pblancha

I just replaced the complete exhaust system with a new stock reproduction on my 1964 327/300. Sounds great, but it has a weird metallic sound coming from within the pipes. There is nothing in the pipes and it does not appear to be a vibration noise as nothing is hitting anything. The muffler shop that installed it thinks it could be caused by a misfire, although it did not make that noise with the old system. Any thoughts on what it could be?

pop23235

Internal baffle in the muffler?

pblancha

Maybe, but the noise seems to be coming more toward the front in the area of the head pipes

gsholz

Are you still running the heat riser valve on the passenger side? May be the source of the noise.

Another potential area is where the pipes go through the chassis cross member. If not adjusted correctly the pipes can hit the cross member

DansYellow66

Did they install the sleeves and leave out the donuts at the manifold connections? I have a BB and I'm assuming the SB headpipes install the same way.

pblancha

No heat riser - installed the spacer in its place. As far as I know the sleeve on the left side and both donuts installed - didn't watch the entire install. No exhaust leaks though

Daren67

Do you have heat shields? If so that could be problem. Mine were 1 inch too far forward and hit and made noise

MikeM

Can I assume you know the sleeve goes on both sides?

pblancha

Hmm - I know the old system did not have one on the right side and if both came with my system than I would think the muffler shop would have installed both. That said, I better check. Thanks

pop23235

What sleeve?

DansYellow66

I won't pretend to know a lot about this subject - but on my BB there is a short pipe sleeve that runs through the donut seal and gets clamped in place when the flange is tightened up. My understanding is it positions the donut and protects the donut seal from direct exhaust gas/heat.

MikeM

It protects the seal from being crushed when you tighten the pipes to the manifold. No sleeve and you'll find the pipe loose if you check it. Tighten it up, run awhile and it'll be loose again.

If you use the metal (Ford) doughnuts, you don't have to use the sleeves.

That said, I don't know if that's where you noise is coming from or not.

https://cdn3.volusion.com/ekutc.vrls...jpg?1495527359

pop23235

Maybe I should start another thread with apologies to the OP, but my 64 with 2 1/2" doesn't have a sleeve, (327/365). The doughnut slides over the pipe which has a cone shaped flange that the loose flange presses against. The doughnut is pressed by the cone of the pipe, the cone in the manifold and the od of the pipe on the id of the doughnut. Doughnut is pressed on three sides, can't go anywhere. Still don't see a sleeve, nor any place it could fit. These are OEM pipes.

leif.anderson93

these...
http://www.parts123.com/parts123/yb....5Z5Z50000370a#

MikeM

Please follow the link in post #12 for the correct OEM pats in this assembly and don't try to confuse people.

pop23235

Mike, that pic is different from my 2 1/2” pipes. The doughnut is too low. It fits on the inside of the exhaust pipe, not outside. My flange is either cast or forged, not stamped. The flange presses against the exhaust pipe, not the seal ring. Plus my pipes extend through the doughnut. The end of the pipe is obviously two parts welded. Maybe that sleeve is for aftermarket pipes?

MikeM

The sketch I posted is OEM design.

On closer examination, the sketch is a little misleading as it shows two different sleeve diameters. But it does show a sleeve on the right side.

Put the sleeve in the pipe, slide the doughnut over it and push it up against the heat riser.

Kerrmudgeon

Loose baffle inside one of the hew mufflers perhaps?

MikeM

Here's a better sketch.

pop23235

Mike, is this only the heat riser side? My pipes were "over the counter" GM and there is already a "continuation" or projection of the pipe internally to the tapered flange. The doughnut fits nicely into the triangular cross section void between the internal pipe extension and the outer pipe flange. With the doughnut in place the internal extension extends above the ID of the doughnut. If I were to try to install any other sleeve, it would interfere with the heat riser valve.

This picture is much more accurate/clearer. Maybe the GM pipes have the sleeve welded in already? The part of my pipe that would be equivalent to the sleeve is part of the pipe end. Don't know if the internal part is welded in after the end of the pipe was flanged, or the flange is welded below the end of the straight pipe, but nothing shows on the outside. As I recall, the bottom of the manifold or heat riser is tapered for the doughnut. The pipe extends upward such that little if any exhaust gas will touch the doughnut.