Cheap Tricks for engines

Use an old ignition wire to get to those har-to-reach plug holes. This way you avoid ruining the tread while using a wrench.
To avoid that the rubber or cork seals wander around and slide away while you try to fix that damn thing here's an easy trick. Strip off a few inches of an old cable. The inner wire consists of many thin copper wires. Use one of those thin (generally 0.1 mm2) strands to fix the seal to each hole. After fixing the whole thing you can either simply remove the wires by pulling on them or leave them in place as they are so thin.
To make checking oil levels easier put some fluorescenting paint around the end of the tubes. It will come very handy on those dimly lit service stations at night.
Use an big piece of cardboard to collect the various nuts and bolts. On some parts with a lot of differing bolts trace the outline of the piece on the cardboard and stick the bolts in the corresponding places. The water pumps on modern Land Rovers are a good example for practising this.
When taking your intake manifold and head off take some time to remove any casting traces and marks. Make a nice, smooth finish but do not try to enlarge the passages unless you know what you're doing. Simply removing the casting burrs allows for a much better air flow, giving a better filling with air. Don't think you will get a racer though, this modification can only be detected by a rolling road. Think about 2-3 horses max. And don't try to make a polished finish, this isn't good for air flow in most cases. At last, dont forget to clean the heads very thorougly.
Next time you have removed your fan paint the outside edges of the blades in a bright color. They are so sharp you will never forget them once you touch them running. It's a very cheap way to avoid nasty wounds.
If you have to remove the clutch pilot bearing which is always a good idea as it costs only a few bucks, you can get by without buying a special bearing puller if you fill the hole with grease. Than get a tube or bolt that matches the bore as close as possible. Tap now this in. The pressure of the grease will push the bearing out.
An easy way to check radiators for leaks is using an old bycicle tube. Cut it up and connect it between upper and lower inlets. Fill the radiator full with water than pump it it with a small hand pump. Don't use a compressor as it needs only a very small amount of air to get high pressures. Anything over 15 p.s.i. will damage the radiator