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Engine Repair Auto Service Tech Tips
These Tech Tips are provided courtesy of autoclassroom.com, an online training resource for automotive instructors, students, and technicians.
The hose trick
Installing spark plugs can be made easier by using a rubber hose on the end of the spark plug. The hose can be a vacuum hose, a fuel line, or even an old spark plug wire end. The hose makes it easy to start the threads of the spark plug into the cylinder head. After starting the threads, continue to thread the spark plug for several turns. Using the hose eliminates the chance of cross-threading the plug. This is especially important when installing spark plugs in aluminum cylinder heads.
The foot powder spray trick
The source of an oil or other fluid leak is often difficult to determine. A quick and easy method that works is the following. First, clean the entire area. This can best be done by using a commercially available degreaser to spray the entire area. Let it soak to loosen all accumulated oil and greasy dirt. Clean off the degreaser with a water hose. Let the area dry. Start the engine, and using spray foot powder or some other aerosol powder product, spray the entire area. The leak will turn the white powder dark. The exact location of any leak can be quickly located.
A picture is worth a thousand words
Take pictures with a Polaroid camera or a video camera of the engine being serviced. These pictures will be worth their weight in gold when it comes time to reassemble or reinstall the engine. It is very difficult for anyone to remember the exact location of every bracket, wire, and hose. Referring back to the photos of the engine before work was started will help you restore the vehicle to like-new condition.
Use the proper disassembly procedure
When an engine is operated, it builds up internal stresses. Even cast iron parts such as cylinder heads can warp if the proper disassembly procedure is not followed. To disassemble any engine without causing harm, just remember these two important points:
Disassemble parts from an engine only after it has been allowed to sit for several hours. All engines should be disassembled when the engine is at room temperature.
Always loosen retaining bolts/nuts in the reverse order of assembly. Most vehicle manufacturers recommend tightening bolts from the center of the component such as a cylinder head toward the outside (ends). Therefore, to disassemble the engine, the outside (outer) bolts should be loosened first followed by bolts closer to the center.
Both of these steps will help reduce the possibility of warpage occurring when the parts are removed.
The wax trick
Before the engine block can be thoroughly cleaned, all oil gallery plugs must be removed. A popular trick of the trade involves heating the plug (not the surrounding metal) with an oxyacetylene torch. The heat tends to expand the plug and make it tighter in the block. Do not overheat. As the plug is cooling, touch the plug with paraffin wax (beeswax or candle wax may be used). The wax will be drawn down around the threads of the plug by capillary attraction as the plug cools and contracts. After being allowed to cool, the plug is easily removed. |
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