GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 466
wear. Worn piston rings, scored or wo
rn cylinder bores, blown head gaskets,
sticking or burnt valves, and worn valve seats are all possible culprits. A check
of each cylinder's compression will help locate the problem.
A screw-in type compression gauge is more accurate than the type you simply
hold against the spark plug hole. Although it takes slightly longer to use, it's
worth the effort to obtain a more accurate reading.
1. Make sure that the proper amount and viscosity of engine oil is in the
crankcase, then ensure the battery is fully charged.
2. Warm-up the engine to normal operat ing temperature, then shut the
engine OFF.
3. Disable the ignition system.
4. Label and disconnect all of the spark plug wires from the plugs.
5. Thoroughly clean the cylinder h ead area around the spark plug ports,
then remove the spark plugs.
6. Set the throttle plate to the fully open (wide-open throttle) position. You
can block the accelerator linkage open for this, or you can have an
assistant fully depress the accelerator pedal.
Fig. 1: A screw-in type compression gauge is more accurate and easier to use
without an assistant
7. Install a screw-in type compression gauge into the No. 1 spark plug hole
until the fitting is snug.
WARNING - Be careful not to crossthread the spark plug hole.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 467
8. According to the tool manufacture
r's instructions, connect a remote
starting switch to the starting circuit.
9. With the ignition switch in the OFF position, use the remote starting
switch to crank the engine through at least five compression strokes
(approximately 5 seconds of cranking) and record the highest reading on
the gauge.
10. Repeat the test on each cylinder, cranking the engine approximately the
same number of compression stroke s and/or time as the first.
11. Compare the highest readi ngs from each cylinder to that of the others.
The indicated compression pre ssures are considered within
specifications if the lo west reading cylinder is within 75 percent of the
pressure recorded for the highest readi ng cylinder. For example, if your
highest reading cylinder pressure was 150 psi (1034 kPa), then 75
percent of that would be 113 psi (779 kPa). So the lowest reading
cylinder should be no less than 113 psi (779 kPa).
12. If a cylinder exhibits an unusually low compression reading, pour a
tablespoon of clean engine oil into the cylinder through the spark plug
hole and repeat the compression tes t. If the compression rises after
adding oil, it means that the cylinder's piston rings and/or cylinder bore
are damaged or worn. If the pressure re mains low, the valves may not be
seating properly (a valve job is needed), or the head gasket may be
blown near that cylinder. If compressi on in any two adjacent cylinders is
low, and if the addition of oil doesn' t help raise compression, there is
leakage past the head gasket. Oil and coolant in the combustion
chamber, combined with blue or const ant white smoke from the tail pipe,
are symptoms of this pr oblem. However, don't be alarmed by the normal
white smoke emitted from the tail pipe during engine warm-up or from
cold weather driving. There may be evidence of water droplets on the
engine dipstick and/or oil droplets in the cooling system if a head gasket
is blown.
OIL PRESSURE TEST
Check for proper oil pressu re at the sending unit passage with an externally
mounted mechanical oil pressure gauge (a s opposed to relying on a factory
installed dash-mounted gauge). A tachom eter may also be needed, as some
specifications may require running the engine at a specific rpm.
1. With the engine cold, locate and remo ve the oil pressure sending unit.
2. Following the manufacturer's inst ructions, connect a mechanical oil
pressure gauge and, if necessary, a tachometer to the engine.
3. Start the engine and allow it to idle.
4. Check the oil pressure reading when cold and record the number. You
may need to run the engine at a specified rpm, so check the
specifications chart located earlier in this section.
5. Run the engine until normal operati ng temperature is reached (upper
radiator hose will feel warm).
6. Check the oil pressure reading agai n with the engine hot and record the
number. Turn the engine OFF.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 468
7. Compare your hot oil pressure reading
to that given in the chart. If the
reading is low, check the cold pressu re reading against the chart. If the
cold pressure is well above the spec ification, and the hot reading was
lower than the specificat ion, you may have the wr ong viscosity oil in the
engine. Change the oil, making sure to use the proper grade and
quantity, then repeat the test.
Low oil pressure readings could be attributed to internal component wear, pump
related problems, a low oil leve l, or oil viscosity that is too low. High oil pressure
readings could be caused by an overfilled crankcase, too high of an oil viscosity
or a faulty pressure relief valve.
BUY OR REBUILD?
Now that you have determined that your engine is worn out, you must make
some decisions. The question of whether or not an engine is worth rebuilding is
largely a subjective matter and one of per sonal worth. Is the engine a popular
one, or is it an obsolete model? Are parts available? Will it get acceptable gas
mileage once it is rebuilt? Is the car it's being put into worth keeping? Would it
be less expensive to buy a new engine, have your engine rebuilt by a pro,
rebuild it yourself or buy a used engine from a salvage yard? Or would it be
simpler and less expensive to buy another car? If you have considered all these
matters and more, and have still decided to r ebuild the engine, then it is time to
decide how you will rebuild it.
The editors of this information feel that most engine machining should be
performed by a professional machine shop. Don't think of it as wasting money,
rather, as an assurance that the job has been done right the first time. There
are many expensive and spec ialized tools required to perform such tasks as
boring and honing an engine block or having a valve job done on a cylinder
head. Even inspecting the parts requires expensive micrometers and gauges to
properly measure wear and clearances. Al so, a machine shop can deliver to
you clean, and ready to assemble parts, saving you time and aggravation. Your
maximum savings will come from perf orming the removal, disassembly,
assembly and installation of the engine and purchasing or renting only the tools
required to perform the above tasks. Depending on the particular
circumstances, you may save 40 to 60 perc ent of the cost doing these yourself.
A complete rebuild or overhaul of an engine involves replacing all of the moving
parts (pistons, rods, crankshaft, camsha ft, etc.) with new ones and machining
the non-moving wearing surfaces of t he block and heads. Unfortunately, this
may not be cost effective. For instanc e, your crankshaft may have been
damaged or worn, but it can be machined undersize for a minimal fee.
So, as you can see, you can replace ev erything inside the engine, but, it is
wiser to replace only those parts whic h are really needed, and, if possible,
repair the more expensive ones. Later in this section, we will break the engine
down into its two main components: t he cylinder head and the engine block. We
will discuss each component, and the re commended parts to replace during a
rebuild on each.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 469
ENGINE OVERHAUL TIPS
Most engine overhaul procedures are fair
ly standard. In addition to specific
parts replacement procedures and specifications for your individual engine, this
section is also a guide to acceptabl e rebuilding procedures. Examples of
standard rebuilding practice are given and should be used along with specific
details concerning your particular engine.
Competent and accurate machine sh op services will ensure maximum
performance, reliability and engin e life. In most instances it is more profitable for
the do-it-yourself mechanic to remove, clean and inspect the component, buy
the necessary parts and deliver these to a shop for actual machine work.
Much of the assembly work (crankshaft, bearings, piston rods, and other
components) is well within the scope of t he do-it-yourself mechanic's tools and
abilities. You will have to decide for your self the depth of involvement you desire
in an engine repair or rebuild.
TOOLS
The tools required for an engine overhaul or parts replacement will depend on
the depth of your involvement. With a few exceptions, they will be the tools
found in a mechanic's tool kit (see Gener al Information & Maintenance in this
repair guide). More in-depth work will requ ire some or all of the following:
• A dial indicator (reading in thousandths) mounted on a universal base
• Micrometers and telescope gauges
• Jaw and screw-type pullers
• Scraper
• Valve spring compressor
• Ring groove cleaner
• Piston ring expander and compressor
• Ridge reamer
• Cylinder hone or glaze breaker
• Plastigage®
• Engine stand
The use of most of these tools is illustra ted in this section. Many can be rented
for a one-time use from a local parts jobber or tool supply house specializing in
automotive work.
Occasionally, the use of special tools is called for. See the information on
Special Tools and the Safety Notice in General Information & Maintenance
before substituting another tool.
OVERHAUL TIPS
Aluminum has become extr emely popular for use in engines, due to its low
weight. Observe the follo wing precautions when handl ing aluminum parts:
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 470
•
Never hot tank aluminum parts (the c austic hot tank solution will eat the
aluminum.
• Remove all aluminum parts (identif ication tag, etc.) from engine parts
prior to the tanking.
• Always coat threads lightly with engine oil or anti-seize compounds
before installation, to prevent seizure.
• Never overtighten bolts or spark plugs especially in aluminum threads.
When assembling the engine, any parts that will be exposed to frictional contact
must be prelubed to provide lubricatio n at initial start-up. Any product
specifically formulated for this purpos e can be used, but engine oil is not
recommended as a prelube in most cases.
When semi-permanent (locked, but removabl e) installation of bolts or nuts is
desired, threads should be cleaned and coat ed with Loctite® or another similar,
commercial non-hardening sealant.
CLEANING
Before the engine and its components ar e inspected, they must be thoroughly
cleaned. You will need to remove any eng ine varnish, oil sludge and/or carbon
deposits from all of the com ponents to insure an accurate inspection. A crack in
the engine block or cylinder head can eas ily become overlooked if hidden by a
layer of sludge or carbon.
Fig. 1: Use a gasket scraper to remove t he old gasket material from the mating
surfaces
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 471
Most of the cleaning process can
be carried out with common hand tools and
readily available solvents or soluti ons. Carbon deposits can be chipped away
using a hammer and a hard wooden chisel. Old gasket material and varnish or
sludge can usually be re moved using a scraper and/ or cleaning solvent.
Extremely stubborn deposits may require the use of a power drill with a wire
brush. If using a wire brush, use extrem e care around any critical machined
surfaces (such as the gasket surfaces, bearing saddles, cylinder bores, etc.).
Use of a wire brush is NOT RECO MMENDED on any aluminum components.
Always follow any safety recommendations given by the manufacturer of the
tool and/or solvent. You s hould always wear eye prot ection during any cleaning
process involving scraping, chipping or spraying of solvents.
An alternative to the mess and hassle of cl eaning the parts yourself is to drop
them off at a local garage or machine shop. They will, more than likely, have the
necessary equipment to properly clean all of the parts for a nominal fee.
CAUTION - Always wear eye protection duri ng any cleaning process involving
scraping, chipping or spraying of solvents.
Fig. 2: Use a ring expander tool to remove the piston rings
Remove any oil galley plugs, freeze pl ugs and/or pressed-in bearings and
carefully wash and degrease all of the engine components including the
fasteners and bolts. Small par ts such as the valves, springs, etc., should be
placed in a metal basket and allowed to soak. Use pipe cleaner type brushes,
and clean all passageways in the co mponents. Use a ring expander and
remove the rings from the pistons. Cl ean the piston ring grooves with a special
tool or a piece of broken ri ng. Scrape the carbon off of the top of the piston. You
should never use a wire brush on the pist ons. After preparing all of the piston
assemblies in this manner, wash and degrease them again.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 476
Before attempting to repair a threaded
hole, remove any snapped, broken or
damaged bolts or studs. Penetrating oil ca n be used to free frozen threads. The
offending item can usually be removed with locking pliers or using a screw/stud
extractor. After the hole is clear, the thread can be repaired, as shown in the
series of accompanying illustrations and in the kit manufacturer's instructions.
ENGINE PREPARATION
To properly rebuild an engine, you must fi rst remove it from the vehicle, then
disassemble and diagnose it. Ideally you should place your engine on an engine
stand. This affords you the best access to the engine components. Follow the
manufacturer's directions for using the stand with your particular engine.
Remove the flywheel or fl explate before installing the engine to the stand.
Now that you have the engine on a stand, and assuming that you have drained
the oil and coolant from the engine, it's ti me to strip it of all but the necessary
components. Before you start disassembli ng the engine, you may want to take
a moment to draw some pictures, or fabr icate some labels or containers to mark
the locations of various components and the bolts and/or studs which fasten
them. Modern day engines use a lot of littl e brackets and clips which hold wiring
harnesses and such, and these holders are often mounted on studs and/or bolts
that can be easily mixed up. The manufacturer spent a lot of time and money
designing your vehicle, and they wouldn't have wasted any of it by haphazardly
placing brackets, clips or fasteners on t he vehicle. If it's present when you
disassemble it, put it back when you asse mble, you will regret not remembering
that little bracket which holds a wire har ness out of the path of a rotating part.
You should begin by unbolting any accessories still attached to the engine, such
as the water pump, power steering pump, alternator, etc. Then, unfasten any
manifolds (intake or exhaust) which were not removed during the engine
removal procedure. Finally, remove any covers remaining on the engine such
as the rocker arm, front or timing cove r and oil pan. Some front covers may
require the vibration dam per and/or crank pulley to be removed beforehand.
The idea is to reduce the engine to the bar e necessities (cylinder head(s), valve
train, engine block, crankshaft, pistons and connecting rods), plus any other 'in
block' components such as oil pumps, balance shafts and auxiliary shafts.
Finally, remove the cylinder head(s) from the engine block and carefully place
on a bench. Disassembly instructions fo r each component follow later in this
section.
CYLINDER HEAD
There are two basic types of cylinder heads used on today’s automobiles:
the Overhead Valve (OHV) and the Over head Camshaft (OHC). The latter can
also be broken down into two subgr oups: the Single Overhead Camshaft
(SOHC) and the Dual Overhead Camshaft (DO HC). Generally, if there is only a
single camshaft on a head, it is just referred to as an OHC head. Also, an
engine with a OHV cylinder head is also known as a pushrod engine.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 477
Most cylinder heads these days are made of
an aluminum alloy due to its light
weight, durability and heat transfer qualit ies. However, cast iron was the
material of choice in the past, and is st ill used on many vehicles today. Whether
made from aluminum or iron, all cylinder heads hav e valves and seats. Some
use two valves per cylinder, while the more hi-tech engines will utilize a multi-
valve configuration using 3, 4 and
even 5 valves per cylinder. When the va lve contacts the seat, it does so on
precision machined surfaces, which seal s the combustion chamber. All cylinder
heads have a valve guide for each valve. The guide centers the valve to the
seat and allows it to move up and down within it. The clearance between the
valve and guide can be critical. Too much clearance and the engine may
consume oil, lose vacuum and/or damage the seat. Too little, and the valve can
stick in the guide causing t he engine to run poorly if at all, and possibly causing
severe damage. The last component all cylinder heads have are valve springs.
The spring holds the valve against its s eat. It also returns the valve to this
position when the valve has been opened by the valve train or camshaft. The
spring is fastened to the valve by a retainer and valve locks (sometime\
s called
keepers). Aluminum heads will also have a valve spring shim to keep the spring
from wearing away the aluminum.
An ideal method of rebuilding the cylin der head would involve replacing all of
the valves, guides, seats, springs, et c. with new ones. However, depending on
how the engine was maintained, often this is not necessary. A major cause of
valve, guide and seat wear is an improperly tuned engine. An engine that is
running too rich, will often wash the lubric ating oil out of the guide with gasoline,
causing it to wear rapidly. Conversely, an engine which is running too lean will
place higher combustion temperatures on the valves and seats allowing them to
wear or even burn. Springs fall victim to the driving habits of the individual. A
driver who often runs the engine rpm to the redline will wear out or break the
springs faster then one that stays well below it. Unfortunately, mileage takes it
toll on all of the parts. G enerally, the valves, guides, springs and seats in a
cylinder head can be machined and re-used, saving you money. However, if a
valve is burnt, it may be wise to replace all of the valves, since they were all
operating in the same environment. The same goes for any other component\
on
the cylinder head. Think of it as an insurance policy against future problems
related to that component.
Unfortunately, the only way to find out wh ich components need replacing, is to
disassemble and carefully check each piece. After the cylinder head(s) are
disassembled, thoroughly clean all of the components.
DISASSEMBLY
Before disassembling the cylinder head, you may want to fabricate some
containers to hold the various parts, as some of them can be quite small (such
as keepers) and easily lost. Also keeping yourself and the components
organized will aid in assembly and reduce confusion. Where possible, try to
maintain a components original location; th is is especially important if there is
not going to be any machine work performed on the components.