Free Plans: Webster Engine Work’s 4-Cycle Gas Engine

Webster Engine Work's 4-stroke Gas EngineWould you like free plans for a gas-powered 4-cycle engine that is a proven and easy-to-build design?

Joe Webster designed this engine to be quick, inexpensive and easy to build.  It doesn’t have any parts with super-critical dimensions and you don’t need a rotary table or other expensive tooling to construct it. The plans are well drawn and include two pages of construction notes.

This is what is known as a “bar stock” engine, which means it does not use any castings. It uses flat and round metal stock that can be purchased from almost any metal or machine shop supplier.  It is not a big engine so the cost of the metal should be modest.  Joe suggests making the 3.75-inch diameter flywheel out of an iron dumbbell purchased from Wal-Mart to save money.

The engine uses some components that need to be purchased, like a couple of gears, a spark plug, points, condenser, ignition coil and piston rings. The part numbers and vendors are listed on the plans and they are all readily available, I’ve checked.  Joe recommends you also buy and use a carburetor for a radio-controlled car engine, although he does include drawings so you can make one if you want.

Unfortunately, Joe’s website seems to have disappeared but you can still download the plans here. Unfortunately they are metric, in millimeters.  It looks like Mr. Webster release two sets of plans, one in US and one in metric dimensions.  His website is long gone and so far I have been unable to find the plans with US dimensions.  Please leave a comment if you have them or know where they can be downloaded. There’s a lot of interest in this engine.

Related Links:

Home Model Engine Machinist: Making the CylinderMaking the Piston – Search the site for ‘Webster Engine’ for more threads

Supplier for the Grease and Oil Cups

17 thoughts on “Free Plans: Webster Engine Work’s 4-Cycle Gas Engine”

    • could you please email me webster engine plans in english (inch)., . the measurements online don’t make any sense to me I don’t know are they metric or what

    • could you please email me webster engine plans in english (inch)., . the measurements online don’t make any sense to me I don’t know are they metric or what

      • I just discovered, after all these years, that the plans are in metric dimensions. I think Mr. Webster released his plans in both US and metric dimensions and I’ve – only – got the metric ones. One of the dimensions is “53.98” and that converts to 2.25 inches.

        I just searched the net and the only plans I could find for this engine are the metric ones.

        • years ago I built the webster engine from Joe’s plans in u.s. (inch), measurements. I don’t have them anymore so I now use an 8 inch caliper to convert metric to inch measurements.. mine has inch, metric ,and fractions. .I’m attempting to make my second webster engine now .

  1. Hi: The PDF file download goes into a loop and the engine plans will not download.

    Can you e-mail a set of DWG ACAD drawings to me in stead.
    Don Doerner

  2. Don,

    You’ll have to request a set of DWG plans from Joe Webster. His email is

    “webster_engines -at-”

    BTW, I tried downloading the PDF version and didn’t have a problem.


  3. Hello my name is Alonzo i would like to know if anyone could tell me anyplace to get copies of plans to put together a scale model Associate hit and miss gas engine.? Thank you for any help.


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