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Vintage Jeep Engine Blocks now Available!

Posted in Features on August 22, 2016
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Photographers: John Lampl

Truth be told, old flathead Jeep engines are getting hard to find. And since the Willys four-cylinder flathead is the heart of the Jeep, it only makes sense to make new blocks available. At least that’s what John Lampl figured when he was rebuilding his old Jeep and found that the engine block was cracked. In some cases, a cracked block can be fixed, but other times, it’s just not cost effective or reliable. In fact, the supply of good used core engines are so slim that John’s machinist stated the he “could use 20 a month” if they were available. That got John thinking about reproducing the Go Devil engine block so he and other enthusiasts could have a cost-effective alternative.

John’s background is in manufacturing and marketing, and much of his experience came from the overseas companies that do quality work for major car manufacturers. He set out on a fact finding mission to see if an engine block could be produced in the US or abroad, and what it would entail. While not a machinist himself, John worked with many of the right people to figure out how to get this project done. He found that while anything could be built in the US, the cost effectiveness would not be there, even at high quantities of production. In the United States, many of the smaller foundries found they could not compete with the large industrial makers who use more cost-saving automated processes. The downside of this that the large American foundries/factories have put the “Moms & Pops” out of business and cannot serve the lower-quantity demands of the vintage markets like for the old Go Devil. The sad fact is that we have lost manufacturing diversity to other countries, and to get what we want at the price we want to pay, we have to reach out to other countries that still have those resources. In addition, while these new blocks are made in China, it’s the quality side of that equation that results in a good product. The Chinese manufacturing base is much like that of America in the ’40s and ’50s as far as a great diversity of resources. The upside is that all of these little factories and foundries are using 21st century technology in production. For example, John’s 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. It’s the best of both worlds.

First, John found a foundry willing to produce the small quantities of blocks he envisioned; this isn’t a 10,000 unit production run - at least not yet. Then he had to find the right machining company to precisely CNC machine the castings to his exacting specifications, and also guarantee the repeatability. With the groundwork laid and a business plan made, John took some old blocks over to the foundry to completely map them on a Coordinate Measuring Machine (CMM) and create a 3-D drawing in Solid Works to begin the process. The CMM John’s factory used can measure up to 1.5 micrometers in accuracy (0.000059”). Fortunately John had some in-house help, his daughter Sunnie, a recent graduate of MIT with a mechanical engineering degree was there to look at the design process and advise him throughout the course of development.

In effect, they reverse engineered a ’52 CJ-3A 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. He also had them tested by SGS, as well as having his own machinist measure, check, and build the first test units.

Fortunately for the hobby, John reports that, after building an engine with the new block, then installing it in his CJ-5, it is up and running and passing all the tests, Of course, final price to the retail buyer will depend on how many units he can produce and sell, but for now, we believe it will be very affordable for a ready-to-go block. Merlin Hanson of Hanson Mechanical Restoration is working with John and is responsible for bringing the block to the market and to distribution. Merlin is well known in the vintage Jeep world and was the first to post about these new blocks on hansonmechanical.wordpress.com. It immediately created quite the stir, as this has been the one important item that hasn’t been reproduced for Jeeps, while bodies, frames, and most other parts have been. As the project continues, we will be at the forefront bringing you the latest details of the greatest Jeep engine ever produced: the Willys Go Devil!


The block was reverse engineered using a Coordinate Measuring Machine and Solid Works programing. Using old blocks and sawing them in produced lots of data.
The new blocks are finished machined and ready for assembly. Hardened intake and exhaust seats are already installed as are the freeze plugs and cam plugs. The blocks are coated and wrapped in plastic for delivery.
Each block is individually serialized with the number stamped into the machined deck surface in front of the block. Machined specs are: Cylinder bore: 3.1255 +/- 0.0005 Valve guide bore diameter: 0.374 +/- 0.0005 Valve seat surface width: 0.09375 to .125 +/- 0.0005 Tappet bore diameter: 0.626 +/- 0.0005″
All of the machining operations are performed on highly accurate CNC machines. Notice the cast block number preceded by JF to indicate what the foundry is.
These blocks should perform far better than a rebuilt block, as they start at standard dimensions. They are for a CJ-2a and 3A, as they are of the timing gear design, not timing chain style
Installed in a CJ-5 test bed, the reports are clear that the new block works as good as, if not better than the original. Further testing will include dyno work as well.


Original Specifications:

Specifications: Willys Go-Devil, L134 engine
Production Dates: 1938-1965
Type: Inline four, L-head
Displacement: 134.2 ci
Bore & Stroke: 3.125 by 4.38 in
Gross Power: 60-68 hp @ 4,000 rpm
Net Power: 54 hp @ 3,800 rpm
Torque: 105-109 lb-ft @ 2,000 rpm
Compression Ratio: 6.48:1 (7.0:1 in some applications)
Engine Weight: 365 lbs (bare)

Sources

Hanson Mechanical
hansonmechanical.wordpress.com

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