Wonders never cease, a new L-134 flathead has arrived

(Continue to check in for updates which will be posted and dated at the bottom of this article. Happy Jeeping! -Merlin)

We are not talking about a rebuilt engine here, we are talking about a brand new fresh out of the foundry L-134 engine block. Yes, really, they now exist. Commence celebrating.

In a story reminiscent of the old days of Jeep an enthusiast has done what he was told was impossible.  New L-134 flathead engines have left the foundry and the first prototype is undergoing testing.

L-Block - Prod - 1

A man with extensive manufacturing experience, John, began wondering a while back about the availability of the flathead engines that drive our ancient Jeeps.  From experience in our restoration shop I can say I often have concerns when a vehicle arrives with a questionable engine.  Many can be saved, but there are many with cracked blocks or issues that require extensive time with a machinist to bring them back to reliability. And I know we all have seen the bumps in the hoods where F heads were installed for lack of a flathead.


Noting the lack of replacement engines, and the passion in the community for keeping these old flat fenders alive John used his experience and resources and set about doggedly pursuing the goal of making new L-134 blocks again. Having extensive experience with manufacturing overseas he set about looking for a foundry that had the capability to produce this engine in the quality that Jeepers need and expect.

Like any good adventure John was told that his quest was impossible (reminds me of many of our inventors back in the early 20th century!).  No foundry could make the quality engine needed in low numbers.  Factories said the same, they couldn’t do it.  But John worked on and convinced a foundry they could do what he wanted and then set about the backwards engineering of an L-134.

In this process John contacted me and told me of his plans.  To say I was initially incredulous is putting it lightly.  I have met so many people with great ideas but bringing them to fruition is rare.  John came by my shop with an old flathead compressor set up he bought for a testing bed for his engines and I could see he meant business. The result is in the video below.

Test results so far have been the following (from John’s test logs). The engine has been both run on its test bed, and tested under loads in Johns CJ5.


So far things look good with the new engine!  Now we need to find people to sell it.  When we get enough orders then production can begin.  Pricing will be reasonable and should save you time going to a machine shop, finding out your block has hairline fractures and then searching for a new block.  Any parts dealers who are interested please contact me at merlin@hansonmechanical.com for more details.

To say this is exciting is an understatement.

Update 8/21/16: 

L4-134 Engine Block – READY TO ASSEMBLE – is cast in hardened gray iron. All machined surfaces are milled to original design specifications. Block includes: Valve guides; hardened valve seats for intake and exhaust valves; NPT threaded oil galley plugs, freeze plugs and camshaft expansion plug. Blocks are coated with a rust inhibitor wrapped in protective plastic and are packed with assembly preparation instructions. Each block is individually serialized with the number stamped into the machined deck surface.
– 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.
Update 2 8/21/16
On metallurgy.  The cast iron is upgraded grey iron with higher chromium and copper content and with higher grade iron than the original.  John had an original block sampled and tested.  New is harder and more durable. Seated intakes and exhaust. Nice tolerances on valves straight out of the crate.
On production location.  The engine is being produced in China.  Please note that there are high quality ways and cheap ways of making items in China.  This engine is made in a region that produces many engines for the Japanese auto industry.   Machining is done on CNC machines with tolerances of 10,000th of an inch.
On the process.  The development of this engine has been a hands on process, John has been to China 6 times in the last year working on development of this engine.
L-Block - Prod - 3