Automobile engine replacement

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A replacement automobile engine is an engine or a major part of one that is sold individually without any other parts required to make a functional car (for example a drivetrain). These engines are produced either as aftermarket parts or as reproductions of an engine that has gone out of production.


Replacement engines are used to replace classic car engines that are in poor condition or broken, or to install a more powerful or more fuel efficient engine in a vehicle. Replacement engines are often used to make old cars more reliable for daily driving. Classic car hobbyists may also install reproductions of a rare powerplant in a classic car (this is most often seen in Mopar muscle cars that have the 426 Hemi installed into them).

Aftermarket engines are used in many forms of motorsport. Some late model racecar series use "crate engines" many of which are made by independent firms.[1] This ensures that drivers all have similarly powered racecars. Legends and Allison Legacy Series cars also use sealed crate motors.

Types of replacement engines[edit]

The four most common types of replacement engines are: [2]

  • Remanufactured engines (also known as "re-manned," "reconditioned," or "re-engineered")
  • Rebuilt engines
  • Used engines
  • New engines (also known as "crate engines")


  • Short block - everything between the cylinder head and the oil pan (excluding those items)
  • Long block - a short block, with mounted and gasketed cylinder head, valves and camshaft
  • Crate engine - a new or remanufactured engine, considered to be equivalent to a new engine.[3] Parts include more than a long block, including intake manifold, and carburetor or fuel injection system, oil pan, valve covers, and perhaps an alternator

Short block[edit]

This is a 3S-GTE shortblock on an engine stand waiting to be cleaned.
The same engine after cleaning. Carbon deposits can be removed with a wire brush and the surface is then polished with a very fine sandpaper. Many times this work is done by a machine shop as part of a more involved engine rebuild. Rebuilding an engine helps restore power and economy and/or improve or increase performance

A short block is an engine sub-assembly comprising the portion of the cylinder block below the head gasket but above the oil pan.[4] An in-block cam engine includes the camshaft, timing gear, and any balance shafts. Overhead cam engines don't include those parts. They appeared post-war when mass production of consistent engine models became widespread, rather than hand-building of varying engines. While they were common from the 1950s to the 1970s, but disappeared after this, as when overhead camshaft (OHC) engines became the norm, the rational unit of replacement became the long block.

A short block engine is a replacement component for use when a worn-out engine requires major servicing, usually beyond the capabilities of a local repair garage, and instead a machine shop is needed. The short block represents the major wear items of such an engine: piston rings, and potentially a rebore of the cylinder bores or replacement liners, together with reground bearings on the crankshaft. Although replacing the rings or bearing shells was at one time considered typical garage work, the need for a boring or crank grinding machine exceeded the capabilities of a standard automotive repair garage. A short block represented the set of major parts needed, those beyond the garage capabilities, in one item.

The third item sometimes requiring machining, the re-cutting of valve seats in the cylinder head, was less frequently needed. Grinding of valves to fit was a regular garage task, as was light re-cutting with hand tools, usually into a cast iron seat. Once steel seat inserts came into use, either for unleaded petrol in the 1970s or fitted into aluminium heads, then machining of heads and the replacement of seats became equally commonly required. Aluminium cylinder heads could also be damaged by warping after overheating, often requiring machining to re-flatten them.

A short block would have advantages over dismantling the engine and sending the crankshaft and other related automotive parts away for rework. It would be quicker to obtain, requiring only a single shipping, rather than shipping twice and the time for machining. The short block would also have been built in a workshop hopefully cleaner and more organised for the specialism of engine building.

Short blocks were OHV engines. Sidevalves were pre-eminent before the short block appeared as a common item, and they also offered little saving by omitting the (simple) head.

Long block[edit]

A long block is an engine sub-assembly that consists of the assembled short block, crankshaft, cylinder head, camshaft (usually), and valve train. A long block does not include the fuel system, electrical, intake, and exhaust components, as well as other components. A long block may include the timing cover, oil pan and valve covers.

A long block engine replacement typically requires swapping out parts from the original engine to the long block. These parts include the oil pan, timing cover, valve covers, intake manifold, emission-control parts, carburetor or fuel injection system, the exhaust manifold(s), alternator, starter, power steering pump (if any), and air conditioner compressor (if any).

Crate engine[edit]

A "crate engine" or "crate motor" is a fully assembled automobile engine that is shipped to the installer, originally in a crate.[3] Crate engines are manufactured by many different companies, but they all share the same characteristics of being complete engines ready to install once removed from the crate. Generally a crate engine only needs bolt-on accessories such as water pump,[clarification needed] fuel system[clarification needed], and exhaust. This type of engine has various applications including general replacement, hot rod builds, and motorsports competition.[5] Crate engines are often seen as an economical and more reliable solution as opposed to engine overhauls or custom builds. Such engines are built by specialist engine builders, working in clean and well-equipped workshops, rather than general purpose repair garages.

Crate engines may be either brand new, or substantially rebuilt. If rebuilt, they will have been rebuilt to an extent such that they are considered to be of equal quality, reliability and expected lifetime as a new engine.


Crate engines are well suited in many different vehicle platforms. Engines are often used in the following applications:

  • General automobile engine replacement
  • Custom hot rod street builds
  • Marine engine replacements
  • Motorsports Competition (Asphalt, dirt track, drag racing etc.)


Crate engines are often seen as an economical choice no matter what the application is. In general automobile engine replacement, a crate engine is often very competitively priced when compared to the cost of a full rebuild of a faulty engine. It is also quicker to ship from stock than to wait an equal time for parts, then to begin a rebuild. Installers often opt for the crate engine because of the cost and ease of replacement. Crate engines are typically a bolt-in replacement with no internal work being performed to the engine compared to a complete overhaul that requires internal part replacement by trained mechanics. Hot Rod and other custom street applications also often choose a crate engine because of the higher value when compared to a custom built engine.

In motorsports, the crate engine option has become very popular for various reasons. Crate engines are often a more affordable option when compared to a purpose-built race engine so budget racers often go this route. The crate engine also has developed a large fan base in many different racing series because of the competitive racing. As all racers in the field have identical engines, the races are won by driver's talent and chassis setup, and not the amount of horsepower a team can afford to build into their engine.

EV crate engines[edit]

Most resto-mod EV conversions are achieved by repurposing drivetrains from an existing mass-produced EVs, such as Tesla. In October 2019 there were no purpose-built crate engine EV kits available for commercial use, but such projects were in development.[6] In November 2021, Ford Motor Company released a 210 kW (281 hp) crate EV motor. As of 3 November 2021, it was available for pre-order but not yet shipping.[7]

Common crate engines used in North American racing[edit]

Open Wheel Modifieds are a common type of application for crate engines

General Motors began developing several small block crate race car engines in 2001 and they were released into production in 2002. The engines are sealed and repairs being done by certified rebuilders.[8]

Chevrolet 602[edit]

The Chevrolet engine debuted in 2002 with part number 1958602 and sold for a little under $4000 in 2012.[8] It has 350 cubic inch displacement via a 4.000 inch bore and 3.480 inch stroke.[9] The 602 engine is equipped with iron heads, a cast-iron block, and aluminum pistons.[8] It produces about 350 horsepower and 390 foot-pounds of torque at 9.1:1 compression.[8]

Applications for this engine include: IMCA Hobby Stock, IMCA Northern Sport Modified, IMCA Southern Sport Modified,[10] Mid-American Stock cars.[11] Northeastern (United States) Sportman,[12] Crate Racing USA,[13] and others.

Chevrolet 603[edit]

The Chevrolet engine has part number 88959603.[14] It has 355 cubic inch displacement and 405 foot pounds of torque at 10.1:1 compression.[14] The 603 engine is equipped with aluminum heads, steel crank, and high silicone pistons.[14] The American Canadian Tour (ACT) late model sportsman utilize this engine.[15]

Chevrolet 604[edit]

The Chevrolet engine debuted in 2002 with part number 88958604 and sold for about $5000 in 2012.[8] The 604 engine is equipped with aluminum heads, forged steel crankshaft, and an aluminum intake.[8] It produces about 400 horsepower and 400 foot-pounds of torque with a 9.6:1 compression.[8]

Applications for this engine includes IMCA Modifieds (starting in 2013),[16] CRA All Stars Tour (allowed but not required),[10] United Crate Racing Alliance,[17] Big 8 Series,[18] RUSH Late Models,[19] Crate Racing USA,[13] and others.

Ford 347[edit]

Ford Performance 347 Cubic Inches 415 HP Sealed Racing Engine[20]

Replacement blocks[edit]

New castings of some engines are sometimes produced by independent companies. These blocks commonly replace rare or popular designs for aftermarket rebuilding, especially when the original is no longer produced. They are sometimes available in aluminum instead of original iron, or in stronger alloys. Often they imitate the larger available displacements that were produced in small numbers or allow for displacements never available.

See also[edit]


  1. ^ Huneycutt, Jeff. "Crate Late Model Setup - Crates On Dirt". Retrieved 3 January 2015.
  2. ^ The Most Common Types of Replacement Engines, Engine Compare Blog
  3. ^ a b Hadfield, C. (2013). Today's Technician: Automotive Engine Repair & Rebuilding, Classroom Manual and Shop Manual, Spiral bound Version. MindTap Course List Series. Cengage Learning. p. 185. ISBN 978-1-133-60251-4. Retrieved 16 June 2019. A crate engine is a new or remanufactured engine that is built with fresh components, such as bearings, rings, and lifters. You can purchase crate engines with or without cylinder heads. When an engine is mounted perpendicular to the ...
  4. ^ Jack Erjavec (2005). Automotive Technology: A Systems Approach. Cengage Learning. pp. 227–. ISBN 1-4018-4831-1.
  5. ^ Baechtel, J. (2014). Chevy Big-Block Engine Parts Interchange: The Ultimate Guide to Sourcing and Selecting Compatible Factory Parts. S-A design. CarTech, Incorporated. p. 20–26. ISBN 978-1-61325-050-1. Retrieved 17 June 2019.
  6. ^ Wood, Dafydd (17 October 2019). "Swindon Powertrain launches crate EV motor". PistonHeads. UK. Retrieved 18 October 2019.
  7. ^ "Eluminator Mach E Electric Motor ~ M9000MACHE". Ford Store. US. Retrieved 3 November 2021.
  8. ^ a b c d e f g Huneycutt, Jeff (28 March 2012). "Crate Motor - Repurposed Crate". Hot Rod. Retrieved 13 June 2021.
  9. ^ "CT 350 Circle Track Crate Engine". Chevrolet. 20 May 2018. Archived from the original on 20 May 2018. Retrieved 16 June 2019.
  10. ^ a b "New part numbers announced for GM 602, 604 crate engines". IMCA (International Motor Contest Association). 5 January 2018. Retrieved 13 June 2021.
  11. ^ "2018 Mid-American rules package" (PDF). 2018. Retrieved 13 June 2021.
  12. ^ Ellis, James A. (24 June 2021). "Racing Around: Point chase at Fonda heating up". The Leader Herald. Retrieved 26 June 2021.
  13. ^ a b "Page 1of 15National Touring Series Rules 2021" (pdf). Crate Racing USA. Retrieved 4 July 2021.
  14. ^ a b c "Circle Track Crate Engine Technical Manual" (PDF). General Motors. Retrieved 25 June 2021.
  15. ^ "ACT Late Model Sportsman 2021 Rules". Retrieved 5 July 2021.
  16. ^ "GM 604 Crate Engine Becomes IMCA Modified Option In 2013". Retrieved 25 June 2021.
  17. ^ Allen, Richard. "How much "cheating" is actually taking place in Crate Late Model racing?". Inside Dirt Racing. Retrieved 26 June 2021.
  18. ^ "Big 8 Series Rules" (PDF). Elko Speedway. 2016. Retrieved 25 June 2021.
  19. ^ Doug, Kennedy (26 June 2015). "Sweeney RUSH Racing Series Offering a Viable Option With Crate Engine Racing to Veteran Racers Throughout the Northeast". RUSH Late Models. Retrieved 25 June 2021.
  20. ^ Parts, Ford Performance (29 December 2017). "347 Cubic Inch 415 HP Sealed Racing Engine". Ford Performance Parts. Archived from the original on 29 December 2017. Retrieved 16 June 2019.

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