early Canadian built export models. The engine was timed through a hole in the flywheel housing. Also note the unusual rear motor mount. The pics below were provided by Justin Bicknell of New Zealand, and are from his early Canadian engine number ☆CA 67☆.

Pictured above is the A-6019-A cover which was used in 1928, and later on 157" inch wheelbase Model AA trucks where the engine was mounted directly to the rear flange of the frame front cross-member. Some of the very earliest of these covers used a 7/16 inch generator mounting bolt. Subsequent ones used a 1/2 inch bolt.

Also note the machined surface and lip for supporting the casting on the frame flange. This is also the only cover which was spot face machined at the block attaching bolt holes. Subsequent covers were just a 'close enough' as-cast surface under the bolt and washer.

The timing pin hole in the Model A covers correspond to TDC (zero crankshaft degrees) on the number one piston.

Pictured above is the typical A-6019-B cover which was used through out Model A production with the front flexible motor mount. Note the revised casting ears which only bear on the tops of the motor mount. The mounting holes are on 9 inch centers.

Model A Service - Post-Production

Pictured above is the somewhat unusual A-6019-BR cover which was supplied to service for Model A's after 1932 Model B production began. Ford created a new casting with a revised generator mounting location and an elongated boss for the timing pin hole.

This casting was used to make both Model A and Model B part number covers (having timing pin holes in different locations on the boss). This cover pictured above was for post-1931 service use, and was not used on original production Model A's.

In this design, the generator was moved upward and slightly farther from crankshaft centerline to accommodate the Model B front lower water hose.

The timing pin hole could be drilled in the standard Model A position (low) on the boss as this one is, or in the advanced position (high) on the boss to accommodate the Model B distributor.

Model B

Pictured above is the 1932 Model B cover B-6019. It is identical to the Model A (service) cover, except the B-6019 cover has the timing pin hole in the advanced position on the boss. The timing pin hole in the Model B cover corresponds to 19 crankshaft degrees (9-1/2 camshaft degrees) BTDC on the number one piston.

German Ford Köln G28T

The cover used on the German Ford-Köln 1942-54 vintage G28T engine was also similar to the Model B cover shown above. One thing that made the G28T front timing cover unique compared to other Model B covers was that the timing pin hole was not on an oval boss like a Model B, it was just a hole on a simple round boss resembling that of a production Model A cover, but having both the boss and hole located in the advanced Model B position.

The G28T cover also had the Model B style generator mounting position and casting design, not the Model A style.

The G28T cover is also identified by the cast-in Ford Köln logo, pictured above, which is visible on the outside of the cover above the crankshaft nose. Ford Köln was the plant in Germany (Köln) where the G28T improved B engine was produced in the 1940s and 1950s. The regular European Ford Model B engine was produced at both Dagenham, England and Köln, Germany in the 1930s.

1933-34 Model 40/46

Pictured above is the 1933-34 timing cover 46-6019 as used on 4 cylinder Model 40 and 46 passenger and commercial. This cover has the timing pin hole in the same 19 crankshaft degrees BTDC advanced position as a Model B, but the hole is not on an elongated boss. This cover also has the front motor mount bolt holes moved closer in towards center, on 6-3/8 inch hole spacing.

Most notably, the generator mounting boss is moved considerably upward and rearward. This was done to offset the generator rearward in conjunction with the short Model 46 (Model B style) water pump, and the short flat crankshaft pulley.

The purpose of the short water pump was to shorten the overall engine length to provide enough fan clearance to the Model 40/46 radiator, which was laid back at an angle on the 1933-34 Model 40/46 Fords.

Final Considerations:

This last pic (above) is a front view of the earliest through newest covers to illustrate the relative differences in the generator mounting positions.

In some respects, the A-6019-BR service cover (middle one above) might be the most convenient to have on a Model A since it puts the generator up higher away from the lower water hose. I have seen a number of generator brackets cutting into the lower hose on Model A's, and it is also difficult to reach the generator mounting bolt for service with the original covers.

Model B Distributor Timing:

The Model A service cover A-6019-BR (with the timing pin hole at the bottom of the elongated boss) is not really compatible for use with the Model B distributor even though it resembles a Model B timing cover.

Proper initial timing of a Model B distributor will not being achieved when timing "by the book" and if using a Model A timing cover.

The Model B distributor is intended to be timed using the Model B cover (which has the 9-1/2 camshaft degree advanced location of the timing pin).

Improper timing cover usage with a Model B distributor results in retarded spark timing and loss of power and top speed.

It might be a good idea to double check your cover if you are running a Model B distributor and think you have a Model B cover. It is possible you might have the Model A service cover with the timing pin hole at the bottom of the elongated boss, rather than at the top (Model B).


More Distributor and Timing web pages on Ford Garage:

  1. Model B & Model 46 Distributor Design Details
  2. Model B & Model 46 Distributor Advance Operation
  3. Model B & Model 46 Pertronix Ignitor Ignition Installation and Timing
  4. Model A & B Camshaft Thrust Plunger
  5. Model A & B Engine Cam/Valve and Ignition/Spark Timing Discussion

January 2002