A 40-series Jeep motor, like the 4.0-liter inline-six, weighs around 400 pounds fully dressed with accessories. If you are asking “how much does a 40 jeep motor weigh” because you are planning a swap, rebuild, or just moving one around, you need the exact numbers. The weight can vary by 50 to 100 pounds depending on the specific model year and what parts are attached.
Knowing the weight is critical for selecting the right engine hoist, stand, or shipping method. A 40-series motor is not light, and guessing can lead to broken equipment or injury. Let’s break down the exact weights for the most common 40-series Jeep engines.
How Much Does A 40 Jeep Motor Weigh
The most common engine in a 40-series Jeep is the 4.0-liter inline-six, also known as the AMC 242. This engine was used from 1987 to 2006 in the Jeep Cherokee (XJ), Wrangler (YJ, TJ), and Comanche (MJ). The weight you need depends on whether you are measuring a long block, short block, or a fully dressed engine.
Weight Of A 4.0-Liter Inline-Six Jeep Motor
A fully dressed 4.0-liter inline-six includes the intake manifold, exhaust manifold, alternator, power steering pump, A/C compressor, starter, flywheel or flexplate, and all sensors. This is the weight you will deal with when pulling the engine from a Jeep.
- Fully dressed 4.0L engine: 400 to 420 pounds
- Long block (no accessories, but with cylinder head and oil pan): 320 to 340 pounds
- Short block (just the block, crank, pistons, and rods): 240 to 260 pounds
- Bare cylinder head only: 45 to 50 pounds
These weights are for the cast iron block version. The 4.0L uses a heavy cast iron block and cylinder head, which is why it is so durable but also heavy. The weight does not include transmission or transfer case, which add another 100 to 150 pounds if attached.
Weight Of A 2.5-Liter Four-Cylinder Jeep Motor
Some 40-series Jeeps, especially the base models, came with the 2.5-liter four-cylinder engine (AMC 150). This engine is significantly lighter than the 4.0L.
- Fully dressed 2.5L engine: 280 to 300 pounds
- Long block: 220 to 240 pounds
- Short block: 170 to 190 pounds
If you have a 2.5L, you can use a lighter engine hoist or stand. But always check the rated capacity of your equipment before lifting.
Weight Of A 4.2-Liter Inline-Six Jeep Motor
Older 40-series Jeeps, like the CJ-7 and early Wrangler YJ, used the 4.2-liter inline-six (AMC 258). This engine is similar in design to the 4.0L but with a different displacement and carbureted intake.
- Fully dressed 4.2L engine: 420 to 440 pounds
- Long block: 340 to 360 pounds
- Short block: 260 to 280 pounds
The 4.2L is slightly heavier than the 4.0L because of the larger displacement and heavier cast iron components. If you are swapping a 4.2L for a 4.0L, the weight difference is minimal, but the 4.0L is generally considered a better engine.
Weight Of A 2.8-Liter V6 Jeep Motor
Some 40-series Jeeps, particularly the 1984 to 1986 Cherokee XJ and Comanche MJ, came with the GM-sourced 2.8-liter V6. This engine is lighter than the inline-six but heavier than the four-cylinder.
- Fully dressed 2.8L V6: 320 to 340 pounds
- Long block: 260 to 280 pounds
- Short block: 200 to 220 pounds
The 2.8L V6 is not as common, but if you have one, the weight is manageable. However, this engine is known for reliability issues, so many owners swap it for a 4.0L or a V8.
Factors That Affect The Weight Of A 40 Jeep Motor
The exact weight of your 40-series Jeep motor can vary based on several factors. Do not assume all engines of the same displacement weigh the same. Here is what can add or subtract weight.
Accessories And Attachments
A fully dressed engine includes many components that add weight. The alternator, power steering pump, A/C compressor, and starter motor each weigh 5 to 15 pounds. The intake and exhaust manifolds add another 20 to 30 pounds. If you have a heavy aftermarket intake or headers, the weight can increase.
If you are removing the engine for a rebuild, you can save weight by taking off the accessories first. This makes the engine easier to lift and maneuver. But if you are shipping the engine, it is often better to leave the accessories on to protect the block.
Flywheel Or Flexplate
The flywheel (manual transmission) or flexplate (automatic transmission) adds significant weight. A stock flywheel for a 4.0L weighs about 30 to 35 pounds. A flexplate is lighter, around 10 to 15 pounds. If you are weighing the engine without the flywheel, subtract that weight.
Oil And Coolant
When you pull an engine, it will have residual oil and coolant inside. This can add 5 to 10 pounds to the total weight. Always drain the oil and coolant before lifting to reduce weight and prevent spills.
Engine Block Material
Most 40-series Jeep engines use cast iron blocks and cylinder heads. This makes them heavy but strong. Some aftermarket blocks are made of aluminum, which can reduce weight by 50 to 100 pounds. But factory engines are almost always cast iron.
How To Safely Lift A 40 Jeep Motor
Now that you know the weight, you need to lift the engine safely. A 400-pound engine can cause serious injury if dropped. Follow these steps to avoid accidents.
- Use a rated engine hoist: Your hoist should have a minimum capacity of 1,000 pounds. This gives you a safety margin. Never use a hoist that is rated for less than the engine weight.
- Check the chains and bolts: Use grade 8 bolts for attaching the lifting chain to the engine. Inspect the chain for wear or damage before each use.
- Remove heavy accessories first: Take off the alternator, A/C compressor, and intake manifold to reduce weight. This makes the engine easier to balance.
- Use an engine leveler: An engine leveler allows you to adjust the angle of the engine as you lift. This is especially important when pulling the engine from a tight engine bay.
- Secure the engine on a stand: Once the engine is out, mount it on a engine stand rated for at least 750 pounds. The stand should have four wheels for stability.
- Work with a helper: Even with a hoist, having a second person to guide the engine and watch for clearance is safer.
Shipping A 40 Jeep Motor
If you are shipping a 40-series Jeep motor, you need to know the weight for freight quotes. Shipping companies charge by weight and dimensions. Here is what to expect.
A fully dressed 4.0L engine weighs about 400 pounds. The shipping crate or pallet adds another 50 to 100 pounds. So the total shipping weight is around 450 to 500 pounds. Freight costs vary, but expect to pay $150 to $300 for ground shipping within the continental US.
To save on shipping, remove all accessories and drain all fluids. A long block weighs less and is easier to crate. You can also remove the cylinder head to reduce weight, but this increases the risk of damage during shipping.
How To Crate A Jeep Motor For Shipping
- Drain all oil and coolant completely.
- Remove the alternator, starter, and other loose parts. Wrap them separately.
- Place the engine on a heavy-duty pallet. Use bolts to secure the engine to the pallet through the motor mount holes.
- Wrap the engine in plastic wrap to protect from moisture.
- Build a wooden crate around the engine. Use 2×4 lumber and plywood. Make sure the crate is sturdy and the engine cannot shift.
- Label the crate with “Heavy” and “This Side Up” stickers.
Common Mistakes When Weighing A 40 Jeep Motor
People often make mistakes when estimating the weight of their Jeep motor. Here are the most common errors and how to avoid them.
- Using a bathroom scale: Bathroom scales are not accurate for heavy objects. They can break or give false readings. Use a commercial scale or a shipping scale.
- Forgetting the flywheel: The flywheel adds 30 to 35 pounds. If you weigh the engine without it, you will underestimate the total weight.
- Including the transmission: The transmission and transfer case add 100 to 150 pounds. If you are weighing the engine alone, remove the transmission first.
- Not accounting for accessories: A bare block is much lighter than a fully dressed engine. Always specify whether you are weighing a long block, short block, or dressed engine.
Why The Weight Matters For Your Project
Knowing the weight of your 40-series Jeep motor is not just trivia. It affects every step of your project. If you are swapping engines, you need to know if your new engine is heavier than the old one. A heavier engine can affect the suspension, brakes, and handling of your Jeep.
If you are rebuilding the engine, the weight determines what engine stand you need. A stand rated for 500 pounds is fine for a 4.0L long block, but a fully dressed engine might require a 750-pound stand. Always check the stand’s capacity before mounting the engine.
If you are moving the engine across the garage, you need to know if your dolly or cart can handle the weight. A 400-pound engine on a cheap dolly can tip over easily. Use a heavy-duty dolly with a wide base.
Frequently Asked Questions About 40 Jeep Motor Weight
How Much Does A 40 Jeep Motor Weigh With Transmission Attached?
A 4.0L inline-six with the AX-15 manual transmission and NP231 transfer case weighs about 550 to 600 pounds. With an automatic transmission like the AW4, the total is around 500 to 550 pounds. The transmission and transfer case add significant weight.
Is A 40 Jeep Motor Heavier Than A Chevy 350?
A Chevy 350 small block V8 weighs about 450 to 500 pounds fully dressed. So a 4.0L Jeep inline-six is slightly lighter, around 400 to 420 pounds. The Chevy 350 is heavier due to the larger displacement and V8 configuration.
Can I Lift A 40 Jeep Motor By Myself?
You should not try to lift a 400-pound engine by hand. Use an engine hoist or a transmission jack. Even with a hoist, it is safer to have a helper to guide the engine and watch for clearance.
How Much Does A 40 Jeep Motor Weigh In Kilograms?
A fully dressed 4.0L inline-six weighs about 181 to 190 kilograms. A long block is around 145 to 154 kilograms. For metric users, always check the rated capacity of your lifting equipment in kilograms.
Does A 40 Jeep Motor Weight Change With Year?
Yes, slightly. Early 4.0L engines (1987 to 1990) have a different cylinder head and intake manifold that are heavier. Later engines (1991 to 2006) use a lighter intake manifold and a different head. The difference is about 10 to 20 pounds. The 4.2L engine is also heavier than the 4.0L by about 20 pounds.
Final Tips For Handling Your 40 Jeep Motor
Always verify the weight of your specific engine before lifting or shipping. If you are unsure, weigh the engine on a commercial scale. Many auto parts stores have scales for this purpose. Do not rely on internet estimates alone.
When using an engine hoist, make sure the boom is fully extended and the legs are spread wide. A top-heavy hoist can tip over with a 400-pound load. Always lock the casters before lifting.
If you are storing the engine for a long time, keep it on a stand in a dry area. Cover it with a plastic bag to prevent dust and moisture from getting inside. Rotate the crankshaft by hand every few months to prevent the rings from sticking.
Knowing how much a 40 Jeep motor weighs is the first step to a successful engine project. With the right equipment and safety precautions, you can handle the weight without problems. Whether you are rebuilding, swapping, or just moving the engine, the numbers in this article will help you plan your work.