davey and all,
Before starting the engine, get some oil pressure. Remove the spark plugs and crank the engine over for thirty second bursts until you see pressure on the gauge. Do this any time the engine or the oil system has been apart.
It's too cold for 20W50, new engine or not. Put some 10W40 in the engine. The brand doesn't matter now. Don't idle it for too long, since the camshaft is already as broken in as it's going to get. However, don't go for much of a drive either. The first thing you want to do is get the engine up to normal operating temperature, and then shut it off. This would be the same procedure I'd use for a total rebuild as well, except that I always run the engine for at least twenty minutes at around 1800RPM. Having gotten to normal temperature and shut down, I next do the hardest part. Walk away from the thing and leave it over night. This is to allow it to come slowly down to ambient temperature.
We want the engine at ambient temperature so that everything is normalized for the cylinder head retorque. Loosen, and then torque, each head bolt/nut to specified torque in the order shown in the manual. You don't have to loosen very far. An eighth of a turn is quite sufficient. Use a click-stop torque wrench which is either relatively new or has been calibrated within memory. When you swing a torque wrench you want the "click" or the specified torque to be reached dynamically. That is, while the wrench is moving. Don't be shy. If you stop before the click occurs, you'll find that when you resume motion the click will take place before the fastener even moves. That is static or overcoming torque. It is a false reading. If this happens, start over on that bolt/nut. Plan the swing of your wrench so that you'll have plenty of space (arc) for the event to happen while in motion. Does it sound like I think this step is really important? It should.
Now check all the fluids, get the idle reasonable, and go for that ride. Don't expect miracles. The engine will probably need different tuning than it had before the rebuild. Make it a short ride, stopping here and there to check for leaks, say ten minutes. It's time for the first oil and filter change. Use the same weight oil you used to do the initial startup. Add some more camshaft break-in lube to the crankcase. I like the Kent stuff. It has all the goodies you need to keep the camshaft happy while running it in. This is the time to get all the tuning details right. Recheck the ignition timing and advance and adjust the idle mixture.
If this has been a total rebuild it's time to "seat" the rings. Not everybody believes this step is neccessary or that it actually accomplishes anything. I can't tell for sure, but I do it. It won't hurt anything, anyway. Get the car going at about 35 MPH in top gear and accellerate to 55 with a fairly heavy, but sensitive foot. Don't baby it, but don't lug it so hard it's bucking and chattering,either. Now slow down to 35 again, cruise for a few hundered feet and repeat the procedure. Do this four or five times. Then drive normally for several miles and enjoy the fruits of your labors. Your next oil change is due in fifty or sixty miles.
With these engines, I use 10W 40 in the late fall and winter, then switch to 20W50 for the late spring thru summer. I prefer Castrol. I used to use Duckham's 15W50, but I can't find it any more. Kendall is another good brand. My policy is to always use an additive now to replace the ZDDP that has been taken away from us. Strangely enough, STP in the red can has plenty of it, and it's not all that expensive either. There are other additives coming on the market all the time. I know some folks are using diesel oil. This would be convenient for me. I have the stuff here in the shop since I have a diesel truck. My understanding is that the ZDDP in diesel oil has now also been reduced, though I don't really know how far, because new diesel trucks are comming out with catalytic converters. I think it's wise to use an additive even after breaking in your engine. I've taken apart a LOT of engines, and you just wouldn't believe some of the lifters and cam lobes I've seen. Anyhow, on with the running in.
For the first eight hundred miles or so, don't have too much fun (high revs) and don't use a steady speed on the highway. Vary things a bit to avoid cyclic vibration. That droning cyclic sound indicates vibrations which can disturb the proper seating of components. Don't be fanatic about it, to the point where your fellow motorists are cheesed off at you, just accellerate now and then, and back off once in a while.
Proper running in can really pay off in the form of extended engine life and improved performance, but you'll throw it all away if you don't maintain the engine well. Overheating, especially while the engine is in it's "formative years" will equal many many miles of normal service. So will running with too rich a mixture. This can wash fuel down the cylinder walls and cause premature "erasure" of the cross-hatch patern, an important feature for retaining lubrication of the piston rings. Finally, regular oil/filter changes, not just respecting miles, but also time, are an important ritual for longevity.
I'm sure I've left questions unanswered. Ask them. I wanted to be thorough, but when I started concieving all this, I began thinking of things that should be done during assembly, installation, etc... blah... I tend toward the neverending monologue anyway, so I thought I'd just hit the high points and wait for suggestions, comments, questions, complaints, brickbats, (just what the hell is a brickbat, anyway?) So bring "em on.
Bill
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon