Installation

Here's the engine being painted. The Superior cylinders came from the factory with black paint on the barrels, so I left that as-is and just painted the core engine case. This took quite a bit of masking. If you have a Lycoming, or if you're using overhauled cylinders without paint, I'd recommend just painting everything one color and save yourself the masking effort.



The baffles and air scoops got repaired, acid-etched, Alodined, epoxy primed, and then topcoated with grey Imron for maximum corrosion protection and shine. I have a fetish about corrosion protection so I gave them the full treatment. It is debatable whether this is worth it given that baffles are effectively consumable. Here's the priming step for one load of pieces.




After all the engine work, there's the re-installation on the airplane. This process is a lot cleaner after overhaul, but takes a lot of time due to the many fiddledy brackets, clamps, wires, hoses, and controls to route and secure.



Once the prop is reinstalled you need to set up the engine's internal timing by measuring angles from top-dead center piston stroke on the #1 cylinder. A timing disk attached to the spinner and a piston stopper plug is the most accurate way to perform this task on an O-470. The magnetos are then installed and timed to the engine and to each other so that they fire at the right position for the engine to make power.
Lastly there's finishing details such as the spark plugs, spark leads, P-leads for controlling the ignition, exhaust manifold, baffle sealing strips, carb heat and intake air hoses, and the engine cowling.

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.

Use of safety wire

self-locking nuts-

Self-locking nuts provide tight connections that will not loosen under vibrations. Self-locking nuts approved for use on aircraft meet critical specifications as to strength, corrosion resistance, and heat-resistant temperatures. New self-locking nuts must be used each time components are installed in critical areas throughout the entire aircraft.Self-locking nuts are found on all flight, engine, and fuel control linkage and attachments. There are two general types of self-locking nuts. They are the all-metal nuts and the metal nuts with a nonmetallic insert to provide the locking action. The Boots aircraft nut and the Flexloc nut are examples of the all-metal type. See figure 5-7. The elastic stop and the nonmetallic insert lock nut are examples of the nonmetallic insert type. All-metal self-locking nuts are constructed either of two ways. The threads in the load-carrying portion of the nut that is out of phase with the threads in the locking portion is one way. The second way is with a saw-cut top portion with a pinched-in thread. The locking action of these types depends upon the resiliency of the metal.



Washers-

Finally, a hardware item that is simple. You are likely to encounter only a couple of different types of washers AN960 and AN970. The main purposes of a washer in aircraft installation are to provide a shim when needed, act as a smooth load bearing surface, and to adjust the position of castle nuts in relation to the drilled hole in a bolt. Also, remember that plain washers are used under a lockwasher to prevent damage to a surface.
AN960 washers are the most common. They are manufactured in a regular thickness and a thinner thickness (one half the thickness of regular). The dash number following the AN960 indicates the size bolt for which they are used. The system is different from others we have encountered. As an example, an AN960-616 is used with a 3/8" bolt. Yet another numbering system. If you see "L" after the dash number, that means it is a thin or "light" washer. An AN960C would be - yes, a stainless washer. I can tell you are getting more familiar with the system so I will throw another wrench into the equation - an AN970 washer has a totally different dash number system. I am not even going to tell you what it is. I will tell you that an AN970 is a larger area flat washer used mainly for wood applications. The wider surface area protects the wood.
There are other types of washers. I mentioned lockwashers that are made several different ways. They are often split ring, they are sometimes internal tooth and even external tooth (see Figure 5). You will also find nylon washers and finishing washers that usually have a countersunk head. So, as you can see, washers are not quite as confusing as other hardware even though we can make ft difficult if we wish.

Reassembly

Now for the fun stuff, reassembling. Before doing that, you measure to check limits. Even if the parts are new you measure to make sure the parts are within limits. To measure the case you have to put it together with specified torque but without anything in it. Keep a record of the measurements for later reference
Corrosion-Prevention.
Prior to assembly of subassemblies, all parts should be cleaned to remove all traces of preservative oil and accumulated foreign matter. During assembly, cover all steel parts with a heavy coat of preservative oil. This mixture should be used on all machined surfaces, especially on bearing surfaces, cylinder bores and piston rings. The practive of using plain lubricating oil during assembly is not recommended.

Pre-Lubrication of Parts Prior to Assembly.
Many premature failure of parts have been traced directly to improper pre-lubrication of engine assembly. If parts are not properly lubricated, or an inferior lubricant is used, many of the engine parts will become scored before the engine oil goes through its first cycle and has had a change to lubricate the engine. This, of course, will lead to premature parts failure prior to normal service life, and in some cases, lead to engine failure before normal service hours have been accumulated. It is of utmost importance, therefore, that the following recommendations be adhered to a engine assembly. Consult the latest edition of Service Instruction No. 1059.

Coat the camshaft lobes, face of tappet bodies and rocker tips with lubri-bond (A) or equivalent.
Coat the valve stems and the interior of the valve guides with Texaco Molytex "0" or equivalent.

All other parts should be coated with a mixture of 15% pre-lubricant (STP or equivalent) and 85% SAE No. 50 mineral base aviation grade lubricating oil.

Olite Bushings.
During overhaul cleaning operations it is possible to wash the oil from these bushings; also, if a bushing has been replaced and either reamed or broached, its porosity may be affected. Therefore, before the
bushings are reassembled into the engine they must be impregnated by immersing then for at least fifteen minutes in engine oil that has been heated to 140°F.

It is strongly recommended that all overhaul facilities adapt a firm policy of checking pitch alignment
of bevel gears at the same time backlash is adjusted during engine overhaul.

Oil Seals and Gaskets.
When building up an engine during major overhaul, replace all oil seals and gaskets throughout the engine. For complete replacement sets of seals and gaskets available for these engines, consult applicable parts catalog.

Arbitrary Replacement of Parts.
It is recommended that certain parts throughout the engine be replaced at normal overhaul regardless of their apparent condition. Consult the latest edition of Service Bulletin No. 240 for information on the replacing of parts at overhaul. Included among these are the following:-


All engine oil hose
All oil seals
All gaskets
All circlips, lockplates and retaining rings
Piston rings
All exhaust valves (except Inconel alloy
All exhaust valve retaining keys
Crankshaft sludge tubes (where applicable)
Cylinder fin stabilizers
All bearing inserts (main and connecting
Magneto drive cushions
Stressed bolts and fastenings
Camshaft gear attaching bolts
Connecting rod bolts and nuts
Crankshaft flange bolts
Damaged ignition cable
All laminated shims
Crankshaft counterweight bushings
Piston pin plugs
A.C. diaphragm fuel pumps