O.K;
From the "don't ask me how I know" category......
If you want to run an exhaust pipe through a wood wall, the safest way to do it is inside a 36" (or longer is needed) piece of 2100 degree wood stove piping - the heavily insulated kind you see on the outside walls of houses. Usually the 6" or 7" size is good, simply cut a suitable sized hole, push the wood stove piping through leaving about 6" or more protruding on each end, then put your engine exhaust pipe through that. Seal the whole thing up with concrete and off you go. Try to get the exhaust pipe off the walls of the stove pipe by putting non-flammable blocks under it until you can get the concrete in and set.
Generally the exhaust pipe of a Lister is not hot enough to set a wood wall on fire, but WHEN you have an exhaust fire caused by burning soot deposits then the red-hot pipe most certainly will ignite things - please refer to the first sentence........