Faking a hose blowing in hot engine while at speed. . .

[Stephen Pruitt]

Hi all. . .

I'd like to get a shot from inside the passenger compartment of a radiator hose blowing onto a hot engine, with resulting water being blown up onto the windshield and smoke.

Any good ideas how to do that?

Thanks.

Stephen

 

[Bill Stengel]

This is a top-of-the-head guess, based on what is at play and what you're looking to recreate - a hot engine, a hot coolant-filled hose rupturing and spraying said coolant all over the engine bay. Coolant is boiled by the exhaust manifold, cylinder heads, block etc. Carefully rig a water balloon (start with one and maybe add more if you need a larger effect) above the exhaust manifold. Balloons could be on a makeshift shelf (think expanded metal or aluminum window screen or equiv) or in a "bag" made of aluminum window screen or equiv. The heat will degrade the latex, releasing the water onto the manifold where it boils off and makes some drama. You could also try filling some water balloons with coolant (if the coolant doesn't erode the latex) and using the same approach. I don't know if coolant makes a different kind of mess than water does when it boils off...

Again, just brainstorming here.

 

[Robert Hart]

You could rig the windscreen washer with a hose from the pump to spray on a hot exhaust manifold near the cylinder head. You would need to remove the weatherstrip under the rear of the bonnet ( hood in amer-english ) to allow steam and water to fly up. I doubt you would achieve the volume of sudden steam which is usually explosive. It is actually a steam flash explosion within the engine block once the containing pressure has been released.

There are effects experts who have long ago nailed this. My best guess would be to rig a CO2 fire extinguisher so that the outlet hose and spout eject a dense fog jet through the upper front grille or the gap between front body and bonnet/hood and trip the extinguisher remotely with a bowden cable ( lawnmower throttle cable ) or just a simple stout pull cord cut from green woven cord fishing line running out the back of the bonnet/hood to a passenger who yanks it on cue. The water you could achieve with a strong mix of instant coffee and a bit of milk in the windscreen washer system to replicate the rusty look.

You may find that the washer tank will siphon out empty if the washer hose outlet is lower than the tank. So before each fire, you may need to run the hose over a high point then down to the front and drain it after each firing so that it is full of air and cannot siphon. This will introduce a delay after firing before the water streams. That is not unauthentic. The water usually comes up after the initial blow. You should be able to avoid that grief by using a pressurised household garden sprayer instead and an operator firing it from within the cab. Be aware that spilling water onto a hot exhaust manifold may cause it to crack.

A well-maintained cooling system will throw green coolant. If you want this try some green cordial drink mix. It won't look anywhere near as sexy as turd-brown neglected engine rust-muddy water though. Run the washer line down to the front near one of the bonnet/hood corners out of sight, aim the end back towards the car so that the water stream moves in the windage over the bonnet/hood towards the driver's view. The blown water usually goes out the bottom with sometimes a bit of a splash from the original burst up on the windscreen and some water streaming back along the sides of the bonnet/hood.

If you are following up with a shot of the bonnet/hood raised, a dose of water on a hot engine should make enough steam for you. If that does not work, remotely fire the CO2 extinguisher momentarily before the bonnet/hood is raised and the heat from the engine and the hood opening should raise the vapour for you. For best effect, park the vehicle tail to wind so that the steam comes out frontwards.

Enjoy.

 

[Marc Wielage]

I think it would also depend on when the engine was made. If it were a 1950s or 1960s car, then I'd expect the engine hoses to look a lot more primitive than they would with a 2010 or 2016 car.

My advice would be to find a guy in your area who can do special effects and have him rig something up. It just takes money, and not necessarily a lot of it. I'm guessing a kid out of school would want a few hundred bucks, maybe a grand, provided he or she had some reasonable experience.

 

[Marcel M]

fog machine w/ hose fed under the hood ....