Vibration gas tank

[willyhuaz]

THE BAFFLES IN THE GAS TANK ON MY 29 MODEL ROADSTER ARE LOOSE.
THEY RATTLE AND VIBRATE AT CERTAIN rpm AND SPEED. IS THERE ANYWAY TO FIX THIS PROBLEM WITH CUTTING THE TANK OPEN?
THANKS
WILLY.

[SeaSlugs]

are you 100% sure without a doubt thats it? sure its not the choke rod buzzing or instrument panel vibrating or spedo cable rubbing on the tank?

[willyhuaz]

I'm 95% sure it is the baffles, but I never checked the speedo cable. Thanks for the suggestion. Starting out, it will start vibrating and quit when I get to 30 MPH. I'll chek out the cable.

[KGBnut]

I had a similar rattle that was driving me crazy. I was convinced it was in the tank. It turns out it was the ears on the radiator where the support rods connect. The rods would then shake and transfer that vibration to the firewall near the gas tank and that is where I heard the buzz.

[SeaSlugs]

Originally Posted by KGBnut

I had a similar rattle that was driving me crazy. I was convinced it was in the tank. It turns out it was the ears on the radiator where the support rods connect. The rods would then shake and transfer that vibration to the firewall near the gas tank and that is where I heard the buzz.

Yea check everything, would hate for you to go thru the trouble of pulling the gastank, cutting it open, welding up stuff that MAY be it, then welding it closed and repainting and reinstalling it to find out its a 1/2" nut that needed turned 1/4 turned on a support rod haha get a few people to look things over.

Ive heard brake return springs/antirattlers make a hell of a noise if they are a hair loose on the rods.

also make sure your throttle linkage isnt rubbing the lower firewall or your hood sides arent buzzing against the cowl.

Also pay attention to the fuel level - could be your float /float rod rubbing something

does it only buzz when your moving or is it a certian RPM you can move the throttle lever down in neutral and start pushing or pulling things to pinpoint the sound?

[OL JENNY]

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I have a similar problem with a vibration that only occurs when my tank is near 1/2 full or less. If the top half of my gas tank is full, the loud vibration does not happen. I have now discovered that a 4 - 5 inch area of the windshield frame in front of the driver is rubbing on the gas tank. When my tank is full it settles almost 1/8 inch lower. I have filed the windshield frame so it does not rub and we will see. I had a body shop remove my tank last winter for work and I am now thinking they did not get it seated well. I don't know exactly how to pull it down more. Check for this problem also.

[Tom Endy]

If you have a brass gas gauge float installed it could be rattling against the inside of the tank.

Tom Endy

[KGBnut]

I ultimately found that problem with my radiator by walking all around the car and thumping on everything I could think of with the heel of my hand. It took quite a while, but eventually the thump returned a rattle and I traced it down.

[goodoldvic]

Excellent diagnostic procedure KGBnut

[BILL WILLIAMSON]

RATTLES will drive you NUTS! It took me 4 days just to discover the windshield opening KNOB wuz loose.
Took me 3 weeks to find that the wood piece, behind my R/H 1/4 window was loose. Took off the trim piece & a little POOOF of insulating foam fixed it!
Bill Quiet

[willyhuaz]

Thanks for the good ideas. The vibration occurs when the engine is revved to around 300-900 RPM, even sitting in the shop. I checked the speedo position, it is not the culprit. But, I will check the things you all said to try, maybe I'll find it. It seems to echo on the left side of the firewall when I'm inside of the car.
Thanks again.

[davidlee1313]

Could it be that the flame baffle is loose at the neck?

[Wm J.]

I found my problem was the repro hood prop kit with the fold out ends. They attach to the radiator rods and the pivot bolt is loose that allows the ends to be folded out to hold the hood in the open position. If you have these things on your car either tighten the bolts or tape the folding end back with black tape.

Wm J.

[SeaSlugs]

Originally Posted by willyhuaz

Thanks for the good ideas. The vibration occurs when the engine is revved to around 300-900 RPM, even sitting in the shop. I checked the speedo position, it is not the culprit. But, I will check the things you all said to try, maybe I'll find it. It seems to echo on the left side of the firewall when I'm inside of the car.
Thanks again.

should be easy then - set the throttle or you or someone else sit in the car and keep it ratteling then like me and others have said start slapping and pushing/pulling everything and try to track it down.

sometimes when things sound like they are coming from somewhere they are actually the exact opposite.

[1crosscut]

Get someone with young ears to help.