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New 4 Cylinder Engine Bare Block
Fits 41-53 Jeep & Willys with 4-134 L engine (Out of Stock)

Part # 641145

New 4 Cylinder Engine Bare Block

Finally the 4-134 L engine has been reproduced!!

All machined surfaces are milled to original design specifications. Block includes: Valve guides; hardened valve seats, NPT threaded oil galley plugs, freeze plugs and camshaft expansion plug.

- Cylinder Bore: 3.1255 +/- .0005
- Valve Guide  Bore Diameter (In & Ex): .374 +/- .0005
- Valve Seat Surface Width: .09375? to .125 +/- .0005
- Tappet Bore Diameter: .626 +/- .0005
- Oil Galley Taps/Plugs:  NPT 1/8 & NPT 3/8
- Oil Galley Taps - Tapered

The machining operation is using automated CAD CNC machining with tolerances exceeding .0005 inches-far more precise and exceeding the tolerances of American-made '40s Willys engines.

Sample blocks were completely maped on a Coordinate Measuring Machine (CMM) and created a 3-D drawing in Solid Works to begin the process. The CMM factory used can measure up to 1.5 micrometers in accuracy (0.000059").

In effect, they reverse engineered the 4-134 L engine block and set it up as such. Instead of using a green sand casting as the original blocks were made, they used the investment cast method for more structural integrity and durability, as well as surface finish and machining surfaces, even though it is more expensive. In addition, the new grey iron blocks have a higher content of chromium and copper for added strength and durability over the original design.

About of the 4-134 L Engine Block / Warranty Information

Test Run Operations Log

YouTube Build Your Willys: Engine

Each block has an individual serial number.

They are each coated with a rust inhibitor and shipped in a wooden crate and come with a warranty and general prep information and each has an inspection tag with critical specs.

4-134 L engine  (GEAR TO GEAR)

41-45 MB
41-45 GPW
46-49 CJ-2A
49-53 CJ-3A
50-52 M38
46-49 Truck
46-49 Station Wagon
48-49 Jeepster


Part # Price





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Questions & Answers

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What is the current availability for a flathead L134 block?

Willys Jeep Parts Tech:
Please email mike@kaiserwillys.com on.

are the L blocks and the F blocks the same ?

Willys Jeep Parts Tech:
They are two different blocks for L and F heads.

Hi there, is the block now available and will you ship to Germany ? Regards Christian

Willys Jeep Parts Tech:
Please check with us in 2023

Hi Are the 4-134L Engine blocks back in stock now? I believe they were not available during the 2020 & 2021 after the onset of Covid. Let me know if it is possible to source the new blocks. Best Regards, Hafees

Willys Jeep Parts Tech:
Check in with us early 2023

Hi Mike, Are these Blocks made in USA? (Not China in other words).

Willys Jeep Parts Tech:
Please read our extensive links on the blocks and their manufacture in the links in the item description. Thanks!

I have a 4-134F head engine with a engine serial number of 4J 401707, lam trying to find out the year and what jeep this engine might have been put in from the factory. Thank you

Willys Jeep Parts Tech:
Email mike@kaiserwillys.com to help out.

Will there be a F-134 bare block coming out soon? Thanks

Willys Jeep Parts Tech:
Possibly in 2022

Now that the blocks are in good supply, will you be offering crated, pre-run in, long block assemblies in the future?

Willys Jeep Parts Tech:
Sorry, not at this time.

I am looking for a used L-134 block for a 1952 Willy's Station wagon. I am in Montana. Any idea where I might find one?

Willys Jeep Parts Tech:
We can give you some numbers for salvage yards. Email mike@kaiserwillys.com

Is this block chain driven or gear driven?

Willys Jeep Parts Tech:
Gear driven. Thanks

Is this for overhead valve or flat head models?

Willys Jeep Parts Tech:
L head the flat head.

Hello, I am looking for an engine bare block for the F-134 hurricane (Willys CJ5 1960) ¿Is there any available? Thank you.

Willys Jeep Parts Tech:
They are in development for next year. But in the mean time we can help you with good used if like.

Will you be making a 6-226 engine in the future?

Willys Jeep Parts Tech:
Right now we can help you with good used for the 6-226 engine

Is it possible to get on a wait list for one of these blocks? My son's ride is down with a cracked block. Thank you.

Willys Jeep Parts Tech:
We will do a big announcement on them. Sign up for our newsletter online. Thanks!

Would it be possible to send the preparation information for item 641145 bare engine block L4-134 to the email williammharkins@sbcglobal.net

Willys Jeep Parts Tech:
See our links on information on the item itself. There are two links on the item 641145 about it. Please let me know if you have any questions.

When will these blocks become available? Can I reserve one? Brian Peterson

Willys Jeep Parts Tech:
Please check back in with us around the beginning of September. We should have, at least, some sort of date by then. Thanks

Did they fix the cracking issue under the distributor? (Made the wall thicker?) or did the better casting and improved metal mixture solve that problem?

Willys Jeep Parts Tech:
There has never been a cracking issue on these new blocks. Possibly on the originals Willys made but not these.

30 weight?

Willys Jeep Parts Tech:
10W30 is what was originally used.

4 134L, will there be a short or long block offer

Willys Jeep Parts Tech:
Sorry, nobody is doing that currently.

Is there anyway we can order an engine with a blank serial number or have our serial number added to the engine block?

Willys Jeep Parts Tech:
Sorry, they are not able to do this.

When will Cylinder Engine Bare Block 1954 Jeep & Willys Kaiser CJ3B 4-134 F engine?

Willys Jeep Parts Tech:
Those hopefully will be finished in development next year.

Dose the block have hardened valve seats? Or do you have to run a led additive in the fuel?

Willys Jeep Parts Tech:
Yes, they will have hardened seats.
Willys Jeep Parts Tech:
Yes, they will have hardened seats.

Will the engine you’re working on for a 1954 CJ3B?

Willys Jeep Parts Tech:
Yes, it would fit under the hood of a CJ-3B since this is a flat head and the CJ-3B had a high hood to accomodate the 4-134 F head motor.

Do you know if there will be an engine bare block for the F-134 hurricane will be made?

Willys Jeep Parts Tech:
Yes, we are currently working on it now. We are hoping to have it ready by the end of the year. Thanks

What is the recommended oil wt. to be used with a built up Allied block? Can I use a synthetic?

Willys Jeep Parts Tech:
We typically use non-detergent oil - 30 or 40. Thanks

Is a price for complete engine l134.... long block disassembled.

Willys Jeep Parts Tech:
This price is as shown with the information above. It is a bare block.

does the block have to be bored out are they bore to size

Willys Jeep Parts Tech:
No, it does not have to be bored. See spec sheet and links above. It is std. size 3-1/8"

What is the weight of the bare block?

Willys Jeep Parts Tech:
These blocks weight approx. 88#. Thanks!

What is the cost of a complete L134 bolt on engine???

Walter Andreis:
This is a bare block motor. We can build it up with an engine overhaul kit and anything else you need. But the assembly of it you have to do from your location.
Willys Jeep Parts Tech:
We have blocks, engine overhaul kits, crankshafts, camshafts, ect. Please call and ask for Mike M. I can work it up for you.

What would be the total cost of all the parts needed to build a brand new engine with this engine block if purchased through you?

Willys Jeep Parts Tech:
Please call us toll free. There are a lot of variables there depending on what all you really need and currently have.

Do you sell the gear drive front engine plate for this block? I want to do a reproduction gpw.

Willys Jeep Parts Tech:
We can get those good used. Please call us toll free. The A1463 should bolt up as well.

Are you going to do the same with the 4-134F engine?

Willys Jeep Parts Tech:
They are working on it now.

It looks like this engine will fit a wide variety of military and civilian jeeps. How much does it differ from an original MB or GPW block and what additional parts are required to get a running operational block?

Be the first to answer this question.

Hello, The shipping price to Marseille in France ? Thank you. Mike.

Willys Jeep Parts Tech:
Please email mike@kaiserwillys.com your full shipping address and the part number and quantities you need and we can quote you out. Thanks!

what color was the engine painted originally from the factory?

Willys Jeep Parts Tech:
Typically they were black if civilian and OD green if military.

Will all of the original motor accessories, fuel pump, generator mounting bracket etc. for an 1952 M38 military jeep bolt on to this block with out additional modifications

Willys Jeep Parts Tech:
Yes, it will. This is a 4-134 L gear block.

are the cam bearings installed?

Willys Jeep Parts Tech:
There is only 1 camshaft bearing on a 4-134, they are separate part number: 645595

Can we now build a complete brand new l head with parts from your store? Can I get the vin number from my 3a stamped on my new block from the factory, this would allow me to have a number matching jeep? I could supply a copy of my motorized title and any other info needed. My stock engine was stolen during the rebuild.

Willys Jeep Parts Tech:
We can help you out with pretty much everything from start to finish. These are pre stamped at the factory, so you cannot get the numbers of your old engine put on.
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