1:2 Scale John Deere Model A Engine

[LegoLord1880]

Here is a scale model engine I made, inspired by Digitaldan's 1:1 scale engine. Before I get into the LEGO version I made, let me tell a few things about the original:

The John Deere Model A was a row crop tractor built from 1934 to 1952 in three generations: Unstyled, Styled, and Late Styled. It was a direct competitor to the Farmall F-20 and later the Farmall H. The engine was a transverse mounted inline 2 with a 5.5" bore x 6.5" stroke, for a total displacement of 309 ci (5.1 Liters!). Governed speed was 975 RPM. These engines were notorious for being extremely loud, and vibrated a lot with terrible power delivery. In my opinion, the only reason John Deere stayed in business was because their tractors were cheap to run. In 1934 a model A on steel wheels sold for $1,025. The comparable Farmall F-20 on steel sold for $900-$1,000 in 1934. The difference was that because of the high compression ratio, the Deere could run on may different fuels. The F-20 started on gas and switched to kerosene when warm. 

My model has 8x8 square pistons and a 10 stud stroke for a total displacement of 655 cc. The crankshaft is built out of 6x6 round bricks and incorporates engine1ear's caged bearing system. I built the model in Studio 2.0, and it consists of 12 separate modules: The block, crankshaft, cylinder casting, camshaft, head assembly (including valves), flywheel, 2 pistons, and 4 pushrods. All these modules add up to a grand total of: 2366 parts! 

https://www.tractordata.com/farm-tractors/000/0/2/25-john-deere-a.html

Why only two cylinders? 

 

Edited February 3 by LegoLord1880

[engine1ear]

Wow, it's cool to learn more about the tractor engines that my grandfather used to hot rod for competing in the tractor pulls from a post in a LEGO forum. I really appreciate how you did your research and how the scale of this engine is really close to 1/2. It's also cool to see you utilizing the caged bearing idea, though it's too bad you don't have the parts to build this and see them in action. I've been very impressed with how they have performed for me :D

I think your vision for making it a four stroke engine is also cool. Were the original engines chain-driven? Perhaps the 21 and 42 tooth gears from the 1960s could get you the 1:2 ratio needed if you can settle for no timing chain. The vintage chain links only work with the 1970s gears, and they don't have a 1:2 combo unfortunately for us.

[LegoLord1880]

THX!!!     

I went with the 4 stroke design for realism, and to preserve the engine's unique sound when running. Because of the 180 degree crank, it fires twice and then "misses" twice. Also, the original had a gear driven camshaft. I went with a chain because I ran out of space inside the block lol.