PaleCivic repairs & upgrades

[PaleMelanesian]

Over the break I replaced my old cracked exhaust manifold. Thanks to Honda's one-piece design, that meant replacing the catalytic converter as well. The casting was a flawed design and this is a common failure point. Junkyard cars usually have the cracked manifold as well. I went with the $167 Dorman aftermarket replacement instead of OEM for lower price and (hopefully) a better design.

The old cracked manifold. O2 sensor already removed. Heat shield missing when I bought the car. Overnight I soaked everything in Liquid Wrench.


Trouble! This nut at the bottom end of the catalytic converter wouldn't come loose. Unsurprising, really, after 16 years.


So I unhooked the next joint about 2 feet downstream. This came loose much easier as I replaced the following pipe only 5 years ago. It was a hassle to remove the L-shaped mani-cat-pipe combo - I loosened the front engine splash shield to drop it out the bottom. Once out on the ground, I hammered a socket onto the stuck nut and was able to remove it. Getting good leverage was much easier that way.


The new manifold. Everything fit pretty well except for one bracket. A couple spacer washers and that was fine. Both O2 sensors salvaged and reused. Notice that this is a 2-piece design with a bolted joint just below the manifold.


All finished, this time WITH a heat shield. Now it's again a CleanMPG machine, instead of just MPG. Performance is no different that I can tell, just a tiny bit less engine noise that only I (the daily driver) would notice.

[PaleMelanesian]

In the engine bay shot above, notice the tiny battery in the top left corner. It's barely big enough for "normal" driving, and wholly inadequate for my FAS-heavy routine. I have a trickle charger installed in the space under the air intake. The power cord comes out behind the license plate so I can easily plug and unplug it every day.

[PaleMelanesian]

Also, you can see my upper and lower grille blocks in the last two images. Plexiglass for the upper and foam exercise mat for the lower. The foam is cut to size and press-fit into place. It's looking a little rough, but that's after 2+ years of life on the road.

[EdwinTheMagnificent]

How did you discover that it was cracked ? Did the crack affect performance ?
I'm curious because we have two of these cars in the family (97 Civic DX , 97 Civic LX).

[Mr. Pancake]

Originally Posted by EdwinTheMagnificent

How did you discover that it was cracked ? Did the crack affect performance ?
I'm curious because we have two of these cars in the family (97 Civic DX , 97 Civic LX).

More than likely they are cracked. The manifold on my wife's 98 EX was cracked as well.

[PaleMelanesian]

The crack is clearly visible when you pop the hood. It started small a couple years ago, but it's been growing. In the last couple months saw some black deposits around the back side, facing the engine block. (you can see some of this in the top photo) Also, this winter it started sounding a little bit more diesel-like on cold starts. It was minor, only something I would notice as the daily driver.

It's worth your while to pull the heat shield and check - it's only two bolts.

It did not affect performance at all. I was hoping the new unit with heat shield would make for faster warmup, but it didn't. I pulled in to work this morning after 13 miles with 177F - not quite full temp. I think a new thermostat is in order.

[EdwinTheMagnificent]

Thanks. I will check the cars next time I see my daughters.

[Harold]

I'm wondering if that heat shield is part of the reason they crack? H

[PaleMelanesian]

General opinion at Honda-Tech is that it's a poor casting, too thin at that high stress point. Drilling a hole for the O2 sensor makes it even weaker. There are numerous threads over there about this same problem.

[Right Lane Cruiser]

Nice work, Andrew! I'm glad you've got that repair out of the way so you can rest just a tiny bit easier knowing at least that component isn't going to fail spectacularly.