Noisy fuel tank baffle

DanEC · #1 (**permalink**) 01-02-2015, 04:04 PM

Curious question - I keep my ERA on roller dollies and push it into a corner of my garage. The baffle in the fuel tank has always made a lot of noise at the slightest movement of the car. When building the car I figured fuel in the tank would quiet it down - but I think fuel actually keeps the baffle rocking due to wave action and creates more noise. I can give the rear of the car a light sideways push on the rear tire and the fuel tank will clatter for some time - probably 5 or 6 seconds after I stop moving it. I'm not sure if I can hear it or not when driving. When the car is not warmed up hot, I hear something like a rattle from underneath at low speed but it seems to die out when the car is hot. I've yanked around and beat on everything possible with a mallet and can't find anything loose anywhere or duplicate any rattle except from the fuel tank. Even pulled the mufflers off and shook them around to check for a loose baffle.

Probably not many of your store your car on dollies and push it around much - but wondering if anyone had noticed a noisy fuel tank baffle? Probably will live with it - don't see much can be done to deal with it.

strictlypersonl · #2 (**permalink**) 01-03-2015, 03:57 AM

The later cars have nylon flaps rather than swinging gates. On your car, once the engine fires (even with under-car exhaust), you won't notice the noise. Also, the more fuel in the tank, the less clanking there is.

DanEC · #3 (**permalink**) 01-03-2015, 04:46 AM

Thanks for responding Bob - I probably haven't filled the tank too much over half way. And I hadn't been able to distinguish the noise for sure when driving but I do seem to have a little light rattle somewhere from outside when first setting out - guess I will keep looking. Maybe it's a brrake pad.

davids2toys · #4 (**permalink**) 01-03-2015, 06:26 AM

I thought that was the sending unit. I just went out and shook the car side to side and got the noise with very close to a full tank. My car is #698/2003, much older than yours, so the design inside the tank may be totally different than your new ERA.
Next time(soon I hope) I put the car in on the lift, I will try and track down that noise better

ZOERA-SC7XX · #5 (**permalink**) 01-03-2015, 06:38 AM

I hear the flapping every now and then after I put my car away in the garage and shut it off. If all else is quiet I can hear the baffle rocking for a bit, but have never heard it when running & driving. I have no problem with it.

DonC · #6 (**permalink**) 01-03-2015, 06:43 AM

I usually fill the tank on 684 at the end of a run before I get home but, when I don't, I can hear the flappers clicking for about 5 seconds in the sudden silence when I turn the engine off.
DonC

patrickt · #7 (**permalink**) 01-03-2015, 07:01 AM

I just went out and grasped both roll bars from behind and shoved hard twice. There's about half a tank of gas in her right now and the trap doors clapped clearly, and evenly (like a metronome), for 30 seconds (as timed by my watch). If the engine is running, I never hear it.

Boat3 · #8 (**permalink**) 01-03-2015, 07:39 AM

DanEC, my tank baffles make noise also, just like as the other replies have mentioned, BUT I too get a metallic rattle at idle/low speed when the car is cold, and it's more pronounced on the driver's side and towards the front of the car. Once everything gets up to temp it goes away. I thought it was exhaust (I have stainless side pipes, not under car as yours), but I could find nothing loose, nor can I find anything else.

Larry

DanEC · #9 (**permalink**) 01-03-2015, 07:50 AM

Quote:

Originally Posted by Boat3

DanEC, my tank baffles make noise also, just like as the other replies have mentioned, BUT I too get a metallic rattle at idle/low speed when the car is cold, and it's more pronounced on the driver's side and towards the front of the car. Once everything gets up to temp it goes away. I thought it was exhaust (I have stainless side pipes, not under car as yours), but I could find nothing loose, nor can I find anything else.

Larry

Larry, that sounds similar to mine. Not a big deal - with my hearing I probably would be oblivious to it with sidepipes. A couple more years and I probably won't be able to hear it anyway.

It could be my exhaust somehow. It's strapped very rigidly to the car although I tried to fabricate mounts with rubber isolation as best I could. It can't bang against anything but it could be some sort of tinny resonance in the exhasut.

Patrick - I under-reported how long mine will clank so as not to appear to be embellishing - but it probably will go on for about that long on my car too.

Thanks.

Boat3 · #10 (**permalink**) 01-03-2015, 08:23 AM

Maybe someone else will chime if they've found/experienced a similar noise? I was wondering if it could be valve train noise that's channelling through the headers/exhaust?

patrickt · #11 (**permalink**) 01-03-2015, 08:55 AM

Quote:

Originally Posted by Boat3

Maybe someone else will chime if they've found/experienced a similar noise? I was wondering if it could be valve train noise that's channelling through the headers/exhaust?

This will allow you to pinpoint the source of your noise. It's an absolute magic tool and I've used it for almost 40 years. It will find the origin of your noise.

DanEC · #12 (**permalink**) 01-03-2015, 09:42 AM

I have one of those and never have had any luck with it. Being mettalic, touch it anywhere to the engine and it sounds like a sewing machine on steroids. I might be able to isolate a rod knock with it if I were lucky. Maybe there are better quality ones available. I think a lenght of heater hose works better.