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AERONCA Engine Handbook Table of Contents Previous Section Next Section Index Home
PART V - COMPLETE OVERHAUL A complete overhaul should not be required before 250 to 275 hours of hard service. However, unusual indications...such as excessive oil consumption or the find of metal particles in the engine oil...may show the need for examination before this time. (This is one of the reasons why it is important that the old oil should be strained at each oil change. SECTION 1 - FACTORY OVERHAUL The Aeronautical Corporation of America maintains a complete engine assembly plant and test stand at its factory at Cincinnati, Ohio. All of the work is done by expert mechanics who are thoroughly familiar with the overhaul, assembly and testing of AERONCA engines. To assure that the engine will receive the best of care and competent workmanship, we strongly recommend that a complete overhaul be done only at the factory. The charges for this service are moderate and the transportation cost is not excessive inasmuch as the shipping weight of the engine is approxi- mately 200 lbs and the factory is centrally located. Standard engine shipping boxes may be obtained at a nominal cost. For further information, write the factory. The factory should be notified in advance of shipment so that prompt service can be rendered. SECTION 2 - COMPLETE DISASSEMBLY To disassemble an engine completely, it must be removed from the plane. Remove the propeller using the propeller hub puller (Tool No. T-11), (on E-113C engines the locking nut acts as a puller) the exhaust pipe, gasoline, tachometer and all gauge connections. Remove the two lower mounting nuts being careful to support the engine as the top mounting nut is removed. The engine may be lifted out of the plane by two people very easily as it weighs only slightly more than 100 lbs. Place the engine on an assembly stand (Tool No. T-10). The exterior of the engine should be thoroughly cleaned with gasoline before any work is undertaken. A clean workshop is essential for a good complete overhaul job and a number of clean cans or boxes should be provided for the small parts. CAUTION: Always use a fiber drift or mallet whenever it is necessary to
separate or drive parts together. This procedure will prevent
damage to the engine parts.
A. Removing Cylinders Remove the cylinders and disassemble the parts as explained under
Part IV - TOP OVERHAUL.
B. Removing Pistons To remove the pistons it is necessary to remove one of the snap rings
which hold the piston pin in place. ; A narrow screw driver can be used
to snap the ring out of place. If the piston pin is tight in the piston,
heat the piston slowly with a blow torch unit the pin can be removed.
If the pins are very loose, they should be replaced with .005" over-
sized pins. For this oversize pin, the piston pin holes should be
carefully reamed to 1.0050" plus .005" minus .0000" and the connecting
rod bushing to 1.0058" plus .0005" minus .0000". New standard or
oversize pistons and pins will require the pistons to be heated to
approximately 212 F. (Temperature of boiling water) before they can be
assembled. It is necessary that the pin be a tight fit in the piston
and a push fit in the connecting rod bushing. (See Table of
Clearances, also Section 3-E, Part V - COMPLETE OVERHAUL.)
C. Disassembly of Accessories Remove the magneto, intake manifold, breather, oil filter, and oil
lines, tachometer shaft and bushing, oil pump and gear cover. (See
Figure 5)
Before removing any of the gears be sure they are marked so that they
will be replaced in their correct positions. (See Figure 7) The gears
should mate as shown on this figure. However, the engine may have been
retimed since it was originally constructed and new marks should be
placed on the gears so that they will be correctly assembled, if the
old marks do not line up. The oil pump idler and camshaft gears can
now be removed.
Remove the propeller hub key and the front plate from the engine then
the thrust bearing lock nut, using tool No. T-14. It will be necessary
to place a piece of wood or fiber through one of the connecting rod
bushings in order to keep the crankshaft from turning while the thrust
nut is being removed. Carefully remove the back plate which contains
the outer race of the rear main bearing and the oil relief valve and
overflow tube which may be left attached to it.
Remove the oil level gauge by grasping the rod with a pair of pliers
and giving it a quick jerk. The cork float will remain in the oil
reservoir and should be cleaned before being used again.
To remove the crankshaft assembly turn the crankshaft until the two
crankpins are horizontal and in normal position of B. D. C. The entire
assembly can then be removed through the rear of the crankcase. The
thrust bearing will remain in the crankcase and can be removed from
the front end in order to inspect and clean it.
It should not be necessary to remove either the camshaft assembly
or the cam followers. However, if they must be replaced, the cam
followers can be removed by using Tool No. T-16. It will be necessary
to heat the crankcase around the cam followers before they can be
removed. The camshaft is removed by driving it out of the crankcase
from the front end after the camshaft cover and locking set screw
have been removed. See that the cams do not strike the follower rollers.
SECTION 3 - INSPECTION AND REPLACEMENT OF PARTS After disassembly, all parts should be thoroughly cleaned and laid out in groups on a clean bench for inspection. As the parts are examined make a list of all defects and all parts that are to be replaced. The correct clearances for the various parts are shown in Figures 5 and 6. A. Cam Followers The follower must slide freely in its guide within the specified
clearances. Should the rollers show signs of wear or excessive
clearances, the roller and pin, or the entire plunger assembly,
should be replaced.
B. Push Rods The ball ends must be tight on the push rod and must be smooth and
not show any wear.
C. Camshaft Assembly The camshaft should be examined for wear on the cam surfaces. If they
are badly worn or chipped the camshaft should be replaced. The two
camshaft bearings should turn freely.
If it is necessary to remove the camshaft, see Section 2-C,
Part V-COMPLETE OVERHAUL.
D. Cylinder Assembly Examine all cylinder parts, following the instructions given in
Part IV, TOP OVERHAUL, for the particular engine being overhauled.
It is advisable to replace the exhaust valves and all valve springs
after 450-550 hours of service.
Should it be necessary to replace a valve guide, it can be accomplished
in the following manner:
First, tap the guide from the outside for a distance of approximately
1-1/4". Use 3/8" - 24 S.A.E. tap for the E-113 intake guide and a
7/16" - 20 S.A.E. tap for the E-113 exhaust guide and both intake and
exhaust guides on the E-113A, B and C engines.
Heat the cylinder head to approximately 250 F. Around the guide and
use Tool No. T-17 for removing the E-113 intake guide and Tool No.
T-18 for removing the E-113 exhaust, E-113A, B, and C intake and
exhaust guides.
Examine the hole in the head to see that it is clean and smooth, also
examine the new guides for burrs. New guides should be covered with
white lead and put in immediately after the old guide has been removed.
In this way it will not be necessary to re-heat the head. Be careful
not to damage the guide when driving it into place. Use Tool No. T-19
for driving in the E-113 intake guide and Tool No. T-20 for the E-113
exhaust and both of the E-113A, B and C guides.
To change guides in the E-107A cylinders, use the same procedure and
tools as for the E-113A, as explained above, except do not heat the
cast iron cylinder as it is not necessary.
Examine the rocker arm shaft bushings in the E-113A, B and C heads.
If they show signs of wear in the head or on the shaft, they must be
replaced with oversize bushings. It will be necessary to ream the
aluminum head before inserting an oversize bushing. These bushings can
be furnished oversize plus .005", .007", and .010" on the O. D. The
aluminum head should be reamed to .003" less than the replacement
bushing O. D. When replacing these bushings into the head against the
rocker arm which is held in place by the end of the shaft and the
center bushing. This will have to be done rather rapidly as the cold
bushing will cause the aluminum head to contract. The bushing will
then have to be reamed for the shaft.
Examine the rocker boxes on the E-113 cylinders to see that they are
tight and show no signs of wear on the head. If they are found to be
loose, they must be removed. This work should be done at the factory;
however, if it is absolutely necessary to do it in the field, follow
the instructions given below:
Remove the rocker arm and the two nuts which hold the box in place.
It is very important that the rocker box be "lapped" to the head in
order that the bearing load will be distributed over the entire area.
Fine grinding compound should be used an the fit should be checked
with Prussian Bluing. When reassembling to be sure all parts are
thoroughly clean and be careful when tightening the stud nuts which
hold the rocker box in place as it is possible to loosen a stud in
the soft aluminum alloy head, if too much force is applied.
Should it be necessary to remove the head, from the barrel, we
recommend that the entire cylinder assembly be returned to the factory
for this work as it is rather difficult to remove the head without the
proper tools and facilities.
E. Pistons, Pins and Rings The pistons should be carefully cleaned and examined. The piston pin
should be tight fit in the piston at room temperature (70 F). If the
pin is looser than .0005" in the piston, it should be replaced with
a .005" oversize pin in which case the piston pin hold should be
carefully reamed to 1.005" plus .0003". It will also be necessary to
ream the connecting rod bushing to 1.0058" plus. .0005" minus .0000".
If the pistons are badly scratched or the ring grooves worn, a new
piston should used. If the ring grooves are in good condition and the
piston is slightly scratched, it may be smoothed up by using Crocus
Paper dipped in kerosene or a fine oil stone which will give a very
smooth finish.
It is desirable to use new piston rings when completely overhauling
the engine. These should be fitted in the cylinders so that they do
not have over .012" end clearance. The new rings should fit freely in
the ring grooves of the piston.
Pistons for the E-107A engine are furnished in standard, plus .005"
and plus .020" oversize, and can also be furnished semi-finished.
Pistons for the E-113, E-113A, B, and C engines are identical and can
be furnished in the following sizes; standard, plus .005", plus .010",
plus .015", plus .020", plus .025". It is not advisable to bore the
steel cylinders to more than plus .025" oversize as the wall will be
too thin for safety.
The last 1934 E-113A, and all E-113B and C engines, use a new type
piston. This piston, Part No. 733, has two Part No. 737 1/8" com-
pression rings and one Part No. 442 oil ring. This piston supersedes
the former piston Part No. 426 which had three Part No. 441 3/32"
compression rings and one Part No. 442 oil ring.
The new type piston has a longer skirt length due to the fewer com-
pression rings and has only .016" skirt clearance in the cylinder.
Piston rings can be furnished for any of the piston sizes listed
above. The gap clearance should be at least .012".
F. Crankcase The crankcase is made from one casting. The front main bearing race
should be examined to see that it fits tightly in the crankcase. The
same is true of the rear camshaft bearing and front thrust bearing.
It is important to check the clearance between the flange on the front
plate and the outer race of the thrust bearing with a depth micrometer.
This can also be accomplished by assembling the front plate to the
crankcase (using the gasket) after the crankshaft has been removed,
and checking the clearance by means of a feeler gauge. (See below)
This clearance should not be over .008". If it is greater than this, a
thinner gasket should be used on the front plate to bring this clear-
ance down to approximately .001". (See Figure 5) Any excessive clear-
ance may be due to wear of the inner thrust bearing retaining ring
(Part No. 310) which can be inspected by removing the thrust bearing.
The entire crankcase should be thoroughly cleaned out, using gasoline
and a brush or compressed air, so that all of the oil sludge and other
foreign matter is removed. This is very important.
G. Backplate Check the fit between the outer race of the main bearing and the
backplate. This should be a tight fit. The idler gear spindle should
be tight in the backplate and should be a good fit in both the gear
and the magneto driver.
The oil relief valve should be taken apart by unscrewin the large cap
at the rear of the valve and all of the internal parts thoroughly
cleaned and checked for wear. The old tube should also be cleaned out.
H. Gears Inspect all gears for worn and chipped teeth. The back lash on the
gear train should be between .003" and .006".
I. Gear Cover Examine the oil inlet spindle to see that it is screwed tight (L.H.
thread) into the oil inlet cap (See Figure 5). The fit between the oil
inlet spindle and bushing in the crankshaft gear should not be over
.004" loose. The collar and spring should be in good condition. A
safety lock (Part No. 714) prevents the spindle from rotating loose.
The magneto driver should turn freely in the bearing in the gear cover.
If there has been any oil thrown out through this bearing, it is
advisable to replace the felt cup packing.
Examine the tachometer shaft and bushing for wear and examine the
screw driver end of the shaft which fits into a slot in the end of the
camshaft. A spanner wrench, tool No. T-6, can be used to remove this
bushing.
J. External Oil Lines Clean out all fittings and oil lines and examine the small bushing
(Part No. 438) in the oil line to see that it is clear. (See Figure 5)
(Note: This bushing is omitted on all engines using the Cuno oil
filter installed and all E-113C engines)
K. Breather Assembly The breather assembly consists of three parts - a flapper valve
(Part No. 417), a breather body, Part No. 397 and a return oil line
with ball check valve (Part No. 427). Examine the flapper valve to see
that it is operating properly. If it shows signs of wear, the part
should be replaced. The breather body should be cleaned out and, if
oil has been escaping from the top of the breather, a new cork gasket
should be used. If the inside baffle of the breather is a casting as
shown in Figure 5, it is advisable to replace it with Part No. 645
which is of a later design and much more efficient. The oil return
line and the ball check valve should be cleaned.
L. Oil Pump Assembly The oil pump is disassembled by removing the four screws which hold
the inner cap to the cover. Examine the gears for wear, also the
bearing surfaces. The entire pump should be thoroughly cleaned. It
may be necessary to "lap" the three castings together in order to
obtain a good fit when assembling the pump. Oil all parts generously,
and, after safetying the four screws with brass wire, turn the pump by
hand to see that it is free in both directions. It should turn easily.
M. Intake Manifold The intake manifold on the E-107A engine is a single casting and
should be examined for cracks and sand holes. The manifold on the
E-113, E-113A, B, and C engines are very similar and consist of the
three castings, a center U section and right and left elbows. If the
hose connections are in bad shape or deteriorating, it is best to
replace them. The E-113 elbows are not interchangeable with the
E-113A, B, or C.
N-1. Crankshaft & Connecting Rod Assembly #358 (1/4" Connecting Rod
Rollers with Cage)
The overhauling and refitting of the connecting rod bearings of the
crankshaft assembly is a very particular job and should only be done
at the factory unless proper tools and facilities are available for
this work. It is most important that this work be done very accurately
as the time between complete overhauls depends a great deal on how
well this work is done and it is for this reason that we strongly
recommend that the crankshaft and connecting rod assembly be sent to
the factory for overhaul.
The crankshaft and connecting rod assembly should be held in a
horizontal position while being overhauled. An old propeller hub is
ideal for this purpose as the flange can be clamped in a vise and the
crankshaft mounted in it, using the propeller hub nut as a safety.
However, if the hub is not available, the crankshaft may be clamped
between soft jaws in a vise. It is best to hold the shaft between the
front thrust bearing and the front main bearing. To remove the
connecting rods, use a socket wrench, preferably one which has the
socket beveled at approximately 30 , and remove the two connecting
rod nuts (See Figure 6). Keep all the parts for each bearing separate
so that they will not be interchanged when reassembled.
Examine all parts very carefully for cracks, wear, galled surfaces,
etc. A slight galled spot on either the connecting rod or crankshaft
may be stoned down, preferably by using a small piece of Crocus Cloth
dipped in kerosene or a fine oil stone. It is only necessary to
undercut the galled spots a very slight amount (.0003"). This should
stop any further galling from this spot.
Clean out the oil lines in the crankshaft. It is best to first blow
out the oil line from the front crankpin hole so that any dirt will
be removed through the large rear hole. An oil gun filled with
gasoline will work very satisfactorily.
Check the counterweights to see that they are tight by tapping them
with a small hammer. Do not try to tighten the counterweight BOLTS AS
THEY ARE SAFETIED WITH A PIN THROUGH THE SIDE OF THE BOLT HEAD. If it
is necessary to tighten a counterweight, punch out the safety pins
with a small drift punch and remove the bolts. Examine the bolts very
carefully for any cracks especially in the thread section. It is
desirable to use new bolts (Part No. 713 - was #262-2) if it is
necessary to refit the counterweight. Replace counterweights, tighten
bolts, re-drill bolt heads and safety each with a piece of cold
rolled steel rod, peening both ends.
N-2. Assembly of Connecting Rod Bearings on No. 358 Crankshaft and
Connecting Rod Assembly (1/4" Rollers with Cage)
After all parts have been thoroughly cleaned, the counterweights
re-fitted, if necessary, and the main bearings checked with their
outer races, then the connecting rod bearings can be fitted.
Each connecting rod bearing required 20-1/4" diameter rollers
(Part No. 340). These rollers can be obtained from the factory in
steps of plus or minus .0002" from the standard size of .2500",
and it is very important that the correct tolerance roller be used.
A running clearance of not over one thousandth of an inch (.0010")
should be maintenance. The following procedure should be used to
determine the correct tolerance of roller to be used in each bearing.
1. Micrometer each crankpin, using a micrometer having a ten-
thousandth vernier scale.
2. Micrometer each connecting rod, using an internal micrometer
having a ten-thousandth vernier scale.
3. Follow the example given below:
Connecting rod, #1, bore - 2.1800"
Crankpin, #1, diameter - 1.6800"
Difference 0.5000"
Deduct maximum running
clearance at 0.0010"
Twice diameter of roller
required 0.4990"
Diameter of roller required - 0.2495"
Diameter of roller required - 0.0005" undersize
Use - .0004" undersize rollers. This will give a
running clearance of .0008" which will be
satisfactory.
4. Check each crankpin and rod as one bearing may require a
different tolerance of roller than the other.
5. Place the new rollers in the retainers with the rounded ends
toward the center cheek of the crankshaft, as shown below:
VERY IMPORTANT
6. If the inner corners of the retainer have been riding on the
crankpin radius, grind off a slight amount on each projection.
(See Figure on previous page.)
7. When assembling, draw up on the connecting rod bolt, slowly,
making sure that the connecting rod does not bind. If it binds
when the rollers are too large, (See No. 9 following)
8. Draw bolts tight - do not back up nut in order to safety with
cotter pin but remove nut and grind a slight amount from bottom
to get cotter pin holes to line up.
9. Check the Assembly (a) With the crankshaft in a horizontal position, each connecting
rod should fall freely from a horizontal position and even
oscillate a slight amount before coming to rest.
If they will not do this, then the rollers are too large
and the next smaller size should be tried. If the large
rollers are used, serious damage may result to the
crankshaft and connecting rods.
(b) The connecting rods should rotate freely while being
turned through five or six continuous revolutions in one
direction. Check this in both directions.
(c) The connecting rods should not have over .025" side motion,
measured out at the wrist pin bushings. More play than this
usually indicates too small a roller, or worn rollers.
(d) The ideal condition is little or no shake at the wrist pin
and free falling rod.
(e) Check the connecting rod alignment by swinging both rods
until the wrist pin holes are lined up, then insert a wrist
pin through both. It should be a snug fit. If a considerable
force is required, it usually indicates a bent rod or
improperly aligned bushings.
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