As seen in Speedboat Magazine’s
Nov/Dec 2020 Issue.
Oil Pump Pick-Up
Dear Bob:
I am building a pair of 555 cubic inch naturally aspirated engines, using the Melling 10778C oil pump and an 8.5” deep pan that was on the engines (Originally Mercury Racing 600 SC). What pick-up do you recommend?
Marshall Fall
Smyrna, TN
The pick-up needed for the Mercury pan is the one that is designed for that pan which comes welded to the oil pump on a variety of marine engines. In order to properly install the pick-up, you should mount the pump on the rear main cap with the pick-up tube pressed into the pump. Next, with a straight edge and a ruler or measuring tape, move the pick-up so that the screen cone is parallel to the engine block’s pan rails. Then, carefully remove the pump without disturbing the pick-up position and braze the pick-up to the cast iron pump housing.
GM/Mercury big-block Chevy oil pan.
Alternative pick-ups are available that are also supported by a bracket that is bolted to two of the pump cover bolts. You may have trouble finding one that is the correct length for your stock pan. The oil pump pick-up screen should be about 1/2″ from the bottom of the pan. If it is too close, oil starvation could occur resulting in engine damage.
Oil pump installed with after-market pick-up.
Your Melling 10778C pump cover is held in place by five 6×1.0 metric bolts. If you use a pick-up with a support bracket, you will also have to provide bolts that are longer to compensate for the thickness of the bracket.
As a side note, Melling makes a version of the pump you have that does not have the “anti-cavitation” feature. The part number is the same, but without the “C.” We have found that the idle oil pressure is generally lower with the 10778C, and sometimes takes the pump a little longer to prime.
Replacement Fuel Tank Pick-ups
Dear Bob:
I’m working on a 37’ Talon offshore cat and I want to replace the pickup lines in the fuel tanks. They are a stiff plastic type that is 3/4” inside diameter. I just don’t know what the com-position is for the material. This tubing measures .750″ ID, and the wall thickness is approximately .065” and each one is 24” in length. Can you help me with this?
Barry Annis
Newcastle, CA
Most aluminum fuel tanks have 1/2” NPT bungs in the top where the fuel pick-up tube and fitting screws into. Over time, the plastic tubes start getting brittle and results in an air leak at the connection point. This can cause aerated fuel or in severe cases not being able to pick up fuel from the tank.
The best solution is to change the fittings and tubing using a brass adapter that is 1/2″ NPT (assuming that the tank bung is 1/2″ NPT) to -10AN (or whatever the size of the fuel hoses are).
The tubing we use is 1/2″ type L copper which measures .625″ OD. The length is determined including the fitting. It is best to have the bottom of the tube about 1/2″ off the bottom of the tank when installed. Also, cut a 45 degree angle on the bottom of the pick up tube. Put the adapter fitting in the lathe and bore the hole at the pipe thread end with a 5/8″ drill. It is only necessary to drill into the fitting about 3/4″. Clean the top end of the tube with Scotch-Brite or something similar. Put soldering flux on the tube and fitting bore and push the tube into the bore in the fitting. Using a propane torch, “sweat” the fitting and the tube together the same way you would with a copper water pipe.
The same procedure can be used for fuel cells with precautions. Most fuel cells have a plate in the top with pipe threads that can be used the same as a bung. You can make the pick-up tube in the same manner, but extra caution is necessary to protect the cell. If the plate is removable, you can screw the pick-up tube assembly into it. In this case, you can make the tube a little shorter and clamp a piece of vapor barrier fuel hose on the end to protect the cell.
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