Working model of the Howell V-four engine

EDIT June 2025

In the step by step instructions I refer to instructions. Some of these are in the tabs with the screenshots but some ar in the other tabs such as "Tools needed and Techniques". If you see such a reference be sure to read in all the tabs for those notes, they are important!

UPDATE ON 9th FEB.

I seem to have forgotten to upload the radiator sides. They have now been added to the list.

The rocker arm bracket V2 is now also in the list.

Also the spur gear on the crankshaft was missing, also uploaded now.

I had initially uploaded the old version and the new version of the exhaust manifolds, namely V2 and V3, entirely by mistake. The V2 version has now been removed.

If you notice other mistakes, missing files or discrepancies, please let me know. Much appreciated if you do.

I designed this model from the original instruction drawings from Jerry Howell which I purchased. It took me over 8 months besides my day job.

This engine is almost exactly like the original except where I had to modify it to make parts 3d printable. Of course I had to change things since it is not a working engine as the original. Also I made see through holes in the model so you can see the internals at work.

First you do is unzip the zip file and read the instructions, please! This model is not easy, most parts are tiny and need special care for printing and handling during building.

There are 147 printed parts, 38 bearings, over 200 fasteners, some springs, dc motor with speed controller and a few assorted things from around the house.

In the zip file you find one spreadsheet with 23 tabs. Each tab is one section of information that you need. There are BOM's for printed parts, hardware such as bearings, fasteners and electrics and photos to show you the supports I recommend. Final sheet is a step by step guide to printing and building, Read it carefully and follow the instructions as closely as you can. I would print the BOM in order for you to mark where you got to and in which colour you want to print it.

I have built this engine at least 7 times now during my design, and I think my way is proven to work. If you find errors or a better way of doing things, please send photos and your comments to me and I promise I will have a look and try to help.

The hardware is metric and a small selection of miniature metric and imperial bearings. The motor and the speed controller are standard. So is the power supply. Most are readily available from Amazon or other internet portals.

Some items you will need to improvise. Such as a paperclip as a connection between throttle and distributor. Or the copper rod to act as the oil pickup line. But nothing is something very special I think. Metal clothes hangers are everywhere and all kind of the same, so are paperclips and elastic bands.

Finally have fun, be patient and tell us about your progress or downfalls. I promise I will look periodically at the comments to answer where needed.

Oh and before I forget, please look up the original at http://www.jerry-howell.com/V-Four.html. and http://www.model-engine-plans.com/

Also lots of photos and videos if you search for them. They will help you build this model, even though they are not exactly the same everywhere.

Good luck,

3dcase.