Pre-Lubricating a Rebuilt Engine

You’ve spent weeks lovingly rebuilding your Healey’s tired engine.

You’ve spared no expense in providing it with the best quality parts, each one hand-fitted with great precision. It’s finally installed in the chassis with everything hooked up, ready for it’s first start-up.

Panic seizes you now as you think of all that virgin metal spinning without the benefit of the engine’s lifeblood – oil. What if she won’t start right away and will require extended cranking? What if the oil pump won’t supply an adequate amount of oil quickly to those vulnerable bearings? You’ve been generous with the assembly lubricant but what if it doesn’t last?

There is a way to minimize the chance of damage, and that is to pre-lubricate the engine to fill all the oil galleries with oil. On a six-cylinder Healey, there is no way to spin the oil pump alone as it is driven off the camshaft. The answer lies in the use of a spin-on oil filter adapter, available from various sources.

Most spin-on adapters have a threaded male stub that extends out approximately one inch, onto which the filter screws. A second hole in the adapter allows access to the oil pump itself (pump output). The threaded port is the single point at which oil is fed to the entire engine and is the one we want to connect to.

Before you begin, remember that avoiding injury to man and machine is of paramount importance. A few basics and common sense can go a long way towards avoiding a disaster:

  • Disconnect the ignition coil so that the engine absolutely cannot start
  • Ideally, do not put any fuel in the tank. Otherwise, disconnect the fuel line to the carburetors, plug the open end of the hose and unhook the wire from the fuel pump.
  • Make sure you have a pressure regulator on your compressor or air line to limit the pressure to 10 psi, with a shut-off valve
  • Always, always, wear safety glasses

From your local parts store, purchase a length of (typically 3/4″ ID) heater hose and clamps. Slide one end of the hose onto the threaded stub and secure it with a hose clamp. Connect the other end to a pressure pot, for example, the kind that is used with a paint spray gun. Pour a quart of oil into the pot and hook it up to your compressed air source, which should be turned off at this time.

Now is also a convenient time to deal with that pesky oil pressure gauge on the dash. Connect a length of clear tubing (5/16″ ID) to the end of the solid line after disconnecting it from the back of the gauge and run the other end into an empty can or bottle.

Slowly apply air pressure to the pot and watch the clamps for signs of leakage. Increase pressure steadily to about 5 psi and watch the tubing coming off the oil gauge line. When it fills up with oil, release and turn off the air pressure and plumb the oil line into the gauge. Ensure that you still have the sealing washer on the gauge fitting.

Re-pressurize the pot, starting at 0 psi and continue pumping oil into the engine. Your gauge should now register some pressure. When oil flows out of all the rockers, you have put in enough oil to fill all the internal passages. Make sure your pot does not run out of oil as that may push air into the block, displacing the oil. Release and disconnect air pressure but don’t disconnect the oil hose as yet as some oil will flow back down and make a mess of your perfectly clean engine. After about five minutes, unhook the hose while having a can and rag handy to catch anything that flows out. Remember to thoroughly clean out your pressure pot or you may have a rude surprise the next time you use it to paint with.

You can now prime the oil pump if you haven’t already done so. Use a length of tubing that will fit into the other hole in the adapter and stuff it in as far as it will go. With a funnel, slowly pour some oil down into the oil pump. Keep a close eye as it will fill quickly and then abruptly reject the rest of the oil, which will, naturally, stream down the side of your engine.

Place a can under the filter adapter and crank the engine. Oil should pulse out of the pump, confirming good priming. Make sure your dipstick registers the proper oil level, install the oil filter, any covers and fittings, etc. and crank the engine. It will take a few seconds (10 -15, depending upon filter size) for the filter to fill with oil after which you should see pressure on the gauge.

If there’s pressure, connect ignition and fuel, cross your fingers and start her up!