|
|
AERONCA Engine Handbook Table of Contents Previous Section Next Section Index Home
PART V - COMPLETE OVERHAUL - Continued
O-1. Crankshaft and Connecting Rod Assembly #718 (Needle Roller
Connecting Rod Bearing
The overhauling and refitting of the connecting rod bearings on this
assembly should only be done at the factory unless proper tools and
facilities are available. This crankshaft assembly supersedes #358
and is used on all AERONCA E-113B engines.
The crankshaft and connecting rod assembly should be held in a
horizontal position while being overhauled. See Remarks under
Section N-1, Part V - COMPLETE OVERHAUL for method of holding
crankshaft and removing connecting rod nuts. It is most important
when removing a connecting rod from the crankshaft to place a clean
pan or rag underneath the connecting rod to catch the needle rollers
as the cap is removed. It is very important that there be exactly
fifty needle rollers in each assembly and they must not be inter-
changed between bearings.
Examine all parts very carefully for cracks and worn places and clean
out all of the oil lines in the crankshaft. The three oil plugs can be
removed and it is best to blow out the oil lines from the front crank-
pin hole so that any dirt will be removed through the large rear hole.
An oil gun filled with gasoline will work very satisfactorily. The oil
plugs should be restaked after assembly.
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 small pin through the side of the bolt head.
If it is necessary to tighten the counterweight, punch out the safety
pins with a small drift punch and remove the bolts using a 5/16" hex
wrench. If the counterweights are found to be loose, it is best to
replace the counterweight bolts, Part #689. After the counterweights
have been refitted and the bolts tightened, re-drilled the bolt heads
and safety each with a piece of cold rolled steel rod, peening both ends.
O-2. Assembly of Connecting Rod Needle Bearings on No. 718 Crankshaft
and Connecting Rod Assembly. (See Figure 13)
After all parts have been thoroughly cleaned, the counterweights
refitted, if necessary, and the main bearings checked with their outer
races, then the connecting rod needle bearings are ready to be fitted.
Each connecting rod bearing requires fifty needle rollers, Part #715.
These rollers can be obtained from the factory in the following sizes:
standard, (.1240") and plus or minus .0002". A running radial clear-
ance of not over .0010" is desired; however, a minimum of .0005" must
be maintained. The radial clearance of this type of bearing is not
nearly as critical as that on the connecting rod bearings used in the
former crankshaft assembly, Part #358, and much greater radial clear-
ances can be tolerated. For this reason it will probably be found
possible to install new needle rollers of the same size as were
previously in the bearings. The original size of needles in the
bearings can be obtained from the factory, if the engine is a new
one by advising the serial number of the engine.
When reassembling the connecting rod bearing be very careful to see
that each connecting rod is placed on the same crankpin from which it
was removed. It will be seen on Figure 13, at the rear of the book,
that the projection or the wrist pin boss on the connecting rod is
toward the center of the engine. It is very important that the
connecting rod be placed on the crankshaft in this manner, otherwise
there will be some interference with the piston.
When installing the connecting rod it has been found best to hold the
crankshaft horizontally. After lightly coating the connecting rod
bearing with a good grade of grease, approximately twenty-five needle
rollers may be laid on the connecting rod bearing when held vertical,
and by slowly raising the connecting rod to the crankpin they will
remain in place.
The upper half of the crankpin may now be coated with grease and the
remaining needle rollers laid in place after which the cap can be
slipped over the connecting rod bolts and the nuts tightened. Do not
back up the nuts in order to safety them with cotter pins, but remove
the nuts and grind a slight amount from the bottom to get the cotter
pin holes to line up.
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. When rotating the connecting
rods, they may appear to bind and drag; however, if a slight amount
of pressure is applied radially inward toward the crankpin they will
be found to turn very easily.
The connecting rods should be very little side motion out at the wrist
pin bushings when new needle rollers have been installed. However, it
is important that the connecting rods are properly aligned. This can
be checked by swinging both connecting rods until the wrist pin holes
line up; then a piston pin should be inserted through both holes. If a
considerable force is required, it usually indicated a bent rod or
improperly aligned bushings.
0-3. Crankshaft and Connecting Rod Assembly #750 -
Plain Bearings on Crankshaft
The overhauling and refitting of the connecting rod bearings on this
assembly should be done at the factory unless proper tools and
facilities are available. This crankshaft assembly supersedes #718
and will be used as a replacement unit in the field on all other
AERONCA engines.
Those plain bearings can only be used on the No. 687 crankshaft which
has 1/870" diameter crankpins (nominal). This includes all of the
needle bearing crankshaft assemblies as used in the E-113B engine and
any other needle bearing assemblies installed in the E-113A engine.
These plain bearings will not fit on the small pin crankshafts which
were standard in the E-107A, E-113, and E-113A engines.
The crankshaft and connecting rod assembly should be held in a hori-
zontal position while being overhauled. Examine all parts very care-
fully for cracks and worn places and clean out all of the oil lines in
the crankshaft. The three oil plugs can be removed and it is best to
blow out the oil lines 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. The oil plugs should be
restaked after assembly.
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 small pin through the side of the bolt head.
If it is necessary to tighten the counterweight, punch out the safety
pins with a small drift punch and remove the bolts using a 5/16" hex
wrench. If the counterweights are found to be loose, it is best to
replace the counterweight bolts, Part #689. After the counterweights
have been refitted and the bolts tightened, redrill the bolt heads and
safety each with a piece of cold rolled steel rod, peening both ends.
0-4. Assembly of Connecting Rod Plain Bearings on No. 750
Crankshaft and Connecting Rod Assembly. (See Figure 14)
After all parts have been thoroughly cleaned, the counterweights
refitted, if necessary, and the main bearings checked with their
outer races, then the connecting rods are ready to be installed.
1. TWO SIZES OF PLAIN BEARINGS AVAILABLE -
STANDARD O.D. AND + .025 O.D.
The plain bearings are available in two sizes of outside diameter;
one made with a standard O. D. And the other with a + .025 O.D.
for those connecting rods from the E-113B engines which must be
reground.
As the plain bearing shells are held in place by two small notches
in the connecting rod, it is necessary to alter the connecting rods
from the E-113B engines before they can be used with plain bearings.
This must be done at the factory. It now possible to exchange the
E-113B connecting rods for a set of reconditioned connecting rods
which have new piston pin bushings and plain bearings fitted.
In this way the servicing of the bearings in the field will be
greatly simplified. It is necessary when ordering replacement
plain bearings, to advise the factory of the number stamped on the
rear of each bearing shell of the old plain bearings that were in
the engine. It is also advisable to give the maximum and minimum
diameters of each crankpin. For all needle roller crankshaft
assemblies, the crankpin diameter will not have worn sufficiently,
in most cases to make any real difference in the size of the plain
bearings required, so that in converting from the E-113B to the
E-113C engines standard I.D. bearings will be furnished.
2. OIL CLEARANCES IN BEARING When fitting the plain bearings to the crankpins, and oil clearance
of .0008" to .0018" is desired. It is best to favor the lower limit
as this will give the greatest amount of service between overhauls.
It is recommended that the crankshaft assembly be sent to the
factory for the fitting of plain bearings as the proper size
bearings can then be selected for the crankshaft.
3. REGRINDING OF CRANKPINS When crankpins have worn .001" to .0015" out of round and/or .0005"
taper, it will be necessary to have the crankshaft reground to one
of the sizes listed on this memorandum, which will be a multiple
of .010". This should be done at the factory where proper facilities
are available.
4. CORRECT LOCATION OF BEARING SHELLS It is very important when installing the bearing shells in the
connecting rods that the bearing marked "U" (which is a plain shell
without any oil holes) be placed toward the shank or upper end of
the connecting rod. The bearing marked "L" (with oil grooves) is
intended for the cap side of the rod. When they are installed in the
rods be sure that they fit solid, and do not, under any circum-
stances, file either the rod or bearings at the split joint as the
bearings are made to fit properly in the rod as originally machined.
It is important to pull up tight on the two connecting rod bolts as
this will give the bearing shells the proper compression at the joint.
Clean out all lines in crankshaft before assembling connecting rods. 5. LIST OF PLAIN BEARINGS AVAILABLE - ORDER BY NUMBERS
A - Standard O.D. Bearings - For Use in #760 Con Rods (New)
For Use With Nominal
Bearing Bearing Crankpin Crankpin
Part No. I.D. Diameters Size
B-146-9 1.8710" 1.8702" to 1.8692" Std.
B-146-10 1.8700" 1.8692" to 1.8682" Std.
B-146-13 1.8610" 1.8602" to 1.8592" -.010 Reground
B-146-14 1.8510" 1.8502" to 1.8492" -.020 Reground
B-146-15 1.8410" 1.8402" to 1.8392" -.030 Reground
B - Plus .025 O.D. Bearings - For Use in #760-1
Con Rods (Reconditioned)
B-146-11 1.8710" 1.8702" to 1.8692" Std.
B-146-12 1.8700" 1.8692" to 1.8682" Std.
B-146-16 1.8610" 1.8602" to 1.8592" -.010 Reground
B-146-17 1.8510" 1.8502" to 1.8492" -.020 Reground
B-146-18 1.8410" 1.8402" to 1.8392" -.030 Reground
6. FOR INSTRUCTIONS ON CONVERTING THE E-113B ENGINE
TO THE E-113C TYPE, WRITE THE FACTORY FOR
MEMORANDUM NO. M-3.
7. FOR INSTRUCTIONS ON INSTALLING THE PLAIN BEARING
CONNECTING ROD AND CRANKSHAFT ASSEMBLY IN ANY OF THE
AERONCA E-107A, E-113 AND E-113A ENGINES, WRITE THE
FACTORY FOR MEMORANDUM NO. M-4
|
|
|
