fred_S

I have Z06 bi-mode mufflers on my car, and now the valves started rattling at certain rpm ranges.

Is there any way to adjust these, or do maintenance on them. I tried looking for an exploded view drawing to see how they are constructed, but so far no luck in finding a drawing.

Any tips of suggestions are highly appreciated

Fred

gotjuice?

It is probably not the valves rattling. The inside of the mufflers, Baffles start to come loose and rattle. Only thing to do is cut apart and reweld the loose baffle. It's common on high hp cars.

carlrx7

x2

I had to do the same thing. While I was in there I closed up the prefererated pipe.





The bottom inside wall is what cracks and breaks and rattles from the exhaust pulses.

-Carl

fred_S

I had the muffler mod done this Saturday, we had a good look at the sidewalls but didn't see anything out of the ordinary, tapping them didn't produce any rattles.

I will try tapping the outside with a hammer, if that doesn't reveal the source of the rattles it's another trip to the muffler shop

Thanks for the tip.

Fred

HOXXOH

Mine has the same rattle, but only around 1,000 RPM or less and only when the valves are closed.
Since the only time the valves are closed is when the wife is along, I haven't gotten too concerned with fixing the problem.

fred_S

Mine now seem to have the rattle only when the valves are closed, which for now is most of the time. I had the muffler mod done last Saturday, only to discover that after the mod the car is WAY to loud for me. Even with custom made ear protection the noise is deafening.

I live in the Netherlands were there are many people on bicycles, the slogan "Loud pipes saves lives" doesn't apply when they die of heart-attack from me accelerating

I will make another appointment with the muffler-shop to bring the noise down to acceptable levels, a good time to inspect the bottom inside wall for cracks, breaks and rattles and put in a few extra welds.

Fred

stroked383z28

My passenger side Z06 muffler rattles in the closed position. The problem on my car is with the vertical shaft that the actual butterly attaches to. It has too much slop that allows it to move up and down causing a metal on metal vibration. I can put my finger on it and apply downward pressure while the car is running and the noise goes away.

gotjuice?

Most valves will rattle, But you cannot hear it over the exhaust noise.

forg0tmypen

Did you ever fix this?

stroked383z28

I don't have a permanent solution yet, but in the mean time I've used a couple zip ties to help take up some of the slack in the butterfly assembly. This has stopped the rattle for now.

forg0tmypen

Thank you. This worked perfectly for me

chasboland

I have the exact same tin can rattle on mine. Does the zip tie interfere with the actuator's travel when it opens/closes? It looks to me like you can't have both the rattle gone and use m2w ?

stroked383z28

My m2w still works. The trick is to get the zip ties just barely tight enough to take up some of the slop. There will still be enough slack for the actuator to work.

forg0tmypen

Leave more slack than u need and when the valves close the zip tie will tighten automatically. That's what mine did. M2W still works. Zero rattle since!

chasboland

I have some .020 thick Teflon sheet at work that should make a nice u shaped thrust washer. It looks like it will take up about half the current vertical play/slop. Let you know if it is successful.

forg0tmypen

The problem is heat. Anything in and around the center shaft of the butterfly valve will get very hot.

chasboland

Well, it shouldn't get any hotter than the frying pans that are coated with ptfe (Teflon). Melting point is just north of 600 Degrees so it shouldn't be an issue.