Tuesday, March 14, 2023

Kees Bijker's 3D printed V4

 Kornelis Bijker from The Netherlands is building a 3D printed version of Dad's V4 engine.  Here's his latest update:


"Hello Allen,

It is quite the trip I have to say. I think I have 95%+ of all the parts modeled by now, and started modifying the fits, fasteners and certain details for 3d printing.

Things like the con rods I cannot print in one piece, so I had to modify them to have a bearing cap, a very small bearing cap. The miniature bearings are 2.5 mm wide so the bolts holding them on will be just M1.4, the tiniest I have ever used.

Most of the original designs I try to keep, but some parts are simply to difficult to print like that.

The guts of the engine will have all working mechanics, like crank, pistons, cams and timing gears, lifters and moving pulleys.

But internals of pumps and ignition will not have moving mechanics. Simply too small and too detailed for FDM printing to work well. And in a plastic model without petrol combustion, I do not need cooling or oil anyway.

Still not sure where I will build in the electrical motor. If not inside the crank case I might have to "invent" some fictional starter motor. Maybe a bell-house with a large gear instead of the flywheel. Not decided yet.

But as of now the fasteners have been modified to metric, so have most of the bearings. They are easier to find here then the ANSI style and imperial bearings.

I also have started printing things, mostly as a test to help decide tolerances and such.

I was quite happy that the fan shroud printed as well as it did. Also happy how the radiator insert came out, you can actually see through it.

Some things still to do are the throttle linkages, and yes the distributor will advance as well. I also will attempt to connect the speed potentiometer with the throttle link so that the engine will respond to the throttle. The sound is another story."


The first 4 images are the 3D software renditions of the V4, and the last three are actual 3D printed radiator parts.  Nice job Kees!  Looking forward to seeing this to completion!

March 21st Update:

Hi Allen,
Plodding on with modifications and printing and now also building.
The engine casing still needs cleaning up but I have started with the heads now. Some photos showing the tiny parts on a background of my notes for printing.
In view also the hand tools for this minuscule work. M2 hand-tap in a tap spinner and the M2 Allen key. Some photos show how the parts come off the printer. Looks a bit like an air-fix kit when they are all attached to each other. Right now printing the rocker arms and other small parts to complete the heads. I keep saying "other small parts", but to be honest all of it is small. Anyway next week I will be on holiday so no work on the engine for 2 weeks.
So far I have modified the valves to take a M3 bolt as a stem and the push rods with valve lifter to be made from a ground to shape M3 bolt as well. I am printing the clevis, as this is a really neat part that needs to look right.
Long way to go still.

Second email with more pictures and a section view of the engine to show the new valve and push-rod. setup. I have had to do away with the valve lifters and the ground down bolt head will take its place. The next email with the section view will show this

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