Old Car Engine Repair and Restore
Does My Engine Need A Rebuild?
Just because the engine in your classic car is old doesn't mean it needs a rebuild. It may only need minor repair that can be done without pulling the motor out. To determine what is the best course of action, consider the following engine conditions and symptoms.
Excessive Oil Consumption - Years ago, I had a 1971 Camaro that burned a quart of oil every 250 miles. Turns out a piston ring was broken. Anything more than a quart every 500 miles tells you something is wrong.
High Mileage - On a 1970s or older car, that's anything over 100k.
Poor Engine Compression - Readings 30-35 psi lower than specs indicates worn rings or valves (or both). One or more cylinders that read considerably lower than the highest one tells you those cylinders are most worn. It's always best to do a compression check when the engine is warm, but it can still be performed if the engine doesn't run. It just needs to be able to crank at normal speed.
Poor Fuel Mileage - It might be hard to tell on a large V8, but anything below 10 mpg on the highway is probably a good indicator the engine is old and tired.
Minor symptoms by themselves may be repairable without pulling out the motor and doing a complete rebuild.
Sometimes you don't have a clear indicator of whether or not an engine needs a rebuild, but if you have several minor issues (for instance, bad mileage and oil consumption), it may a good idea to rebuild the entire engine.
Can I Rebuild An Engine Myself?
If you decide that a complete engine rebuild is necessary, ask yourself, "Can I rebuild an engine myself?" Here are some points to consider.
A Garage - You will need a clean place to work in, well-lit and secure. You'll be leaving various engine parts around, so try to keep people out as best you can without offending them!
Mechanical Ability - Some people are naturally mechanically inclined. My guess is that if you're reading this, you are.
Tools - Aside from basic hand tools, you'll be needing a piston ring installer, a torque wrench, dial caliper, feeler gauge, harmonic balancer remover and installer, etc.
Patience - There are many small steps in engine rebuilding, each as important as the others. It could become long and complex, particularly if parts are hard to find. You need common sense and you need patience. Engine restoration is not for those who need instant gratification. For those, I suggest buying a crate engine and being done with it.
Never Take Anything For Granted - Rebuilding your old car engine requires measuring and re-measuring, assembly, disassembly, and reassembly. Make sure everything is right before continuing to the next step.
There's a few outside sources needed while restoring your engine, which include a parts supplier, a tool supplier, and a machine shop.
Shop Manual - When restoring an old engine back to new condition, a factory shop manual for your make and model car is invaluable.
Machine Shop - Without expensive, dedicated equipment and a lot of experience, you'll need to farm out steps such as block boring, crank and rod balancing, and cylinder head rebuilding.
Parts Supplier - It seems like good auto parts stores and good parts guys are becoming a thing of the past. That's where the internet helps the old car hobbyist. There's plenty of reputable on-line stores. (see Classic Car Resources)
Before you order that crate motor and have it delivered to your door, consider this: The original rebuilt motor will not only add value to your classic car, it will award you style-points no pre-fab motor ever will.