VALVE COVER

required. Do not pry on contact surfaces. Remove and

(1) Insert feeler gauge (0.007 inch on intake

discard head gasket.

valves and 0.010 inch on exhaust valves) between

b. Cleaning.

tappet adjusting screw and valve stem cap.

(1) Soak cylinder head in SD.

Dry with

(2) Hold tappet with 9/16 inch end of one

compressed air and clean rags.

tappet wrench, and turn adjusting screw with 1/2 inch

(2) Scrape carbon from inside of combustion

end of second wrench until feeler gauge fits with slight

chamber area with carbon scraper, or use a wire brush.

drag. Repeat for all valves.

Do not scratch surface when scraping.

d. Restore engine to operating condition by

(3) Scrape or brush gasketed surface to

reversing b. and a. above.

remove gasket paste residue.

c. Installation. Reverse a. above, using new

6-78. GEAR COVER.

gaskets.

a. Removal.

Tighten head bolts to 100 foot pounds torque.

(1) Remove radiator, disconnect governor to

carburetor control rod hooked to governor lever.

6-76. VALVE COVER. The engine has two valve

(2) Remove governor attaching screws and lift

covers. These covers are removed for valve service, or

governor away from gear cover.

replacement of the gaskets.

(3) Remove hydraulic pump (paragraph 6-29).

a. Removal.

(4) Remove starting crank grab and fan drive

(1) Remove tube from rear valve cover to

pulley.

crankcase ventilating check valve.

(5) If engine is in vehicle, remove front motor

(2) Remove two screws holding each cover in

support screws. If necessary to raise front of motor to

place and lift off valve covers with cover gaskets.

release the front support, use a large block of wood

Discard gaskets.

under front of oil pan so jack will not damage it. The

b. Installation. Reverse procedure in above, using

front support may be removed from the gear cover, if

new gaskets.

necessary.

(6) Remove gear cover attaching screws

6-77. VALVE ADJUSTMENT.

(Figure 6-31) and pull gear cover forward away from the

a. Remove valve covers (paragraph 6-76).

engine. The crankshaft oil seal will pull off the shaft with

b. To the extent necessary to provide

the gear cover. If no gasket or seals are available, use

working room during valve adjustment, disconnect the

care when removing these parts.

following items: (1)

Air duct (at carburetor).

b. Installation.

(2) Throttle, choke, and governor linkages (at

(1) Wash and clean the gear cover and fasten

carburetor).

a new gasket to the gear cover with gasket cement.

(3) Fuel line (at fuel pump intake), and fuel

Loosen thrust screw lock nuts and back screws out two

line from fuel pump to carburetor (remove completely).

or three turns.

(4) Fuel pump (remove two capscrews and

(2) Carefully install the oil seal on the

washers, and remove pump).

crankshaft and slide the seal about one inch back on the

c. Crank engine by hand until D-C mark appears at

shaft. If available, use new seal and ring.

hole in flywheel housing. At this time both valves will be

(3) Assemble the gear cover on the seal. Use

open (tappets cannot be turned with fingers) at No. 1

care that the seal properly seats in the groove provided

cylinder, and both closed at No. 6 cylinder or vice versa,

for it in the gear cover.

depending on whether No. 1 or No. 6 piston is in firing

(4) In order to avoid any difficulty with the oil

position. If No. I valves are open, adjust valve clearance

seal sleeve when pushing the gear cover back in place,

on cylinders 3, 2 and 6, then turn the engine one full

loosen the oil pan and allow the front end of the oil pan to

revolution and adjust valves for cylinders 1, 5 and 4, as

drop 1/8 inch to 1/4 inch. Then push the gear cover back

follows:

into place.

(5) Check to see that oil seal sleeve is

properly located in the oil pan.

104