| Engine Replacement, Part 6 -- Old Engine Disassembly |
From "Weekend Mechanic"
episode WKM-206 |
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Old Engine Disassembly With the old engine out of the vehicle, work gets underway on disassembly to salvage parts that will be used on the new engine. Important: Included below are the steps in this automotive procedure as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. There are also variations according to the type and brand of replacement engine and other replacement parts that you select. Always consult your vehicle's service manual when undertaking significant automotive repairs, and read and follow the manufacturer's directions and precautions that come with your new engine or replacement parts. Safety Alert: Always wear eye protection, and follow proper safety precautions, when working with power tools and when working beneath a vehicle. - For greater efficiency and clarity in the disassembly process, the old engine and new engine are placed side-by-side, oriented the same way (figure A) to make transfer of old parts onto the new engine easier.
- Examples of parts that may (if they are in good shape) be transferred directly from the old engine to the new one include various engine sensors. The first one removed is the coolant-temperature sensor (figure B) for the onboard computer system. This particular sensor is stripped, and will need to be replaced with a new one.
- Next, the oil-pressure sensor is removed, followed by the temperature-gauge sensor (figure C). Both of these sensors are in good shape, and can be installed on the new engine.
Tip: Don't use your power tools to remove sensors. They are delicate, and can damage easily. - Since the new engine can be adapted to fit several car models, there are a number of sensor ports and they are plugged. After checking the old engine and the service manual to identify the proper ports, the correct ports for this vehicle are opened using a ratchet (figure D).
- Apply sealant to the sensors that will be installed in coolant pathways (figure E), and also to the oil-pressure sensor. Avoid getting sealant on the sensor tip, as this will prevent the sensor from operating properly.
- Carefully install the sensors in their designated locations on the new engine.
- Tip: It's a good idea to take photos of the old engine for reference before you begin removing parts, and throughout the process. The photos serve as reference for proper transfer and installation of parts onto the new engine. Digital photography is ideal for this.
- Now the process of removing larger engine accessories from the old engine can get underway. Begin by unbolting and removing the a/c-compressor/alternator mounting bracket (figure F). Note the length of the bolts as you remove them. If they're not all the same length, make note of which bolt goes in which hole.
- Unbolt and remove the lower timing cover (figure G). If your cover is plastic, use caution to avoid cracking it during removal. If it cracks, it will need to be replaced.
- Next, remove the top motor mount from its mounting studs (figure H). Note that a piece of foam can probably be found inside the motor-mount assembly. The foam prevents debris from getting into timing belt area. If the foam is in good shape, retain it for installation on the new engine.
- Remove the studs from the old engine. This can be done by a process known as double-nutting. Install one nut onto the stud, then a second one. Tighten the two nuts against each other. The joined back-nut can now be used to safely turn the stud (figure I) to remove it from the engine block without damaging it.
- Once they're removed, apply sealant to the ends of the studs and install them onto the new engine (figure J).
- Next, unbolt and remove the water-pump and associated housing (figure K). Ours are held in place by four bolts.
- Remove the distributor next (figure L). The distributor is one of the last items that will be replaced on the car.
- Remove the thermostat housing and thermostat (figure M). The housing will be reused, but the thermostat itself will be replaced as routine maintenance.
- The dip-stick tube will need to be removed. This tube is thin and fragile. Spray some solvent onto it, and let it soak for a while before attempting to remove it.
- While the solvent is working, you can disconnect the coolant-pipe assembly (figure N). This part may be custom-designed for specific vehicles, so use caution to avoid damage when removing it. If it's damaged, a suitable replacement may be difficult to find.
- Unbolt and carefully remove the valve cover from the engine (figure O). Ours is installed with two different size bolts, so we are careful to note of where they are installed. The bolts are installed through a thin metal plate. Remove and retain the plate for use on the new engine.
- With the valve-cover off, remove the splash shield that's housed underneath it (figure P) to reveal the camshaft.
- Next, rotate the engine on the stand so that the intake manifold is oriented up (figure Q).
- Unbolt and remove the intake and exhaust manifold assembly. Once unbolted, the manifolds can be lifted off in one piece (figure R). Set these aside for cleaning and reuse.
- Now, rotate the engine further on the stand to access the oil pump, and carefully remove it (figure S).
Tip: The oil pump should not be reused, and engine-salvage companies don't want old ones. Remove the old oil pump and discard it. It will need to be replaced with a new one. - Now that the solvent has had time to work on the dip-stick tube, carefully remove it. In our case, the tube broke off during this process (figure T) so a replacement was required. A new one costs about $15.
- Since our project vehicle had a fuel-injected engine, it had a fuel-pump block-off plate installed in the location where a fuel-pump would be installed on a carbureted engine. This plate needs to be removed (figure U) and retained for re-use. Discard the associated gasket, and replace it with a new one when the part is transferred.
- This completes the removal of parts from the old engine. Now, using the hoist, the old engine can be removed from the stand, and the new engine can be placed upon it (figure V).
- The old engine is placed in the shipping container that the new engine came in. It will be shipped back to the engine manufacturer for use as a "core" to make another remanufactured engine.
- The removed parts are soaked overnight in solvent, and prepared for cleaning and installation on the new engine.
In the segment that follows, the removed and cleaned-up parts are transferred onto the new engine.
RESOURCES :
The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books
How Cars Work
Author: Tom Newton
ISBN: 0966862309
Publisher: Black Apple Press
Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896
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