Model A & B

Ford Garage

LEMPCO Align Boring Machine

Model FSU (Fast Set Up)

For Babbitt Main Bearings

LEMPCO Align Boring Frame

Shown above is LEMPCO main bearing boring bar frame and fixtures for machining the poured babbitt bearings on the Model A and B Ford engine block.

When used on vintage Fords, the LEMPCO line boring bar locating system relies on the location of the camshaft bores directly to space the boring bar centerline to the theoretical camshaft centerline.

Alternatively, Kwik-Way boring bar locating fixtures can be used with the LEMPCO boring frame to position the bar and frame according to the main bearing datum holes, instead of to the camshaft bores in the block.


Tobin-Arp

Shown above is a pair of Tobin-Arp B-138 main bearing boring bar locating fixtures used with both the TA-14 and TA-15 machines. They are similar to those of the LEMPCO boring frame for the Model A and B Ford engine block. The Tobin-Arp uses a 1-1/8" diameter boring bar, whereas the Kwik-Way and the LEMPCO use a 1-1/4" bar.

These fixtures insert into the cam bearing bores in the block to locate and support the boring bar centerline, according to the camshaft bore centerline location, and the pan rail datum surface.

In this way, the Tobin-Arp fixtures directly locate and control the centerline dimension between the engine camshaft and crankshaft, which is important to maintain proper timing gear engagement and clearances.

They also do not interfere or obstruct the main bearing caps and bolts.

In theory, this is a robust strategy for locating the main bearing boring bar (to the camshaft) in an engine design having a direct camshaft and crankshaft gear engagement, like a Model A Ford.

However, the cam and crank alignment and engagement could be compromised when using this strategy to set up on a worn block. If the block has excessive wear in either the front or rear camshaft bores, this method of locating off of the camshaft bores can introduce error in the proper placement of the boring bar in the block. This condition is often found on the front bore on Model A's and B's. Measure cam bores for egg shape. Check your work carefully and confirm position before cutting.


More related web pages on Ford Garage:

  1. Model A & B Camshaft to Crankshaft Gear Alignment
  2. Model A & B Proper Crankshaft and Camshaft Positioning
  3. Model A & B Boring Bar Fixtures
  4. Kwik-Way Line Boring Machine Operating Instructions
  5. Kwik-Way Line Boring Machine Parts List

August 2010