Testing the engine when inspecting and LBC is usually limited by the amount
of time or the amount the prospective DPO allows you to dig in. I would
try to bring along the following tools, in order of importance:
Rags and towels
Spark plug wrench
Volt Ohmeter
Jack and jackstands
Compression Gauge
Squirt oil can.
Can of Carb cleaner
First, grill the owner. Ask every question you can think of. This will
serve two purposes. First, you will find out how knowledgeable he is.
Second, after you check over the car, comparing what he said to what you
find will help you to judge how truthful he has been.
With the engine cold, pull the spark plugs and look at them. Oil fouling
is bad. A lot of LBC's with worn carbs run rich at idle so don't be
surprised if the are covered with black soot but tar-like deposits are not
good. Check the exhaust outlet for oil deposits. If the car has brand new
plugs, look out.
Check for good maintenance. Look for oil in the dashpots. Look at the
engine oil. Smell the engine oil. If it smells ugly, it could be a sign
of blowby. If the oil is light brown-opaque (kind of like a chocolate
malt) it is getting antifreeze into the oil. This usually means a cracked
block. Check the antifreeze. If it is oily or brown colored, this could
be a sign of a cracked head or blown head gasket. Or it could be from Bars
Leak radiator goop. In either case it is a cause for alarm. Check for
originality and condition of parts. Be aware if the engine is too dirty or
too clean.
Raise the car. Look for oil leaks. Lots of oil out of the rear of older
LBC's including MGA's can be expensive.
With the car on the ground again, do a compression check. If low readings,
large differences between cylinders, or a long "pump up" time is noticed,
repeat after squirting oil in each hole. If oil helps, the rings are bad.
If not, its the valves. (I have not ever done a compressin check on a car
that I have bought but if you can, it is a good idea.)
Replace the sparkplugs. Unhook the power wire from the coil or, with older
cars, crank it over without turning it on. The engine should turn over
smoothly without skips or changes. If the engine "lopes" on the starter,
it probably has a bad valve. (not necessary if compression check was done)
Start the engine. Cold oil pressure varies from car to car. I believe
MGA's should be around 50 PSI. Notice if the choke and such work
correctly. Check the output of the generator. It should be around 13-15
volts. Under 12 volts means a bad generator or regulator.
Drive the car until it is warmed up (about 20 minutes). Notice how smooth
the Idle is. Check the idle mixture by lifting the slide. It will
probably be rich. Spray the carburator cleaner around the throttle shofts.
If the idle changes, they are worn.
Using the shop rags and EXTREME CAUTION, remove the radiator cap. Check
for bubbles in the antifreeze that would show a blown head gasket or
cracked head.
Remove the oil fill cap. If you get a solid stream of foul smelling,
slighly moist air coming out, the rings are bad. (not necessary if
compression check was done)
Shut the car off. Restart it. If it turns over slower than it did cold,
the bushings on the starter are shot.
Check the oil pressure again. If the pressure has dropped considerably,
the bearings are loose. If it is below around 10 PSI at idle, they are
very loose and should be replaced as soon as possible.
As always, this is my opinion, YMMV, yada yada yada
Regards
Bill Eastman
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