Straight Side Bolt Main Caps

1. Clean all main bolt holes on block with a tap. A bottoming tap is recommended. Each hole should be checked to ensure bolts do not bottom out, if bolts bottom out an incorrect torque reading will result. For maximum strength main studs should be used.

2. Clean block and caps, removing all burrs and imperfections. Install the caps on the block.

3. Torque all bolts in an inside to outside pattern, using oil.

7/16” bolts torque to 65 ft. pounds

½” bolts torque to 110 ft. pounds

4. You can now align bore the block. Align bore block initially with a rough cut to 0.010 under finished size. On second pass, align bore to finish size. Align honing not necessary if bore can be done close enough. If not, rough align bore then hone for final finish. Debur and clean as necessary.

Angled and Stepped Main Caps

1. Measure the #2, #3, and #4 cap registers in the block to determine if registers are equal. If not square, square by milling caps. Take the largest reading of the six different readings (both sides of the 3 mains) and mill the other registers, at the point in the block where the bolt holes are to that measurement. With the block registers equal, to get the register depth for the main cap, take the register depth in the block and add 0.001 to 0.003 required side bolt pad clearance. Mill the caps to get that dimension. If the clearance dimension is too big then mill the cap register on the bolt hole pad. If the dimension is too small then mill the outer most pad, make sure not to cut down the vertical register step any. The caps should be milled so the register depth is 0.001 to 0.003 more than the block's register depth. The clearance is critical in that the small air gap gives the cap its bite on the register and stops the caps from walking. A clearance larger than 0.003 will distort the main bearing bores.

2. Repeat step 2 from above.

3. Install the caps on the blocks and tighten the center bolts. Insert bushing into the side hole of the cap. For 3/8” bolts drill block with 5/16” drill bit, for 7/16” bolts drill with 3/8” bit, deep enough for the bolt plus and additional 1/8” clearance. Do not drill to deep or you will drill into the water jacket. Check to be sure bolt will not bottom out in hole. Remove the drill busing and use the cap itself as a tap fixture and tap the threads. For 3/8” tap 16 threads, for 7/16” threads tap 14 threads.

4. Repeat step 3 from above.

5. Repeat step 4 from above.

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