Pelican Parts Forums - what to check on used motor

47silver,

Yes, cylinder leak test first and note the spark plug condition.
An immediate second is to remove the valve covers and inspect the depth position of each cylinder head stud end inside the cylinder head (barrel, internal 10 mm hex) nuts.
They should all be the same with proper purchase depth for a hex wrench.
Test the head nut torque at about 2/3 spec (spec = 30-33 Nm, 40.7- 44.7 ft-lbs), 30 ft-lbs should suffice. If a nut turns easily, STOP.
Inspect the undersides of the cylinders at the crankcase to confirm ‘case-saver’ inserts in the crankcase.
Note the markings on the cylinders.

Post images of everything you see.

Check (measure, don’t adjust) the valve clearances.
You just want to confirm reasonable clearances, not adjust until after some (1000 mi?) driving.
If you find some ‘tight’, you must adjust them but they will probably be too ‘loose’ later.
This is a good opportunity to confirm proper cam timing.

Drain the crankcase oil via the drain plug (not loosening the sump plate). Save the oil in a clean container.
Remove sump plate and screen and carefully inspect around the perimeter and bottom for debris.

Hopefully the engine has an 11-blade fan and back-dated (or up-dated to 911SC) exhaust.

Unless the 5000-mi-old seals show signs of leaking, I would leave them undisturbed.

Are the high-voltage ignition components (cap rotor, wires, plug connectors) ‘fresh’? If unknown, replace all.

Don’t blow air through the fuel system.
Connect it to your clean fuel system in your car and circulate fresh, clean fuel through the system.
Check the nozzle spray patter into six glass containers (20-25 ml graduated cylinders work well).
Note that all six remain equal volume.
Look for fuel leaks – even the smallest ‘seep’ is unacceptable.
Remember – gasoline (and vapors) are the most dangerous substance you ever come in contact with (unless you build nuclear weapons).

Is your oil system (tank, lines, thermostat, cooler) clean?
If not sure, now is the time.

When you inspect the clutch disc from your current engine, note if there are any signs that the transmission input shaft seal is (or has been) leaking.
You don’t want to damage a new (or good) clutch disc with transmission oil.

Be sure to lube the pilot bearing and clean & lube the splines on the input shaft and the inside splines of the clutch disc. Test-fit the disc on the transmission shaft.
If you have the flywheel off, these six bolts are supposed to be ‘use once’. Many get re-used but ‘how many times?’

With the engine separated from the transmission, now is the time to ‘freshen’ the clutch linkage.
Be sure to inspect the ‘fork’ at the clutch release (TO) bearing for potential cracks.
Remember, you will need new new M10 Schnorr washers and possibly new CV joint bolts.

Clean everything.
On a ‘daily’, I’m inclined to cover everything underneath with Tectyl (Factory wax preservative).

When it is time to start the engine, crank for oil pressure with the plugs out, fuel & ignition disabled.
Make sure the fuel and ignition are in prime condition to start and run properly from first attempt.
You will want to treat the engine gently as it will need to ‘brake-in’ as if new.

Enjoy :cool:

Best,
Grady (CMU EE '68)