Any ideas for building a 'car rattler'?

[alchemysa]

I absolutely hate rattles and squeaks in cars. They drive me crazy. My wife says "'Just don't listen" but thats impossible for me (and most men I think). For the last 2 days (and not for the first time) I've had the back of the wagon stripped out, looking for squeaks and rattles, but **** they are hard to find when the car is standing still!

So, for years I've been thinking about building some kind of electric gadget that can rattle the car while I clamber around inside.

I think something that can be driven on, one wheel at a time, would be good. And it probably needs variable speed and amplitude, although variable speed alone would probably do the trick if the amplitude is sufficent. I'm thinking at least 1'' of movement is needed but maybe it needs more. And most importantly of all it needs to be some thing that can be built pretty cheaply from 'junk' thats lying around or can be cheaply sourced.

Have you guys ever thought about this? I've had a few rough ideas but I reckon I'm missing something. I suspect there's already some machine, or part of a machine, out there thats just right for adapting for this? For example, I reckon a dirt compactor has probably the got the makings of a car rattler but they are not something you find in junk yards.

Any thoughts or suggestions for this project.

 

[Jim Shooz]

Let your wife drive while you climb around inside looking.

 

[alchemysa]

Let your wife drive while you climb around inside looking.

Already done that a few times. She never seems to be able to hit the bumps like I do.

 

[Wild Bill the 2nd]

If you want variable amplitude and frequency that is adjustable on the fly then I imagine you'd build some monster speaker of sorts and then use a tone generator for the input. Would probably need a pretty big Amp too.

I believe this is how earthquake simulators and other laboratory shock and vibration equipment is made.

For practical purposes I'd think a mechanical apparatus would be easier and cheaper to build.

Have some sort of Cam under a plate. The Cam is driven by a motor. Plate is drilled in all 4 corners for posts. the post holds the vibrating plate between two Springs.

Also look up pneumatic vibratory motors. That may actually be the ticket. Just be careful what you click on when searching on this topic.

 

[SPYDERLK]

Polygonal "wheel" from multi plywood laminate.

 

[s219]

The car manufacturers have big "shaker tables" that do exactly this sort of thing. I suspect that without the ability to cover a wide range of frequency and amplitude, you'd never find most of the squeaks and rattles. You can buy smaller shaker tables (intended for lab use) that might be able to excite a single wheel enough to trigger some squeaks and rattles. Maybe if you see what the commercial models look like you could build one similar.

Thankfully, cars have gotten much better in this regard. I too am annoyed by squeaks and rattles in a new car. Older cars were much much worse, and I remember chasing down and fixing issues in a number of new cars back in the 80s. Can't say I have had issues with any recent new cars or trucks though.

 

[Sysop]

Someone driving while using a mechanic's stethoscope is the best option. Climbing around the car changes the weight distribution across the suspension and will effect whether noises are created or dampened. You want the weight distribution of the vehicle as close to what it typically sees as possible.

 

[alchemysa]

If you want variable amplitude and frequency that is adjustable on the fly then.

For practical purposes I'd think a mechanical apparatus would be easier and cheaper to build.

Have some sort of Cam under a plate. The Cam is driven by a motor.

Variable speed on the fly is essential, but don't need variable amplitude on the fly. That would get very complicated.

'Some sort of Cam'. I like it! How about using a head off an old overhead cam engine? (An old V6 head for example). A cam is strong enough to carry one corner of a car and its already mounted in the head with bearings and everything. Beautiful. The cam could be belt driven using a V belt and pulley to replace the original timing belt sprocket. A plate, hinged at one end could be resting on top of the cam shaft, maybe with thick nylon runners bolted to the underside of the plate so its only sitting on 2 matching cams at once.

A problem could be that the 'rattler' makes more racket than the rattles, but this sounds like a direction worth considering.

 

[KiotiKowboy]

Best way I've found to get rid of rattles is - Don't buy a Dodge.

 

[alchemysa]

Someone driving while using a mechanic's stethoscope is the best option. Climbing around the car changes the weight distribution across the suspension and will effect whether noises are created or dampened. You want the weight distribution of the vehicle as close to what it typically sees as possible.

The trouble with rattles and squeaks is that they are so erratic. They don't came and go on cue. They never appear when you want them too. They may only happen once every couple of minutes. You could cover miles and miles and achieve nothing.

Anyway, its illegal to clamber around in a moving car over here.

I think you need to have a continuous vibration to get the rattles to 'emerge'. Of course you won't get them all.