Strange Noise - Need Help to ID

[Pilotdave]

Recently we have been hearing a strange noise while driving in our '31 Roadster. Here are the clues:

1. Sounds like a piece of sheet metal dragging/bouncing on pavement or rotating and hitting something.
2. Seems linked to car moving - haven't heard it while car is stopped with engine running.
3. Appears to be speed (car or engine) related.
4. Intermittent
5. Sounds as though it's coming from front of car.
6. There are no pieces of metal (loose or otherwise) hanging under the car that could hit the road. Muffler is firmly in place.
7. All brake rods are properly attached and equipped with anti-rattler springs.
8. Fan is two-blade aluminum and doesn't hit anything when rotated.
9. Nothing lurking inside hubcaps.
10. Starter motor and alternator are firmly in place.
11. Throw-out bearing has been greased - along with all other lube points.

I haven't yet pulled the wheel hubs to look for anything flaky inside...mostly as this noise is louder than I'd expect from, say, a broken spring inside there. But this maybe sloppy thinking!

Would appreciate any suggestions!

Thanks much.
Dave

[Clem Clement]

Splash pan edge rubbing something. Hit them with a rubber hammer

[Bill G]

This is probably not your issue, but I recently had one that drove me nuts.



Driving around and as I accelerate there was a definite bang coming from the rear of the car. Decelerating and braking, the same noise, but slightly different. I was concerned that maybe a brake backing plate had come loose and was making the noise. Nope.


Checked everything. Then, I remember I had the back seat out (Tudor). I lifted the back seat cushion to find that I had left a 3/8 inch wrench extension in the pan under the back seat.


That will do it every time. Kind of like the doctor suturing the sponge in the patient. (Not quite as bad of consequences, though)

[Pilotdave]

Thanks, Clem and Bill. I will check the splash pans. And it COULD possible be a part of a tool left where it definitely should not have been. Also worth checking.

Other suggestions are welcome!

Dave

[1931 flamingo]

Ck the radiator support rods (F/wall to radiator) for being loose.
Paul in CT


Hope you're feeling OK, I still include you in my prayers every night. Just noticed Grafton, my daughter's in Hopedale!!

[Pilotdave]

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Thanks, Paul. Yep - good idea. The support rods are snug. Yesterday this car went on a 50 mile ride - 25 out and 25 back. No noise until into the return. And then it went away.

Hopedale is just down the road a piece - I buy parts for my old tractors there.....and run tour routes through parts of that town. And I'm feeling fine - thanks!

Dave

[heneste]

If you have a stone guard in place, they sometimes build up a vibration that will rattle a bit and gets amplified through the front sheet metal. (Same idea as the splash pans)
Is your horn cover tight in place? I know my car has a bit of a worn hole where the cover screw goes so, although the cover is attached to the horn, there is some slight play in the cover and I get the odd rattle from time to time at speed.
Have you checked the universal joint lately for grease? If it is starting to dry up you may get some additional noise and/or vibration occurring.
Best of luck tracking down this gremlin.

[Pilotdave]

Thanks for the ideas, heneste. The U-joint space was stuffed full of fresh grease recently when I greased everything in sight. No stone guard, but a good idea! I'll double check the horn cover.

Dave

[Bill G]

Also, maybe not your problem, but I had another noise yesterday. I went to a car show 30 miles away. When I was almost home there arose such a clatter. I sprang from the car to see what was the matter.

Last fall I put a sheet metal muffler heat shield over the muffler. I bought it from one of the suppliers. It's held to the muffler with two U bolts; One front and one back. One of the sheet metal brackets broke off and the sheet metal was flapping by just the front mount. Easy fix. Drove it home and when it cooled, I took it off. No more noise. Well, the car makes lots of other noises, but that one is now gone.

[TerryH]

If the engine pan tabs break off, it will contact the engine while loose, and make a heck of a racket at speed. This happens twice on my car, and Tom Endy solved the problem for me.

[jhowes]

Terry, I am facing that problem, what did Tom Endy do to solve the problem? Removing them seems like the only solution.

[old31]

Originally Posted by Magicbox51

This is probably not your issue, but I recently had one that drove me nuts.



Driving around and as I accelerate there was a definite bang coming from the rear of the car. Decelerating and braking, the same noise, but slightly different. I was concerned that maybe a brake backing plate had come loose and was making the noise. Nope.


Checked everything. Then, I remember I had the back seat out (Tudor). I lifted the back seat cushion to find that I had left a 3/8 inch wrench extension in the pan under the back seat.

That will do it every time. Kind of like the doctor suturing the sponge in the patient. (Not quite as bad of consequences, though)

Well, don't feel bad.

I went to a show about 15 miles from my house. I am sitting down and a guy comes up to me and said, let me guess. The last thing you worked on was the brakes. I said ya, how do you know that. He said follow me. He took me to the front and said look. I had left my 7/16 boxed end wrench hanging from the adjuster. A senior moment.

[Pilotdave]

Thanks for all the suggestions. And the stories! Sadly, I'm still looking for the culprit!

Dave

[Jacksonlll]

Reach up under the gas tank where the big clamps are that mounts the tank to the car. One of mine came loose and made a terrible noise rattling around, still hanging from the flange. I thought it was in my hood somewhere. Took a long time to find it. Jack

[Tom Wesenberg]

Check the radiator rod brackets that are riveted to the firewall for loose rivets.

[daveymc29]

I had a noise than seemed to come and go. Not really speed related but the car had to be moving. Scratched all the hair off the top of my head bone trying to figure it out. Then one day I was convinced my distributor was giving me fits and I went looking for my spare. You guessed it, under the front seat and rolling merrily about, having come out of the gunny sack that is usually wrapped around it.

[Jacksonlll]

Those hood prop brackets can cause a noise problem. It took a rubber band to stop my noise.

[heneste]

Could it be a loose hubcap rattling about? Would be nice if it's just a little play in one of those.