Model A & B

Ford Garage

AER Insert Main Bearing Data & Instructions

This page details the installation instructions of the main bearing inserts produced specifically for Model A & B Ford engines by Rich Fallucca at Antique Engine Rebuilding (AER).

These modern insert bearing shells are specifically engineered for the Model A and B engine, and are not an adaptation of an existing bearing from another application. The bearing shells are steel backed, and have modern aluminum (not babbitt) bearing surfaces.

The insert bearings are manufactured for AER to precise dimensions by an OEM engine bearing company, and require the block, caps, and crankshaft to be prepared and sized to precise dimensions to receive them. See the table and information below for details.

Model A:
Crankshaft
Finished Journal
Diameter
Max / Min
inches
Recommended
AER Bearing
Set Number
Block & Cap Bore
Diameter & Finish
60-90 µin Ra
Max / Min
inches
Description
1.6259 / 1.6254 A Standard 1.7710 / 1.7705
1.6239 / 1.6234 A 002 Under 1.7710 / 1.7705 For new Burlington, and NOS Ford A crankshafts
1.6159 / 1.6154 A 010 Under 1.7710 / 1.7705
1.6059 / 1.6054 A 020 Under 1.7710 / 1.7705
1.5959 / 1.5954 A 030 Under 1.7710 / 1.7705
1.5859 / 1.5854 A 040 Under 1.7710 / 1.7705
1.5659 / 1.5654 A 060 Under 1.7710 / 1.7705
Model B:
Crankshaft
Finished Journal
Diameter
Max / Min
inches
Recommended
AER Bearing
Set Number
Block & Cap Bore
Diameter & Finish
60-90 µin Ra
Max / Min
inches
Description
1.9990 / 1.9985 B Standard 2.1350 / 2.1345 For NOS Ford B crankshafts
1.9890 / 1.9885 B 010 Under 2.1350 / 2.1345
1.9790 / 1.9785 B 020 Under 2.1350 / 2.1345
1.9690 / 1.9685 B 030 Under 2.1350 / 2.1345
1.9590 / 1.9585 B 040 Under 2.1350 / 2.1345
1.9390 / 1.9385 B 060 Under 2.1350 / 2.1345

Additionally, Rich Fallucca supplies machined bronze thrust washers for the rear main journal which are designed to work with his bearing inserts, or in place of the original cast and machined babbitt thrusts when using babbitt bearings.

These bronze thrust washer sets can be fitted to engines having original babbitt bearings, as well as being recommended for use with modern insert bearing shells. The same block and cap preparation for bronze thrust washers is required in either application.

Cost
Model A Insert Main Bearings (6 piece set) $85.00
Model A Bronze Thrust Washers (3 piece set) $27.00
Model B Insert Main Bearings (6 piece set) $90.00
Model B Bronze Thrust Washers (3 piece set) $30.00

To purchase insert bearing sets, bronze thrust washer sets, or complete engine rebuilding services, contact:
Rich Fallucca
4835 Louise
Skokie, Illinois 60077
(847) 674-6716
www.antiqueenginerebuilding.com


Model A Block and Bearing Cap Preparation Instructions

The block and caps are to be installed with no shims, and align bored, finished, and prepared to receive the main bearing inserts and bronze thrust washers.

Some blocks, mainly early 1928, may require elongating the oil feed holes in the block to align with the oil holes in the insert bearing shell.

Model A Block and Cap Preparation:
  1. Carefully inspect the main bearing caps and the block mating surfaces for damage or disruption. Ensure the caps fit precisely to the block surface without wobble, gap, or variation.
  2. Mark and identify the front and center main bearing caps for repeatable location and orientation on the block. The chosen cap, position, and orientation should be maintained throughout all machining and subsequent assembly and future service procedures.
  3. Assemble the main bearing caps to the block with no shims.
  4. Align bore and hone the block and bearing caps to the size and finish indicated in the table above.
  5. Remove all caps and cut slots in the block bearing saddles and bearing caps for the aligning lugs on the insert bearing shells. Confirm the alignment of the oil feed in the block with the hole in the insert bearing shell before cutting the block relief for the aligning lugs.
  6. Place bearing inserts in the block saddles and caps, and check that the aligning lugs and oil holes fit and align correctly.
  7. Using Prussian Blue, there should be at least 80% contact of the bluing on all bearing inserts to the block and caps.
  8. Counter bore the rear of the block rear main bearing saddle and bearing cap 2.250 inch OD (2.875 inch OD for Model B) and 0.125 inch deep to receive two semi-circular bronze thrust washers.
  9. Remove the rear main cap and counter bore the front of the rear main saddle (only) in the block for a single thrust washer at the front.
  10. It is recommended to use two thrust washers on the back of the rear main, and one of the washers should be doweled to the block or cap to prevent rotation.
  11. The counter bore holds the two rear thrust washers in place, and the crankshaft keeps them in position.
  12. The dowel keeps the rear thrust washers from rotating, and the cap keeps the single front thrust washer from rotating.
  13. Thrust washers are not to be rigidly secured or attached to the block or cap as this can cause end loading and premature wear.
  14. Fit the thrust washers in the block and rear bearing cap.
  15. File any portion of the thrust washer that extends beyond the block-to-cap parting line.
  16. File a large bevel on both edges of the front thrust washer only (the contact face of crankshaft thrust). Leaving a square edge on the thrust would cause oil to be wiped from the crankshaft.
  17. A small amount of RTV sealer is recommended to be used on the outside edges of the rear main cap to prevent oil leaks at the rear.

Model B Block and Bearing Cap Preparation Instructions

The Model B instructions are the same as for the Model A, except for the larger diameters of the bronze thrust washers and the bearing inserts. Refer to the Model B table above for block and cap bore sizes.

The rear of the Model B block rear main bearing saddle and cap are both to be counter bored 2.8750 inch OD and 0.125 inch deep for two bronze thrust washers.

Remove the rear main cap and counter bore the front of the Model B rear main saddle (only) in the block 2.8750 inch OD and 0.125 inch deep for a single bronze thrust washer.


Shown above is a Starrett V-Anvil micrometer. This type of three-point micrometer is designed to measure shaft diameters very accurately and repeatably, compared to other tools such as conventional micrometers or vernier/digital calipers.


More related information on Ford Garage:

  1. Model A Burlington Forged Counterweighted Crankshaft
  2. Model B Ford-Köln G28T-6303-B2 Counterweighted Crankshaft  

April 2017