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| − | ==Introduction==
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| − | This page will give the buyer of an engine that's new to them a list of things that should be checked/confirmed to be within specs '''before''' using the engine. It is intended to be a general guide, not all these things will apply to all engines and the list might not be all-inclusive.
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| − | ==Let the buyer beware==
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| − | In almost every case of the casual sale of a used engine, the sale is considered to be on an "as-is" basis. So regardless of what might have been said or inferred about the engine condition or specs or what parts an engine may contain, it is the new owner's responsibility to check the entire engine over to be sure it's what it's supposed to be, or if it needs additional work or parts in order to be usable.
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| − | ==Checking engine's basic health==
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| − | First thing is to look at is all the fluids and the air filter to get an indication of how the engine was maintained.
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| − | Check the oil for water and the water for oil. Either can indicate a blown head gasket or cracked block.
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| − | Remove the breather and PCV to look for obvious signs of sludge. Check cooling system for rust and the radiator for clogged tubes or evidence of leaks that could have caused overheating.
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| − | Next, start the engine and warm it up. Remove one spark plug wire at a time using an insulated spark plug boot puller, noting any change in idle speed. If the idle speed drops, that cylinder was firing. Go through all the plugs and if there was a plug or plugs that the idle speed remained unchanged or nearly so, the next step is to see if it's a problem with the plug or wire. Remove the plug wire from the weak cylinder and swap it with a plug and wire from a cylinder that was working normally. If the weak cylinder is now OK, it was either the plug wire or the plug. Swap the wire from the weak cylinder with another good wire and see the results. If the miss followed the wire, the wire is bad, If not it's the plug.
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| − | If the miss did not follow the plug or wire, that cylinder or cylinders need to have a compression test performed on them. With the throttle propped wide open and the ignition disabled, crank the engine over letting the cylinder come up on compression three times. Note the reading. Next, squirt oil into the cylinder through the plug opening and test again. If the reading doesn't change, likely the valves aren't sealing. If the pressure comes up, there's a good chance it has worn or possibly broken rings.
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| − | ==Engine ID==
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| − | ===Casting numbers===
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| − | Using the casting numbers, casting dates, and suffix codes will all help identify the basic specs of an engine, regardless of the make. So if an engine needs to be verified as to displacement or other parameters, start with the casting numbers and any other visual cues that might be present.
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| − | ==Estimating stroke==
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| − | There can be cases where the casting numbers can tell you what you need to know. But in cases where the engine might have had the crank changed to a different stroke, the displacement won't be known. The most important thing about finding the displacement is the stroke because the bore will be very close to whatever the nominal bore size is for the casting number of the block in question.
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| − | Estimate the stroke of an assembled engine by simply inserting a piece of wire down the spark plug hole, rotate the engine by hand (taking all the spark plugs out helps here) to the bottom of the stroke, mark the wire, rotate to the top of the stroke, mark the wire again. The distance between the two marks is the approximate stroke. It won't be exact, but the diff between a ~3.5" and a 3-3/4" stroke can be seen if this is done carefully.
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| − | For a 350 SBC that has been stroked, another clue could be if the damper is scalloped. Many SBC 383 stroker engines are externally balanced. If it's internally balanced and has a 3-3/4" stroke, you can almost assuredly add 6" (or possibly longer) rods to the deal- they're used on internally balanced stroker builds quite often; a lot more than a 5.7" rod in any event.
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| − | If a flexplate/flywheel came with the engine, externally balanced 383 strokers will have a weight affixed to the plate or the counterweight drilled/cast into the flywheel.
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| − | Long shot, but if you can see well enough into the plug hole you might see the part number of the piston.
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| − | If this doesn't work for you, pull a head and/or the pan. I would strongly recommend doing this anyway in order to verify exactly what it is you have and to check a few things while you are there:
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| − | ==Some points to check:==
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| − | • '''[http://www.crankshaftcoalition.com/wiki/Valve_train_points_to_check HERE]''' is a list of valve train points to check, including the valve train geometry. This doesn't require any disassembly other than the valve cover to be removed and should be checked ''before'' tearing the engine down.
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| − | • Condition of the spark plugs (oil consumption, correct heat range and air/fuel ratio)
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| − | • Timing set phasing (cam advanced or retarded) and alignment
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| − | • Piston deck height (important for calculating the compression ratio and for setting the correct quench distance)
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| − | • Cam specs/cam part number from the end of the cam
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| − | • Condition of the lifters and cam lobes
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| − | • Bearing condition and oil clearances
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| − | • Rod bearing clearance at the crank fillet
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| − | • Crank end play
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| − | • Oil pick up distance to the bottom of the pan
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| − | • Attachment of the pick up to the oil pump
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| − | • Cam to rod and rod/crank to block clearances, if a stroker
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| − | • Ring end gap
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| − | • Piston to bore clearance
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| − | • Crosshatch pattern in the cylinders, general bore condition
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| − | • Wear patterns on the pistons
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| − | {{youcanedit}}
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| − | [[Category:Engine]]
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