Inspection of used engine

[jblair630]

Now that I am on the hunt for a used engine and I have my checklist of things to look for, a couple of questions come to mind...

1. Say I have found a shortblock/longblock/turnkey that was in good running condition and passed my initial inspection. I have just paid $$ for it but have yet to put it in the bus. What are the advantages or disadvantages of doing a complete teardown, cleaning and reassembly? Is it worth it to have a clean engine (inside and out) and know the condition of the inner workings or is it tempting fate to disturb the karma (mating surfaces, seals, etc) of a known runner?

2. After the engine is installed should I run it through a break-in as if it were a fresh rebuild?

3. Should I have the engine blessed by my local priest/medicine man/guru/high priestess to make certain that there's no hidden gremlins? (I need to exorcise a few of my own demons because right now they can't even do a couple of sit-ups)

Thanks

Jeffrey

[NWbuspilot]

If you need the engine put in in a hurry, make sure you are getting adequate compression, and pull the valve covers to get an idea of the valve condition. Having a clean engine is a great thing; if you spring an oil leak it makes it infinitely easier to find the source.

So I guess my advice would be this: Make sure it runs, has good compression and the valves look good. Clean it up really well. Run it for a day or two and see if you have any serious oil leaks, maybe even pull it out again after those few days and make sure the main seal isn't puking on the clutch. If you have bad leaks then replace the offending seal, which may involve cracking open the case.

[Amskeptic]

1. Is it worth it to have a clean engine (inside and out) and know the condition of the inner workings or is it tempting fate to disturb the karma (mating surfaces, seals, etc) of a known runner?

2. After the engine is installed should I run it through a break-in as if it were a fresh rebuild?

3. Should I have the engine blessed by my local priest/medicine man/guru/high priestess to make certain that there's no hidden gremlins? (I need to exorcise a few of my own demons because right now they can't even do a couple of sit-ups)

1. A used engine still in the vehicle is your best bet. Then you can check the dipstick for a nice light honey to darkish brown oil at the correct mark, pull the valve covers and look for tell-tale too hot black deposits in the rocker arm area vs the more desireable light brown, adjust its valves with an eye out for any tight ones, start it and listen for knocks and rattles at a floating high rpm, warm it up and see how it idles, do a drop the idle speed test with your clutch pedal, in 1st gear, to see if the oil light jumps on as you reduce the idle rpms, shut it down, push-pull the crankshaft pulley with verve to see if there is a longitudinal thunk (bad sign, too much endplay), look around for nasty oil leaks (literally leaky enough to rinse the crud off the engine) versus old chronic leaks (where there is maybe damp build-up of dirt but no clean wash of outer dirt build up), perform a compression test to see if all figures are within 20% of each other, and maybe it will run with such a steady beat that you decide to transfer the entire thing over instead of just the long block or short block. Last check would be to drop the strainer plate and look for any evidence of any metallic particles in the deposit at the bottom of the plate. If all is clean, a teardown would not be warranted. You may need to supply fuel in a can with a gravity-fed hose to the carburetor and a charged battery.

2. If it passes thunk test, oil/strainer cleanliness test, and compression test, just tune it up with fresh points and plugs, maybe new wires, then drive it.

3. You can ascertain the health of the engine with your own senses and compression test results. The end-play test can be easily enough calibrated with your hands. You know what .006" feels like at the rockers. Your crankshaft pulley must not exceed the same amount of movement. First have your able assistant push on the clutch pedal while you turn the engine either direction a little bit with a wrench on the generator pulley. Release clutch pedal and push the pulley hard towards the front of the car. Listen and feel for a thunk. A light click is vastly preferred. Repeat test until your intuition feels comfortable. With a used engine, power and driveability will tell you much. If Phred can pull up to 65 on the highway in decent time, the combustion related health of the engine is pretty good. If the engine can be slowed down and the oil light stays off, your oil pressure is good which tells you all the bearings are probably pretty decent (particularly with no knocking sounds when you do the rev test).
If ther engine is out of the vehicle, it can be started with some rube goldberg efforts. Some yards have a bell housing starter rig to start the engine out of the vehicle. You need to run a wire to the coil #15 from the starter terminal, be certain you can pull the wire off the coil easily to shurt the engine down, and you will need a fuel supply that you can rely upon to not embarrass you by catching everything on fire.

A clean well-lubricated not too knocky engine with decent compression, driven sensibly, will give you many miles even if it is unknown.
Colin