How To Restore A Car Engine

January 7th, 2020

Restoring a car engine is very rewarding but not for the faint of heart. Restoration requires a lot of time, planning, and attention to detail. You can avoid costly mistakes and wasted time by being organized and getting the proper tools for the job.

The steps to any engine rebuild may vary according to the make and model of your vehicle. Be sure to use your engine manual when in doubt. Here are the basic steps to restoring an engine.

1. Prepare Your Car And Work Space

It is best to set up your work space before you dig into the engine. Your garage should be clean, well-lit, and secure. Access to basic hand tools and engine restoration tools (such as torque wrenches and engine hoists) is vital. Organize your tools and workspace so that tools are easy to find when you need them. Use plastic bags, permanent markers, and masking tape for storing and labeling engine parts.

Find a factory shop manual for the make and model vehicle you are restoring. A factory shop manual will spare you a lot of frustration and time wasted guessing. Your manual should explain in detail how to remove the engine properly, so read the manual thoroughly.

Find a good machine shop that can bore or fix machine components if needed. Find your replacement parts. Then get to work. 

Take the time to clean your engine before you begin removing parts. Cleaning the engine makes removing parts and inspecting for damage easier and cleaner. Remove the hood of your vehicle to give you as much space as possible. When removing the hood, disconnect any electrical connections for signal lights, fog lights, under hood lights, or headlamps. Mark and store the hinge bolts. 

If you have a smartphone, take pictures of your vehicle's parts in place before restoration begins. These pictures will be extremely helpful when putting the engine back together. 

2. Drain Fluids

Before you proceed, use jack stands to raise the front of your car. Using separate pans, drain the engine coolant and oil from the car. You must drain and store oil and coolant separately for proper disposal or recycling. 

3. Get Engine Ready For Extraction

Before beginning, disconnect the ground cable on the battery. As you remove parts, take pictures and put them into carefully labeled bags. You may need to cut rubber hoses, but try not to break any metal clamps you encounter as they are hard to replace. 

Begin by removing plastic covers, air intake tubes and filter housings from the engine. Take out the radiator so it isn't damaged during the engine removal. Disconnect heater hoses, the starter, battery, connectors, and any harnesses. When finished, use a flashlight to check the engine for any missed hoses or connectors and remove them. (By the way, if you need to replace any hoses, start here.)

If your model engine requires it, remove your exhaust manifolds and the starter. Take out the air compressor and its associated belts. The AC lines for the compressor do not need to be removed. If you are planning on leaving the transmission in your vehicle, place extra jack stands under it for extra support before disconnecting the engine. Place the bolts and other hardware in carefully labeled bags. 

engine extraction

Image via Flickr by docmonstereyes

4. Remove Engine And Get It On A Stand

After removing as many parts as possible, move the engine hoist into place over the engine and connect the hoist chains. Be sure to use high-strength bolts capable of supporting the engine weight and make sure they are securely attached. Before lifting the engine out of the vehicle, disconnect it from the motor mounts. Make sure there are no hoses or parts still attached before moving the engine to your engine stand. This step usually requires an extra set of hands. Keep the engine level and steady as you move it to prevent damage to the engine vehicle. Mount your engine onto an engine stand using strong, high-grade hardware.

5. Inspect The Engine

It may seem unnecessary, but it is a good idea to double-check the engine ID and casting number before proceeding. It isn't uncommon to have a different engine in your vehicle than expected, especially if you are working on an older car. All components on your engine should be closely inspected. Use a reliable parts store such as Suburban Auto Parts to replace any damaged or broken parts.

6. Take Apart The Rest Of The Engine

Position pans under the engine stand for catching leftover coolant or oil. Keep inspecting parts for damage as you handle them. Label all reusable parts for easy rebuilding later. 

If you haven't already, remove the exhaust manifold. Exhaust manifold bolts can get very corroded over time, so be prepared to use special lubricants and heat to remove them. Remove the oil pan, rocker arms, valve covers, and pushrods. Be careful not to bend or damage the lifter rods. 

Remove the head bolts from the cylinder and then take off the timing chain.

Remove the rod caps and then the piston and rod assembly. When removing connecting rod studs, use covers on them to protect the walls of the cylinders from scratches. Be sure to keep each rod cap matched to their hardware to ensure a good fit when they are placed back in the engine. Remove the pistons carefully from the cylinders to protect the walls from damage. If your cylinders are very worn, you may need to have the engine bored at a machine shop and use oversized pistons in your restoration.

The last major item to remove is the crankshaft. Remove the crankshaft and inspect it carefully for damage, overheating, or lack of oil. Now that all the engine parts have been removed, do a final inspection of the engine for cracks or damage. 

7. Prep For Reassembly

All reusable parts from the old engine should be thoroughly cleaned. Use a detergent made for engine cleaning to wash parts and then dry them with an air compressor. While cleaning and drying, inspect parts for damage. Clean the engine block in the same manner before rebuilding. 

Ream the walls of each cylinder to ease piston seating. When finished, coat each cylinder wall with lubricant to prevent rust. Complete reassembly preparation by replacing engine freeze plugs, installing and lubricating new camshaft bearings, and fitting new rings for the pistons. Follow the engine manual instructions for piston installation carefully to prevent future engine issues. 

8. Reassembly

Begin reassembly with the lower end of the engine. First, reseat the crankshaft, main bearings, and caps. Lubricate all parts after they are installed. Reinstall the pistons and their corresponding rod end caps. Carefully replace the camshaft, being sure to lubricate the camshaft journals and it's cam lobes. Install timing components, including the timing chain. Use the directions in your engine manual to clock your timing components properly. Reseat the oil pan and be sure to put a layer of silicone at the meeting point of the gaskets and pan. 

You can now begin reassembling the engine top half. Put in the head gaskets, head, and then head bolts. Torque the head bolts according to your engine manual specifications. Reinstall the lifters, pushrods, guide retainer, and rocker arms, lubricating each one as you seat them in the new engine. Install the covers, water pump, intake manifold, exhaust manifold, and flywheel. Finally, install all other components in the opposite order of removal. 

9. Put Rebuilt Engine Into The Vehicle

Mount your rebuilt engine onto the engine hoist and move it back into your vehicle. Keep the engine level at all times. Now that the engine is back in the vehicle, reconnect all the electrical wires, hoses, and harnesses. After everything is reconnected, fill up the engine's antifreeze and oil. 

10. Test Your Rebuilt Engine

For safety, block up the wheels and set the emergency brake. Before testing, be sure all parts are thoroughly lubricated to prevent engine failure. While testing, pay attention to the oil pressure and temperature gauges. If the oil pressure is full or anything else seems abnormal, stop testing immediately. After starting the engine, rev it to 2000 rpm and check your gauges. If the engine seems fine, run the engine between 1800 rpm and 2500 rpm for 20 minutes or more. When the engine test is finished, check the charge on your battery and pull the radiator cap to check for leaks.

After testing, it is important to take special care of your restored engine. Change the oil and filter after the first 100 to 200 miles, and then every thousand miles for approximately three months. (More on that here.)

When restoring an engine, the best tool at your disposal is patience. The engine restoration process is time-consuming and has a lot of small but important steps. Take your time and you can rebuild an engine to be proud of for years to come.