MTFCA Forum

On the last few cold starts I’ve heard a strange metallic tinny sound that eventually goes away in about two or three minutes. Always thinking the worst I thought it was something loose in the transmission imagining some piece that fell off and is kicking around in there. I lubricated the fan thinking this might be the problem; nope. I changed the oil thinking I might find something in the oil ... nope.

Then the next time it happened I thought it came from underneath so I quickly climbed under and it sounded strong around the muffler and pipe assembly. I thought that maybe when I changed the manifold gaskets recently I may have put the exhaust pipe back in a way that caused a rattle. So, I loosened up the pack nut and tightened it while wiggling the pipe to seat it. It still didn’t make much difference. So, I’m still wondering what’s making the sound ... but at least it goes away once the engine’s hot. Could be because I’m using a cast iron end muffler and the pipe is simply pushed into the inlet hole. It’s probably something really simple like once the pipe gets hot it fits differently. I was once told that when you hear hoof steps behind you ... think horse ... not zebra. I’ll figure it out.

The carburetor heat pipe has fooled me before. You might check where it is bolted to the manifold clamp. You may recall I pulled the oil pan inspection cover looking for a rattle before I discovered the former.
Rich

Sorry, a double post, and edit.

I’m not using a heat pipe on my carburetor.

Exhaust leak? As the engine warms up and metals expand the leak seals. Just a thought.

This is another long shot, but because your car was fine before the U and J carburetor change, try checking the rod from the bell crank to the carb. It is at a different angle now and may need some tightening at the carb or bell crank. When car is warm it is in a different position, so no noise.

Make sure the bendix cover is not coming loose! (....altho' that should also cause an oil leak,..???)

I had a crankshaft pulley that was loose and made a noise that took awhile to find.

I've found through the past two years, my Model T runs better and quieter than ever. Meanwhile, the audiologist claims I have increased hearing loss. I refuse to believe there's any connection hear (!) Bad noises get worse and louder . . . inconsequential noises that go away, well, What ?? Me worry ??

Loose through bolt allowing baffles to rattle?

Well ... not the throttle rod, crank pulley, fan pulley, bendix cover. The rod running through the muffler sounds plausible.

Have to do a dry plate photography shooting workshop in Letchworth Park (Grand Canyon of the East) starting tomorrow. So I’ll keep thinking about it while I’m out of contact with the civilized world and work on it this coming weekend when I get back.

Can you tell if it's front or rear or middle ?
Your eat on a long screwdriver handle works like a stethoscope, you can move it around and see if you can pick up the area.

Could be a "loose nut behind the wheel" !