VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 1954 chevy 3100 mechanical fuel pump

Hello. I am a 16 year old male who recently picked up a 1954 chevy 3100 1/2 ton truck with a 235 inline 6. It is a barn find that has been sitting for at least 20 years with gasoline in the tank. Now it just smells like paint varnish from sitting so long. I have arrangements to replace the fuel tank and sending unit already, and plan to flush out the main fuel lines that go to the mechanical fuel pump and to the carb. I assume that the fuel filter located on top of the mechanical pump will need to be cleaned out as well to flush out any of the old fuel that has been sitting. I would think all this is necessary, but that's why I am here. Would it be fine the way it is, or am I correct in flushing the system? I led jumpers to the battery, poured some fuel in from the top of the engine, heard it crank and fire, but stopped there before it rolled over since I don't have the air filter on the carb or fuel lines in place.
Thanks for your time,
Sam

If it were my truck ,and I wish it were, I would put a in-line filter before the carb. clean up the fuel pump with a new filter and run it. with the gas tank clean, old gas was probably have drained backwards into the tank. There are some who will say rebuild the carb..If it works and does't leak.. run the truck. Your year is a great year. Drove one for years. Bill........welcome to the club..P.S replace belt and hoses

Mechanical fuel pump diaphragm probably pretty brittle after all these years. When they start leaking, they can fill the oil pan with gas pretty fast.

I would just bite the bullet and replace the fuel pump. You will probably have carburetor problems also.
Once you get it runing plan on doing some cooling system work as well as the brakes.

If the engine has been sitting for some time, I would drain the oil and put in fresh, pull the distributor, hook a drill into the oil pump with a screw driver and get oil pressure that way. While doing that, you can also roll the engine over by hand. This will insure that most of the moving parts will at least get some oil before start up. Another way to do this is simply disconnect the coil wire and roll it over with the starter thoroughly to get oil pressure, but personally I prefer the first way as you will get better pressure without undo stress on the starter.

If it were mine after you get it ready to start the engine I would change the oil, using 10W-30 for refill. Remove the spark plugs and put about 2 ounces of Marvel Mystery Oil or automatic trans, fluid in each cylinder and let stand over night. The next day turn the engine over with the starter (with plugs out) for about 30 seconds. This willl get the oil pumping and the MMO or ATF will give the cylinder walls some lubrication.
Plan on some cooling system problems if there was water or coolant in the system for 20 + years.

Radiator is in the shop now being repaired(leaked in one tube) and I plan a disc brake conversion since I am sitting with no brakes

Once lubricated do I worry about draining out the MMO or ATF? I had planned to lubricate the differential that way, letting sit for a day then turning the wheels A LOT.

Good advice on removing plugs and adding Marvels....and turning over with the plugs removed will reduce strain on starter. Pistons will push the majority of the oil out. Combustion at start up will burn off any residual oil.

If you let it sit overnight as I mentioned the MMO will have soaked past the pistons and most will end up in the motor oil. Will not harm anything there and actually help. I should have mentioned I would remover the rock arm cover and squirt some MMO on the valve guides. This can be done bt going in between the valve spring coils. Turn over the engine slowly at first to make sure no valves are sticking.

Sam,
Good to see a young man, with such dedication to doing the job right.

If you plan to keep this truck, take the time to find a reproduction GM Service Manual, for your specific vehicle.

Note that I suggested the GM version of the service manual and NOT a Haynes or Motors Manual. Those two manual omit items and may have ( do have ) incorrect info and specs.

Until to have a hard copy, here is the GM online copy for your 1954 Truck.
http://chevy.oldcarmanualproject.com/shop/1954truck/index.html

FYI, folks routinely use MMO in the fuel tank, mixed with gas .... also use the MMO with engine oil, as well.

Good stuff .... and welcome to the world of VCCA !