Leak Finding
Again, remember that I hadn't made it through DEQ yet when I did this. With the muffler replaced, I shifted back to concerns which might interest the DEQ: the backfire. To find the exhaust leak, I simply started the engine with the hood up in my garage and listened. Nothing interesting... so I started feathering the throttle cable at the carb. With just a little rev, it was clear that the leak was coming from where the exhaust manifold meets the head closest to the firewall (#4).Free Your Head
This is a pretty easy fix, even with the weird head on the MGB. I got a replacement gasket from NAPA, with a tube of the copper exhaust gasket sealant. After removing the gasket from the cardboard, I set the cardboard down next to it so I could align the fasteners to the relative position from where they came. This was so I could track which ones came from where when it came time to put everything back together again. I started with the nuts which held the intake manifold on. One at a time, I would remove the nut and washer, and then set them down relative to where they belonged on the cardboard. Once the nuts holding the intake were off, I slid the intake off the studs, put a latex/rubber glove over each intake to keep foreign debris out and then gently set the intake against the inner wheel well.
With the intake off, I shifted to the exhaust nuts, following the same pattern of one-at-a-a-time and setting it in its relative location. Once the nuts and washers were off, the exhaust manifold slid off and it could be lowered out of the way. Now, the old manifold gasket was exposed.Scrape Your Face
Most of the old gasket came off in one piece, but some bits held on, and needed to be scraped off. Once the main gasket was off, I took a razor blade and scraped the entire area clean. I followed that with 150-grit sandpaper to make sure the head surface was completely clean. I checked the manifolds for residue, but scraped and sanded to be absolutely sure I had clean, flat surfaces. With the surfaces on both the head and the manifolds shiny clean we were ready for reassembly.
Copper Permatex
There are so many kinds of sealants and gasket makers on the market, going simply by color can be a dangerous thing. When it comes to Permatex, the genuine article, the colors match what you think they would be. Still, read the package before you use any. For helping the exhaust and intake manifolds on a MGB to mate to the head, you want to use the copper. It has thermal qualities which assist in keeping the temperature between the head and manifolds consistent while holding the seal at very high temperatures. I put a thin bead on both the head-side and the manifold side, not knowing which side needed is more. Following the instructions, I attached the manifolds finger-tight, waited an hour and then torqued them down.Testing
The following day, the car was ready for another test drive. This time, I took T with me and we laughed as we tore around the neighborhood. The brakes felt good, the gears shifted tight. Most importantly, the exhaust wasn't popping incessantly and the overall din wasn't too bad... under 30mph. The next day, T took the car out, picked up his brother and ran it through DEQ. I posted on that earlier.
Next
Since the car made it through DEQ, I can focus resources on a good exhaust versus the strung-together with bailing wire and soup-cans exhaust that's in there now. I looked high and low for a Peco, but they aren't manufactured any longer. The few that are on the market are the leftover stock, and they are priced accordingly. I considered the Tourist Trophy, but the sound samples I've heard didn't grab me like the Peco did. Part of that could have been the tinny-ness of the stainless steel, but I have heard that as the stainless ages, the tinny-ness fades away. Then, I learned from the fine folks at EnglishParts.com that the stainless steel Bell systems are built with the same design (and tooling) as the mild-steel Peco ones were. So, given time, the stainless Bell system would age into a sound just like the Peco... in theory. Food for thought.That's it for today. Thanks, as always, for following along-
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