Replacing Car Exhaust System

New Muffler, Pipes And Clamps Replace Tin Cans And Rust

Copyright 2010 by Morris Rosenthal All Rights Reserved

The Omni Project

If It Jams Home

I don't see the point of showing step-by-step instructions for clamping together new pipes, so I'm going to focus on the kludges that kept the old exhaust system going for a decade. For starters, we have the famous tin can. The tin can in the picture to the right is wrapped over the pipe at a typical failure point, between the pipe welded to the catalytic converter (original 24 year old equipment) and the mid-pipe.There are two pipe clamps in the picture, the big rusty clams to the outside, which held an adapter in place. The adapter made up the distance left by the old end of the mid-pipe rusting off. When that adapter rusted through, I wrapped it with a tin can in 2007, muffler cement underneath, and put on the two aircraft clamps - most people call them hose clamps. They turned out to be excellent quality, never rusted. The repair lasted three years, not the three months some fools think you are luck to get with a tin can. The secret is using a thick walled tin can, cutting off the ends, and wrapping it around tightly over muffler cement.
To the left you see the rusted out muffler which failed at the seam, and motivated me to finally replace everything south of the catalytic converter for the first time in ten years or so. There's no intake pipe on the muffler because it rotted out completely last year and got wrapped in another tin can. That can barely aged at all in a year. The pipes themselves remained strong in the stretches where they weren't clamped, took a few minutes with a three pound sledge to flatten out the pipe at the curves so it could be bent into a single piece a few feet long. This particular system requires four pipe clamps: one between the catalytic pipe and the intermediate pipe, one for the clamp style hanger at the bend in the intermediate pipe, one between the intermediate pipe and the tail pipe, and one between the tail pipe and the muffler intake. The muffler is hung from the back with a bolt through the bracket mounted on the muffler.
To the right we have the old exhaust system and the new exhaust system. It's always a good idea to lay them side by side before installing to find out if the replacement pipes are an exact match. If they aren't, just bring them back and reorder. There are few car jobs more miserable than putting in a new exhaust system that won't fit because the pipes are two short or two long, and the auto parts stores don't like taking them back after they've been clamped and are useless. Which is a good time to point out that getting the right size clamps is critical to have a quiet exhaust system. When I picked these pipes up at AutoZone, the counter guy measured them with calipers and declared I needed 2" clamps. That didn't sound right, but he measured, so I took it all home, but when I went to put it together, they felt a little sloppy. I took them back and asked for 1-7/8" clamps, which they didn't have. So I went to NAPA, got the guy to look them up, they were 1-7/8" clamps, and they fit perfectly.
Unfortunately, with this brand new system and brand new clamps and pipes, I still needed a kludge. The reason is shown in the picture to the left. The original hanger was designed for a 1-7/8" clamp with one long leg, like an extra inch long. The long leg fits through the metal bushing in the rubber hanger (steel washers on both sides) and it suspends the pipe while clamping the intermediate pipe to the tail pipe. But the special clamp isn't an auto parts store stock item and I didn't want to wait for a special order, so I kept the bushing and the washers and wired it up with a coat hanger. Imagine, a brand new exhaust system with a coat hanger kludge. While the camera angle is a little deceptive here, I did hang it about a half inch too low. But my real ambition is to order up the special clamp sometime and just put it on right next to the clamp that's actually holding the pipes together.
So, with all the clamps installed and tightened, I fired up the engine and it roared like there was no muffler, no pipes, like I was running an open header. What had happened is my old kludge wiring up the flange on the exhaust manifold gooseneck had failed, so the steel donut dropped a little and the manifold was open to the world. The problem is I broke one of the manifold bolts like fifteen years ago doing some other job I don't remember and couldn't get the stud out. You'd think they would use a bolt, but it's a welded stud, or a bolt rust-welded in place. So I wired it, and during the current job, the weight of the catalytic must have stretched the wire, even though I tried to support it with a couple of bricks. After wasting a couple hours trying to come up with a better kludge, I just rewired it with a little galvanized wire and hopefully it will last another fifteen years.

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