Today, I return to the little British car: our 1978 MGB, Oliver. Oliver has sat unused for too long. I had been having considerable and increasing trouble just getting him to start and run. So, earlier this year, I removed his carburetor for dis-assembly, cleaning and re-assembly. I did the removal and tear down what feels like months ago, and just completed the re-assembly. So, while this post may feel like a couple of consecutive weeks of fun, it's really a little from March, a little from June and a little from last weekend.
Removal and Tear Down
re-assembled |
At the work table, I started with the most obvious things and worked my way inward. First, the inspection cover and top half of the carb was separated from the main body. I removed every slotted bolt and whatever lay beneath, taking pictures as I went. Last from the top were the air correction jets and then I removed the set screws that held the venturi to the main body. The main body was effectively disassembled, so I shifted to the top half, removing the float, the fuel inlet bits and the choke bits. Last, I pulled the little cover or plate that faces the intake when installed. I am sure someone who does this often would have done it faster, but I needed to chronicle it so I could re-assemble later.
Carb Cleaning
remove from car day |
The cleaners, well, the one that I got, but from what I read, many of them have a setting to warm up the solution while doing the ultrasonic. From what I read, there was some level of concern about how well they actually maintain temperature and that sometimes they can run the solution too hot. Since the solution is concentrated (read: need to add water), I decided to use boiling water and when poured into a room temperature solution, the overall temperature would be sufficient. I ran the carb body and all of it's pieces in the ultrasonic cleaner for multiple 20 minute cycles. Once I was satisfied that the carb was as clean as it was going to be, I moved it and the parts into a bucket and rinsed them with water. I then set everything out in the sun to dry.
Rebuild Kit
great kit |
Re-Assembly
view from firewall |
I used liquid gasket-maker for the jet inspection cover. That stuff makes a dark sticky mess. The instructions on the bottle say to let it dry "for a few minutes" before putting the 2 pieces together which need a gasket in between. I let that sit for well past the recommended few minutes and it was still very wet.. and even after letting it sit in the sun the stuff didn't dry very much. So, I did everything else install-wise and add the inspection cover dead last.
While I had the carb in hand, I decided to add a heat shield to the underside. The header that I installed has a thermo-barrier powder coating on it, but I know from having the hood open after driving it that a ton of heat is still getting into the engine bay. I suspect the source is the header (or the radiator), and the best thing I could do for the carb is to help prevent heat from getting to it. So, I got a DCOE carb heat shield from Pierce Manifolds. The mounting bolt pattern is designed for a Weber DCOE, but the SK Racing/OER is exactly the same in this area. The venturi maintenance holes line up, the cut-outs for the intakes, etc. it all just lines up. The heat shield is heavier and thicker than I expected, but I expect it will do exactly what it is intended to do: block and route-away heat rising from the exhaust.
Install
re-install day |
I discovered that the heat shield has a small tab on the intake side that would hit the center header pipe. Recall, the MGB has a Siamese head, so the middle 2 cylinders share an exhaust. The PO had a home made exhaust manifold with a center pipe effectively pointed straight down. The header has a more typical curve. So, the heat shield came off and I adjusted that tab to point angled upwards so it did not hit the header pipe, but actually will shield the top-most end of it. Then, I realized that I could not address the lower mounting studs with heat shield installed so I removed it again, re-installing after the carb was nutted down into the intake.
From there, the install was about what you would expect, complete with a dropped bolt under the car. I had to reverse the spring-return arm on the carb as well as flip the fuel inlet. Still, it was relatively smooth, hooking up the fuel line, control cables and air filter.
No Test Fire
By this time, I had sweated my way through most of a summer afternoon and cleaned liquid gasket maker off my hands more times than I'd like to count. As much as I wanted to enjoy the sound of the engine running, I chose instead to take the limited win: Oliver was in one piece. Boo and I went to the county fair instead of test-firing Oliver's engine. Now, Oliver is covered back up, again waiting for me to have a few hours to test fire his engine and fiddle with settings. I sincerely hope the tear down / deep cleaning was what he needed. I'll post an update when I have one.
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That's it for today. Thanks, as always, for following along-
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