Algodoo

So I've been trying to make a throttable spring engine, so far it worked well, until I actually tested it on a map. When you accelerate the engine
close to the limit, when it hits a bump the pistons will come out from the engine flying

I tried putting more mass on the cylinders and the pistons, putting less spring constant, but nothing works, it either plainly doesn't work
or it reduces the power of the engine by a lot

controls to operate the van:

1-5 (not numpad): gears
Q: Neutral
Left and right arrow: Throttle
Down arrow: brakes
Enter: start/stop engine

just accelerate the van (not full throttle, half a throttle will work

If you zoom out you can get a version of the engine (with no controls) that you can inspect easily

Thanks in advance