Figure 5. 3/4 front, left side of engine, installed view

(5) T W O adjacent low-reading cylinders

compression pressures at cranking speed is

l10 to 120 pounds (psi).

indicate a defective cylinder head gas-

ket.

h. Retest low-reading cylinders using the

oil test as follows:

19. Engine Assembly Vacuum Test

(1) Add oil through the spark plug suf-

To perform a reliable vacuum test, start

ficiently to seal the piston rings.

e n g i n e and let it idle until it reaches normal

(2) Crank engine five or six times to allow

o p e r a t i n g temperature. Proceed with test as

o i l to work down around the rings,

follows:

t h e n take another compression read-

ing.

a. Stop engine when normal temperature has

been reached, then remove intake manifold plug

(3) An increase in compression indicates

(fig. 9) and install a vacuum gage.

defective or worn piston or rings.

(4) No increase in compression indicates

b. Start engine and observe the vacuum gage.

defective valves.

Analyze the gage readings as follows:

AGO 6217A