Found this in this month's Auto Restorer magazine... Good article.
-Dave
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Mopar 318 A-series V-8
Not Detroit's Most Exciting Engine But it's Versatile, Hard-Working and
Built to Last
BY THOMAS MURPHY
FIRST OFF, LET'S clear up a slightly murky area when it comes to
318-cubic-inch engines. Chrysler built two different 318s, the A engine
and the LA engine. The one we will meet today is the A engine, built
from 1956 through 1966. The LA engine was inaugurated in 1967 and is
still to be found under the hood of 1998 trucks as a 5.2 liter.
Some people tend to overlook the 318 because it doesn't have the
performance image of some of its bigger brothers, such as the 383 and
the 440. But, the 318 has more than enough power to move a mid- or
full-size car through any traffic conditions and it's been known to spin
a tire or two in its day as well.
The 318, moreover, probably will still be coming off an assembly line in
another 30 years in one guise or another, mostly because it's one very
good engine. Not only is it fairly good on gas-around 18 mpg when the
accelerator pedal is pushed lightlybut it also seems to be well nigh
indestructible. I know first hand, 'cause I sure tried to blow one up.
Once upon a time (No, this isn't a fairy tale--they have happy
endings.), I had the rare experience of processing through a Dodge
agency and issuing out the other side with a brandnew 1966 Charger
replete with a 318 2-barrel engine. Boy, was I cool or what? I was 21
years old and had no more business buying a new car than trying to fly
by flapping my arms. I signed for the grand sum of $4200 ($500 down
payment financed through Household Finance) and took possession of the
Charger.
I wasn't real smart about maintenance back then (Don't say it-I have
learned a little in the meantime.), and pretty much thought the engine,
being new, would run forever without any personal attention from me.
This included totally ignoring the dipstick for the first 3000 miles.
I proceeded, dumb and happy; driving the car like any young man would.
Occasionally I even took my foot off the floor and let the engine
breathe a bit, but mostly it was flat
out all the time. When the odometer reached about 3400 miles, the engine
started to make funny noises. I kinda figured it was just breaking in,
so I ignored the clacking emanating from under the hood. Another 400
miles and the car told me it had had enough-right in the middle of an
intersection. Time for a tow truck.
Two days later, the dealer called and made rather rude noises in my ear
about my flagrant lack of knowledge when it came to maintenance. It
seems that when they pulled the drain plug, just about enough oil came
out to lubricate a Swiss Army Knife.
To make a long story short, the dealer agreed to replace the bearings,
lifters, cam, etc. Linder warranty providing I brought the car by every
500 miles for an oil check. A sadder and wiser man I became.
Some History
The 318 has proved to be one of Chrysler's most popular and reliable
engines. It began life as a stretched 277-cubic-inch V-8 that carried a
3.75 inch bore and 3.12-inch stroke. The engine first grew to a
301-cubic-inch displacement and went to 318 cubic inches in late 1956
when it received a 3.91-inch bore and 3.31-inch stroke.
The most powerful of these early 318s went into the 1957 Plymouth
Fury-producing 290 horsepower while breathing through dual 4-barrel
carbs. The normal bread-and-butter 2-barrel version of the 318 produced
230 horsepower and the 4-bbl motors put out 260 horsepower from 1958 to
1962. The 1959 Dodge "Red Ram" 325 engine also was part of the "A"
family, directly related to the 318.
The 318 A engine also evolved from the early 1953-55 V-8 and 1955 Super
Red Ram 270-cubic-inch "Hemi" engine. "Hemi" describes the
hemispherical-shaped combustion chamber in the heads. Because the intake
and exhaust valves are on opposite sides of the chamber, two rocker
shafts are required to operate them. This adds to the expense of the
engine, and Chrysler opted to drop the Hemi for normal street engines
and go with a polyspherical combustion chamber design on the then-new
318.
Chrysler, of course, went back to a Hemi head design in the early '60s
when horsepower ruled the world. My favorite engine of all time is the
426-cubic-inch Chrysler Hemi stuffed into lightweight Dodge and Plymouth
bodies "for racing purposes only." It will be the subject of an Engine
Report in the near future.
The 318's performance slotted between the Chevy 305- and 350 cubic-inch
engines. However, it tended to take more abuse from those who neglected
to change the oil and filter, or ran around without an air filter ("But
it makes more noise, dad!") so lots of these engines still remain with
us.
Problems
The 318 has been around for so long that all of the major problems have
long since been worked out. One area to watch, though, is in the valve
cover. Only two bolts, both in the center of the cover, hold it to the
head. If the bolts get wrenched down too tight, the cover will pucker
and oil leaks will appear. No more than 15 lb.-ft. of torque need be
applied to the bolts. Use new gaskets with some RTV on one side and
leaks will be avoided.
Watch which block you use for 1966-67 era cars. Lifters changed to
hydraulic in 1967 and the cams definitely are not interchangeable.
Boring a 318 past .040 in. oversize is a bad idea because of the danger
of striking water. There are so many millions of blocks floating around
that should your engine need a serious bore due to stuck or shattered
rings or a blown piston, you'd be far, far better off to start with
another block fresh from the wreckers.
Cylinder Heads
When machine facing the heads, don't go with a smooth finish. Too
slippery of a surface can actually allow the head gasket to move around
a bit. Both the block deck and head face should have a milled semi-rough
finish, not a ground finish. This helps to ensure against head gasket
leaks.
Valve Train and Cams
The "A" engine uses a shaft-supported rocker arm, fastened to the head
with five bolts. When rebuilding the engine, replace the shafts. I know,
the old ones look pretty good, but use them for pry bars and put new
shafts on the heads. This will help to ensure a quiet-running engine.
When replacing guides, aluminum-bronze guide installations (of the coil
variety) will provide excellent life all the way into the 100,000-mile
area. In all cases, surface finish of the valve stems is critical in
determining their overall life. The valve stems should be polished
smooth-the smoother the better. In addition, make sure there are no
nicks in the stem that can eat away the guide. This preparation will aid
a great deal in oil control and consumption.
Pistons and Rods
All "A" engines use the same length rod - 6.123-inch center-to-center of
the pin and crank journal bores. Many different rods are available for
the various-sized "A" engines, but the street 318 rod is part #2406785.
There is a P-part rod for hard usage, #P3690641, but it's only needed if
a lot of racing is contemplated; probably something that's not going to
happen too often if your 318 is in a '63 Dodge 880 fourdoor sedan.
There are so many different pistons available for the 318 that finding
the right one pretty much depends on the compression ratio you want to
run. Stick to 9:1 for best all-around use. Watch the ring grooves for
proper size. All rings should be 5/64-inch top and second groove, and
3/16-inch bottom oil groove.
Factory rings are fine for almost all applications. When the three-piece
oil ring assembly is installed on the piston, you must make sure that
the ends of the expanders are locked together properly. Check this
closely. if they are not locked, the oil ring won't function correctly.
During final assembly, the rings and piston skirts must be lubricated
thoroughly. Dunk the whole assembly in a can of oil just prior to
installing the ring compressor.
Crank
The 273, 318 and 340 cranks all have the same stroke and are
interchangeable on later engines, but not to earlier '66 and older. The
crank damper for the specific engine must be used, though. Avoid trying
to retrofit a newer crank from an "LA" engine into an "A" engine.
For a set of bullet-proof main bearings, use the TRW set MS-2714P. These
are fully grooved and have an extra-wide copper-faced thrust washer
surface.
Cranks with a fillet radius between the counterweights and the bearing
journals must be checked to ensure there's no interference with the
bearing edge. The bearing can be relieved by careful use of a bearing
knife. This isn't particularly hard to do, but I'd practice on an old
bearing before hacking upon a new set.
There has been some trouble with outer ring slippage on crankshaft
dampers on engines that get turned up a bit.
Should your 318 find itself entering a few speed contests, it would
benefit from having a line scribed across the face of the damper so that
any slippage can be detected. if the outer ring rotates, the crank will
go out of balance with the usual results-vibration and possible crank
and bearing destruction. In general, follow the guidelines, buy a
factory manual, take your time, and you'll be rewarded with an engine
that will still he running when Social Security is but a fond memory.
###
GENERAL SPECIFICATIONS
Bore x Stroke: 3.91 in. x 3.31 in.
Displacement: 318 cubic inches
Compression ratio: 9.00:1
Carburetor: 2-barrel
Maximum brake horsepower: 230 @ 4400 rpm
Maximum torque: 340 lb.-ft. @ 2400 rpm
Normal oil pressure: 45-65 psi
Tune-up specifications
Spark plugs: Champion N14Y (3/4-in. reach); J14Y (Canadian with 3/8-in.
reach) Gap: .035 in.
Timing mark: on crankshaft damper
Engine idle speed (with A/C running):
Automatic-500 rpm (in Drive)
Manual-500 rpm
Cylinder head bolt torque:
95 lb.-ft. (composition gasket)
85 lb.-ft. (steel gasket)
Compression pressure: 140 psi.
Fuel pump pressure: 5-7 psi
Valve operating clearances:
intake, .013 in. hot
exhaust, .021 in. hot
Valve spring pressure: 145 lbs. @ 15/16 in.
Valve seat angle: intake & exhaust seat - 45 degrees face - 45 degrees
Piston & ring specifications
All pistons removed from top
Ring gap:
Compression-.010 in.
Oil-.01 5 in.
Piston clearance at top of skirt: .0005-.0015 in.
Wristpin diameter: .9842 in.
Distributor specifications
Part number: 2444258 (1966 only), number located on distributor housing
Breaker gap: .017 in.
Dwell angle: 28-32 degrees
Centrifugal advance:
Starts-1 degree @ 480 rpm
Full advance-12 degrees @ 2300 rpm
Vacuum advance:
Starts @ 5.0-8.0 in. of vacuum
Total vacuum advance-11 degrees@ 12 in. of vacuum
If advance is checked on car, double the rpm and degree advance to get
crankshaft figures.
Firing order: 1-8-4-3-6-5-7-2
Engine number is located at the left front of the block below the
cylinder head.
Bearing specifications
Connecting rod bearings:
Journal diameter: 2.124-2.125 in.
Bearing clearance: .0005-.0015 in.
Rod bolt tension: 45 lb.-ft.
Main bearings:
Journal diameter:
Front: 2,4995-2.5005 in.
Clearance: .0005-.0015 in.
Main bolt tension: 85 lb.-ft.
Note: vibration damper must be 200 lb.-in.
INTERCHANGE GUIDE
Complete Engines
Up to the flywheel or converter all "A" 318-cubic-inch engines
interchange.
Note: Standard transmission engines fit automatics, but not visa-versa
without machining for a pilot bushing.
Engine Blocks
Dodge/Plymouth 1962-66 interchange.
Dodge/Plymouth 1959-61 will interchange.
Early engine blocks cross over on an individual basis. For instance,
some 1958 engines did not have a hole in the block for the 1957 oil
filler pipe.
Crank
Standard trans cranks fit the automatics, but not the other way around
unless a pilot bushing hole is cut. Dodge/Plymouth 1962-65 will
interchange.
Dodge/Plymouth 1959-61 will interchange. Earlier will cross only on a
one-forone basis.
Exhaust Manifolds
Right and left manifolds will interchange on all 318 A engines.
Some with air conditioning or power steering will have to be swapped on
a onefor-one basis.
Heads
Heads will interchange the same as other parts by year, but air
conditioning, accessory mounts and air suspension will make for
different mounting holes. Check them carefully.
Parts
Kanter Auto Products
76 Monroe St.
Boonton, NJ 07005
210/334-9575
Pro Antique Auto Parts
50 King Spring Road
Windsor Locks, CT 06096
860/623-8274
1929-64 Mopar parts
Year One
P.O. Box 129
Tucker, GA 30085
800/950-9503
www.yearone.com
Clubs
Chrysler Product Owners Club
1505 Wheaton Lane
Silver Spring, MD 20902
National Chrysler Products Club
5516 Silver Greek Drive
Mechanicsburg, PA 17055
WPC (Walter P. Chrysler Club)
P.O. Box 3504
Kalamazoo, MI 49003-3504
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