Now we have this 1952 American LaFrance Fire Truck and instead of using it as a parts truck the customer has decided he wants it also running and roadworthy. So our engine rebuild job begins. The goal is to save this engine. It will definitely be a challenging job.
This was an old-fashioned, in the chassis, engine rebuild.
There were valves rusted in the valve guides and burnt. The heads were magnafluxed and all other parts were check and look good. We cleaned all parts and did a valve grind, and were able to use parts from the 1946 Truck heads. All-in-all, we were able to reassemble two complete heads. The thermostat was completely plugged with rust and debris which probably caused the head gasket problem.
These engines have two heads and six subheads. The engine would not turn over because the rings were rusted to the cylinders. We soaked the pistons for three weeks and they still did not break loose. The only option is to have the pistons custom made. We gave it one more try and started to remove the pistons that we felt would move a little and were able to get eight of them out. The connecting rod does not come out through the top with the piston, so we had to push the piston out of the cylinder and hold it up, remove the wire clips and remove the piston from the rod and then pull the rod from the bottom of the engine (a two-man job). Four pistons would not move. Trying to force them out is when they would usually get broken. With a lot of talking and soft touch, we were able to save all twelve pistons. We had Hastings pull out old blueprints and they made a set of rings for us (four per piston). We had to really massage the bearings because there are none to be found. We did hone the cylinders slightly to get a smooth surface so the piston rings would seal.
While all that was being done, the fuel and cooling systems were checked out. Rebuilding the two Zenith carburetors, fuel pump, water pump, and sending unit were necessary as was resealing the fuel tank.