Q: Hello Vette technical department. My name is Charles and I have a question regarding my 1976 Corvette, which is a daily driver. My engine is tired and starting to burn oil. I am not interested in keeping the car original and I just enjoy using the vehicle for an everyday driver with some cool styling. I am looking at a company that sells remanufactured engines and a competitor that sells rebuilt engines. I think remanufactured or rebuilt means the same thing. There is quite a price difference between the two engines so I want to make sure that I am not comparing apples and oranges. If you have any other recommendations please let me know. Hoping to be back on the road soon. Thanks.
A: This is a good question and one I get a lot when readers are faced with a major auto repair such as an engine, transmission, or differential replacement. To make an educated decision you will need to be able to identify the differences between a remanufactured and a rebuilt part.
Yes, there is a difference and many people confuse remanufactured products with rebuilt ones, and some people assume that a used product will be a viable replacement alternative to their failed engine, transmission, differential, or other component.
Whatever the term you use for the part you’re having replaced in your vehicle, you should make sure that you’re getting the exact part you’re expecting. Now let’s identify the differences between remanufactured and rebuilt components:
To remanufacture means to make the part as close to new as possible. A remanufactured part is one that has been completely manufactured to the standard of a new part. If the part has wearable components, those are automatically replaced. All core material is closely inspected and checked against original equipment specifications for correct dimensional tolerances. Most replacement parts are new or inspected used parts. If new, the parts should be made in the same production processes as original equipment and testing should be performed to manufacturer specifications and original production standards. If used, the part should be cleaned and inspected for any wear, stress cracks, or and other defects before it is used.
On a remanufactured engine the mechanical tolerances should be restored either by re-machining or by installing the necessary inserts to restore the unit to its original mechanical tolerances. Either way, the engine should meet the standard for OEM tolerances, durability, and quality.
New pistons, connecting rods, rings, bearings, camshafts, lifters, and oil pump should be installed. All related bearing surfaces are restored and the upper half of the engine—such as the cylinder heads—should be rebuilt. Usually the only component from the old engine that is used is the block. This part should only be reused if it is in rebuildable condition.
These same rules should apply to other remanufactured auto parts, whatever they may be. You will find that remanufactured auto parts usually carry a longer warranty than rebuilt parts.
To rebuild is to recondition a part by cleaning, inspecting, and replacing only worn or broken parts. Serviceable parts are reused if they fit within the manufacturer’s acceptable wear limits. The quality of rebuilt components varies from one rebuilder to another and many only come with a limited warranty.
Before rebuilding, all of the components within the unit are equally worn. After rebuilding, some of the components could be new, some could be from a different used unit, and some of the components could be original. The thing to remember is that the “used” components may still function properly and do not need replacing, but they are still worn to some degree.
There are other factors that can cause wear so as not to be visible to the human eye, such as heat stress and cracks. Consequently, this could cause other problems with the part, resulting in premature failure. There have been many instances where I personally have installed up to three rebuilt engines before getting one that actually worked correctly. This is even more common on rebuilt electrical parts.
This brings us to another term that is sometimes misunderstood: “core.” This is when you exchange your broken part for one that has already been rebuilt. A core for a rebuilt part such as an engine may also be referred to as the casting.
For example, if an engine is rebuilt, maybe just the bearings and piston rings needed to be replaced. So the original crankshaft, pistons, and connecting rods were still in good shape and would be reused instead of using new or ones. The final result will usually save the customer money up front. Just remember this rebuilt part is just that and may fail sooner than a new part would. So if you don’t mind possibly changing the part out several times if there is a problem and want to save a few dollars, this could be the part for you.
Used Engines, Transmissions, and Differentials
Used components are pulled directly from a vehicle, normally from a salvage yard unit. In some cases the part has not been tested and the surface may not have been cleaned, unless you count being rained on as a cleaning cycle.
There is generally no quality control for salvage yard parts. There are no provisions for disassembly, internal cleaning, or inspection with a used part. You don’t know what you are getting. Used or junkyard parts may have high mileage and the vehicle they came off of may have a poor maintenance history. Some used or salvage yard parts come from a vehicle that was involved in an accident and may have unseen damage.
There are some things you can do to try to ensure you are getting the best quality used part available. When selecting a salvage yard from which to purchase a used auto part, look the place over. Is the yard clean and well organized? What kind of cars does the salvage yard have in its inventory? Are the vehicles in the salvage yard totaled vehicles? Are the cars old clunkers open to the environment? Have the parts been removed from the vehicle and stored in a shelter, protected from the elements? Or are they just lying in the weeds? You do not want to purchase delicate electrical components that have been lying out in the weather and then picked up off the ground and sold to you.
Some salvage yards run the vehicles if possible when they come into the yard and then remove parts that they do not want exposed to the elements and inventory them in an organized dry storage building on the premises, with everything neatly stacked and categorized.
There are many respected salvage yards that take pride in their businesses and in serving their customers. This kind of salvage yard is especially careful when buying certain used auto parts, specifically engines, transmissions, differentials, and, in particular, electrical parts.
If you are looking for a hard to find part for your Corvette some salvage yards use computer systems to cross reference parts with a network of salvage yards across the region or even the nation.
You may find that vehicles of the same make and model share common parts failures, this is especially true with electrical parts. If you purchase a used electrical part it probably will have a limited life before it fails as well. Another thing to remember when selecting a salvage yard part is to ask about a warranty and return policy.
So What Part Should You Choose?
One of the first things to consider when selecting a rebuilt, remanufactured, or used part is to determine how hard it is to replace the part. How willing would you be to replace a particular part multiple times? For example, you will only want to replace the engine once because it is a labor intensive job. Purchase the best part available so you will only need to perform the job once. If you are replacing a mass air flow sensor you may want to save a few dollars and if the part fails it’s not hard to replace.
Another factor to consider when purchasing your part is to first determine exactly what plans you have in mind for your vehicle. Do you plan on keeping the vehicle long term or do you need a part to get you by until you can sell the vehicle or raise the funds to repair the vehicle correctly?
I also like to deal with a local vendor instead of purchasing parts off of the Internet. I have had good luck with Internet vendors standing behind their parts, but the downtime of the vehicle during shipping sometimes is an inconvenience. If time is not a factor sometimes the Internet can save you money. Just remember that when selecting an Internet vendor to ask about the warranty and return policy. Also, deal with well-known companies that have good reviews.
Charles, I always use new OEM parts when available. Trust me; it will save you a lot of time and headaches in the long term. All these factors come into play to help you make an informed repair decision. I hope this helps and good luck with your engine swap.
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