FWD Muffler Clamp

[Klattu1929]

I have seen a few posts on exhaust clamps ahead of the muffler, but haven't come across any actually being installed. Has anyone tried it? If so got any pictures, and or feedback. I've been giving it some thought, but am on the fence so to speak. My manifold is fine and gland rings are installed. I have a manifold that does not have the extra meat to help against drooping(as some have suggested). Lots of folks are purest, and it's a good thing, but other folks have been tinkering , changing, etc. etc. since the A was introduced. Both are kind of part of the A story I think. Lots of wisdom out there, I am always trying to learn more. I just ordered a new Aries exhaust, so thought I would ask about the fwd clamp business, Thanx.

[J Franklin]

I can't see it doing much.

[Joe K]

The connection between the exhaust pipe and the manifold is a "flare" - some may even find it is a "spherical" connection.

"Mating" the flare to the taper/ball is essential. I have had the exhaust pipe out and "tinkered" with the connection repeatedly trying to improve - even to the point of using a black magic marker as a sort of "contact dye" to tell where contact between the two parts is made or weak.

Joining together SHOULD be metal to metal, and held together by the clamp halves. I have examined MANY clamps of my ownership and found that original clamps seem to have the most "meat" and encircle the union connection better.

IIRC, the clamp is placed with the "long side" down next to the pipe. This is where the original clamps seem at their best.

The repop clamps seem to have less meat in this area.

After I got the match as close as the hammer/flare can be made, the connection ALWAYS seems to improve with the application of common "pipe-joint" compound, the stuff that comes in a dispenser bottle with the paint applicator on the screw lid. The heat sets the compound and solidifies it - and fills any gaps/leaks. There usually is not much leakage by this point if your previous work was solid.

Many have advocated metal "inserts" and/or "gaskets" available from the Model A sources for this application. They may work and improve the seal with a poor mechanical connection, but also may be a place for vibration to loosen the connection. I have never had the need to use them.

Hope this helps. An exhaust leak can be most disheartening.

And the exhaust manifold of my ownership that I couldn't find the leak comes to mind. Using a pump oiler and flooding the surface of the manifold revealed "bubbles" coming from what I thought was solid casting. Dropping the removed manifold on the pavement, it broke into at least five pieces - and from the appearance of the now sundered cracks, it had been cracked for some time.

Joe K

[CT Jack]

I am not a believer of exhaust manifold droop on an original type exhaust system if it is properly installed and maintained. This requires both the intake and exhaust manifolds be machined flat, installing a set of gland rings with the proper depth, and using a A9433-B copper gasket. The reason for using an A9433-B gasket is that the 4 holes in the gasket align eactly with the manifold mounting studs. All other gaskets use slotted alignment holes which can be more difficult to align. After installing the manifold it must torqued to 50#-ft. Retorquing should be done each time the head is retorqued. Also the muffler tailpipe should be properly mounted using the correct clamp and tightened correctly.

[nkaminar]

Cast iron grows when heated. The asymmetric shape of the exhaust manifold at the rear will force it to droop down if not restrained.

I torque my manifold bolts to 55 foot-pounds and then retorque after the first heat and then after 100 and 500 miles. I have the Weber downdraft manifold which is not bolted to the exhaust manifold. If you have the stock configuration, then make absolutely sure that the intake and exhaust manifolds are co planer and flat. If not sure then use a lower torque, like 25 or 30 foot-pounds, but still retorque as above.

[Hitman]

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Originally Posted by nkaminar

Cast iron grows when heated. The asymmetric shape of the exhaust manifold at the rear will force it to droop down if not restrained.

I torque my manifold bolts to 55 foot-pounds and then retorque after the first heat and then after 100 and 500 miles. I have the Weber downdraft manifold which is not bolted to the exhaust manifold. If you have the stock configuration, then make absolutely sure that the intake and exhaust manifolds are co planer and flat. If not sure then use a lower torque, like 25 or 30 foot-pounds, but still retorque as above.

Throw out the torque wrench for the manifold nuts. Tighten to feel, the gaskets don’t compress or squish, making it easy to over tighten breaking studs or manifold ears. The manifolds and block are a machined surface, so they just need a gasket and tightening.

The original manifolds bolt together for heat transfer into the intake manifold. If they are not machined flat on the manifold surface, you’ll risk breaking a manifold ear, exhaust leak or intake/vacuum leak since you can ensure the manifold is properly seated. A lighter torque will not solve the issue.

Set it up properly and you’ll have no issues.

[Synchro909]

This is not for the purist but I have taken to installing a reasonably strong but short spring between the engine mount and a hose clip mounted just in front of the muffler. It means that there is no eight from the exhaust hanging on the back of the manifold. That takes care of the weight causing the manifold to sag, the other reason it does is the rear clamp being too tight. If that is the case, as the exhaust gets hot and expands, it puts forward pressure on the rear of the manifold. I make sure the "clamp" is not clamped tight.
As for the manifold-exhaust clamp, I have never seen one either repro or original that hasn't needed work. The new ones with a thread in one half make things much easier but still, there is grinding to do if you want to have a working clutch. Poor design, IMO.

[Tom F OHIO]

We worked and worked on putting the muffler to the exhaust manifold. It leaks really bad no matter what we do. Held it on with a jack and by hand and still no luck. Even used a new flange clamp. We took the muffler completely out and noticed the flange part doesn't look very good. Is there any way to make it a better flange at home or do we need to take it to a muffler shop and have them try to make a better flange. Thanks.....

[mhsprecher]

I had a problem with my exhaust pipe disconnecting. Turns out it was an old repro without much of a flange. I took it to a muffler shop where they made the flange bigger. Problem solved and no trouble since.

[Bruce of MN]

What did they need, other than the pipe/muffler?