6. Immerse the cylinder block for twenty minutes in a
tank of water heated to 180 200 F.
Fig. 5. - Cylinder Block Prepared for Pressure Test
7. Attach an air line to the water hole cover plate and
apply 80-100 psi air pressure to the water jackets and
This method may be used when a large enough water
observe the water in the tank for bubbles which will
tank is available and the cylinder block is completely
indicate cracks or leaks.
stripped of all parts.
8. Remove the block from the water tank. Then
1. Make sure the seal ring grooves in the cylinder bores
remove the plates, seals, gaskets and liners and blow
of the block are clean. Then install new seal rings in the
out all of the passages in the block with compressed air.
grooves (above the air inlet ports).
9. Dry the cylinder liners with compressed air and coat
NOTE: The current blocks have two seal ring
them with oil to prevent rust.
grooves above the air inlet ports of each
cylinder bore Only one seal ring is required,
however. Install the seal ring in the upper
groove, if it is in good condition; if the upper
This method may be used when a large tank for water
groove is pitted or eroded, install the seal ring in
testing is unavailable.
the lower groove.
1. Prepare the block as outlined in Method "A".
2. Apply a light coating of hydrogenated vegetable type
shortening or permanent type antifreeze solution to the
However, before installing the large sealing plate, fill the
water jacket with a mixture of water and one gallon of
permanent type antifreeze.
The antifreeze will
3. Slide the cylinder liners into the block, being careful
penetrate small cracks and its color will aid in detecting
not to roll or damage the seal rings. Install new
compression gaskets and water hole seal rings in the
counterbores in the top surface of the block.
2. Install the plate(s) and water hole covers as outlined
in Method "A".
4. Secure the plate(s) on the top of the block with 5/8 "-
11 bolts and flat washers.
5. Install the water hole cover plates and gaskets on the
sides of the block.
1972 General Motors Corp.