Assembly

Connecting rod.

Assemble two new connecting rod bolts in each connecting rod . Install new bearing inserts in the connecting rod and cap , making sure the tang of each bearing insert enters the locating slot. Assemble each connecting rod and cap, tighten the nuts moderately. Measure the inside diameter of each bearing and check for clearance against the measurements taken previously on the diameter of the crankpin journals. Do not take measurements of connecting rod bearing across the parting of the rod and cap. Take all measurements at 60° from the parting of connecting rod and cap. 7-54. Place the crankshaft on a suitable support on the bench so that all crankpins are free for installation of connecting rods. Disassemble connecting rods after checking bearing ID, thoroughly coat both inserts and the crankpin journals with preservative oil and assemble rods on their respective crankpins. The order of assembly should be such that the numbers stamped on the caps and rods will be down (toward the sump).

NOTE

Connecting rods are marked at manufacture with the part number followed by a letter (A through E) designating weight groups. It is recommended that replacement sets of rods be of the same weight classification. Individual rods may be replaced by a service rod bearing the letter "S". 7-55. The connecting rod bolts are tightened to a specified torque of 480 inch pounds (40 foot pounds).

Crank case.

Place both crankcase halves on a suitable support with the interior of each half facing upward. new bearing inserts in the crankcase making centre that the tang of each insert is fitted into the recess provided in the crankcase.

Place the left crankcase half on a suitable sup the bench with the cylinder pads down. This should be so constructed as to give approximately ches clearance between the crankcase and bench.

Lay the right crankcase half on the bench with the cylinder pads down. Install the governor drive shaft gear where applicable.

A counter bored recess is provided for an oil seal ring at each bolt and stud location. Install a new oil seal ring at the base of each stud.

Piston and cylinders.

See that all preservative oil accumulation on cylinders and piston assemblies is washed off with solvent and thoroughly dried with compressed air. Immediately prior to assembly of piston and cylinder to the engine, space the ring gap and apply a generous coating of oil mixture as described in paragraph 3-39. Apply to inside of cylinder barrel and to piston and rings working the oil mixture around the rings and into groove. Starting with no. 1 cylinder proceed to install as follows:

Rotate crankshaft so that no. 1 piston, when installgroove. ed. will be approximately at top dead center on the firing stroke: this is determined by both tappets of no. 1 cylinder being on the base circle of the cam lobes. Before any attempt is made to rotate the crankshaft support the connecting rods.

Assemble piston on connecting rod with piston number, which is stamped on bottom of piston

head, toward the front of the engine. The piston pin should be palm or hand push fit. If the original piston pin is tighter than a palm push fit, it is probably caused by nicks or slight carbon in the piston pin bore of the piston. If a new piston pin or piston is to be installed, select the pin to give a palm push fit at room temperature of 15 to 20 C. (60 to 70 F.). After piston pin is in place and central-ly located, insert a piston pin plug at each end of the piston pin.

Place a rubber cylinder base oil seal ring around the cylinder base assemble the application piston ring compressor over the top piston rings and install the cylinder over the piston, pushing the piston ring compressor ahead with the cylinder barrel. As the cylinder barrel approaches the crankcase, catch the piston ring compressor as it drops off the piston skirt. When the base of cylinder is seated on crankcase pad, secure the cylinder with 3/8 inch and 1/2 inch cylinder base nuts, tightening the nuts finger tight only.

To assure proper assembly of the crankcase halves and to eliminate the possibility of subsequent loosening of cylinder base nuts, a definite and specific sequence of tightening all crankcase and cylinder base nuts must be followed. Be certain that crankcase halves have been brought together, and fastenings secured as directed in Section 7 before installing cylinders. The cylinder base hold-down nuts are installed as described in the following paragraphs.

When all cylinders have been initially installed on the crankcase as described in paragraph 5-81, begin

tightening all cylinder base nuts as described below, using the proper cylinder base nut wrenches and handle in conjunction with a suitable torque indicator. Torque wrenches should employ the flexible beam design hydraulic principle or a dial indicator with rack and pinion.

NOTE

Before installing cylinder hold-down nuts, lubricate crankcase through stud threads with any one of the following lubricants, or combination of lubricants.

1. 90% SAE 50W engine oil and 10% STP.

2. SAE 30 oil.

3. Fel-Pro Food Grade AA Anti-Seize Lube.

a. Tighten 1/2 inch hold down nuts to 300 inch pounds (25 foot pounds) torque.

b. Using the same sequence, tighten the 1/2 inch nuts to 600 inch pounds (50 foot pounds).

c. Tighten the 3/8 inch hold down nuts to 300 inch pounds (25 foot pounds) torque. Sequence is optional.

d. As a final check hold the wrench at the correct torque, tapon each nut for about five seconds. If the nut does not turn, it may be presumed to be tightened to correct tor-que.

After all cylinder base nuts have been tightened, remove any nicks in the cylinder fins by filing or burring.

Install some type of vented plug in each spark plug hole after assembly of cylinder to prevent entrance of foreign matter and at the same time to permit the engine to be turned easily by hand.

Install hydraulic lifter in crankcase.

Assemble new shroud tube seal on both ends of shroud tubes.

Parallel Cylinder.

Install each shroud tube through its hole in the rocker box and press to firmly seat the seals in their respective position in the cylinder head and crankcase. Install shroud tube spring , lockplate , and 1/4-20 plain nut over stud provided in the rocker box. Tighten nut to proper torque and secure by bending the lockplate up around the nut.