I bought a cast iron 4-barrel manifold from the local pick-a-parts place that was in really rough shape. All the exhaust crossover tunnels that supply heat to the carb base were clogged with hardened carbon deposits. We got three of the tunnels cleaned out, but the fourth one has a clog somewhere that I can't seem to find. To date the manifold and runners have been beadblasted clean, we have soaked the clogged runner overnight with an industrial type oven cleaner, that our turbo shop used to clean turbos, and have soaked the manifold overnight with some type of skin devouring cleaner that is used aroung the shop. I can run a coat hanger with a flattened end in and get a little carbon out that way, but cannot get a passage poked all the way through so the cleaner can work. My next step is to hit it with a torch to see if it can be burned out. Any ideas on how to get this cleaned out, or do you know of any carbon/oil remover that might work. Oh, I forgot, we used the hotsy machine too, that didn't work either. Thanks in advance.
I wouldn't worry about it. In your warm climate the exhaust crossover isn't nessessary and many people purposely block them off.
I worried about where this crap might wind up if it does get loose, will it pass straight out the exhaust manifold, or hang up an exhaust valve. Besides, it's starting to become a challenge to some of our service techs to try to get it cleaned out. Thanks for your response.
Tom T (telriv) once told me he likes to use muriatic acid on cast iron parts....but not for too long of a time! Drop him a line and ask about the specifics.
We soaked it in some kind of green cleaner that they use to clean industrial turbo chargers at our shop. The shop guys call it simple green "on steroids". This stuff eats the rust off cast iron and brightens aluminum. Other than that, I don't know what it is, the jugs aren't labeled.
