INSERT MAIN BEARINGS

DESIGNED FOR THE MODEL "A"

Inset bearings provide durable and stronger bearings for the engine.  As we drive longer times at

higher speed the demand for updating the Model A engine is essential part of rebuilding.

Tri metal lined bearings designed for the Model A block have holes drilled with integral

oil groves to give more bearing surface with proper lubrication.

NOTES

Inset main and rods work fine with out any changes to oil system. Bearings work with or without pressure oil system.

Oil filter gives longer life but not required. Change oil regularly with modern motor oil.   

Contact rear main oil seals are not necessary.  

The block does require machining to install inserts the first time. 

Main bearings are same OD. and ID. as MG bearings. Only 2 shells per journal instead of 4 or 6. 

Available in STD. as well as 010, 020, 030, 040.

 MAIN BEARING INSTRUCTIONS

                       Crankshaft size

Standard                                1.6254/1.6259

010 Undersize                        1.6154/1.6159

020 Undersize                        1.6054/1.6059

030 Undersize                        1.5954/1.5959

040 Undersize                        1.5854/1.5859 

The block and caps installed with no shims will require align boring.  The housing bore in block is to be1.7705/1.7710.  the finish  60-90 mico inches ra.  The back of the rear main bearing block and cap portions are to be counter bored 2.250 OD and .125 deep.  Now remove cap and counter bore block only on front of rear main 2.250 OD and 125 deep.Remove all caps and cut slots in block and caps for aligning lugs.  Place bearings in block and caps check that aligning lugs and oil holes fit correctly some blocks mainly early 28 may require elongating oil holes in bearings.  80 percent alignment is good. Fit thrust washers in block and cap.  Now file any portion that extends higher then parting line. File large bevel on both edges of front thrust washer 1 only (the contact face of crankshaft thrust)   A square edge will cause oil to be wiped from crankshaft.  On the back of the rear main  it recommended to use 2  thrust washers and 1 of the washers should be doweled to block or cap to prevent rotating.  The counter bore holds washers in place, crankshaft keeps them in position.  The dowel keeps the rear from rotating and the cap keeps front from rotating.  Thrust washers are not to be secured to block or cap as this can cause end loading and premature wear. I recommend a small amount of RTV sealer be used on out side edges of rear main cap to prevent leaks.   

 Main bearing set           $85.00

Thrust washer set          $27.00