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Studebaker M15A-20 "Mr. Potato Head"

Wednesday, July 31, 2013

Electric Fuel Pump Upgrade

Because today's fuels suck leaving us with sporadic vapor lock I decided to upgrade to and electric fuel pump with a fuel line return. Having the fuel pump away from the heat source (engine) helps and the return line provides a constant cooler fuel supply to the carburetor. There is a reliability tradeoff but I don't know what that result would be but I would rather an electric fuel pump to fail as opposed to the engine crank case filling with fuel...

 This is the return line termination at the filler pipe just inside of the cab. I bent a piece of 1/4" plate steel to the curvature of the filler pipe and welded it onto the filler pipe. the plate was drilled and taped for a 1/8" MIP to 5/15" inverted flare ell and a Cunifer pipe ( ) connected.

 This is the return line coming out of the floor where I drilled a hole for a rubber 5/16" ID grommet.

 Here we have the manual fuel cut-off valve, fuel filter and fuel pump. I made a mounting plate that attaches to the frame on the bottom and back. The back of the plate is attached by two 2" long 1/4-20 standoffs. This is a 6 volt Carter pump that has both power lines isolated so it can be used on positive or negative ground. The 5/16" Cunifer line from the fuel tank is in a loop (partially shown) to allow tank movement from frame twisting. The only issue here is that there is a hard connection between the fuel pump and the fuel filter conducting the fuel pump vibration a path to the frame. There is a reason why Carter provides hose barbs with their pump!!! Future plan here is to replace the hard line with two 90 degree MIP to hose barbs and run hose between the two to provide a vibration isolation loop. The good news is that you can stop at a traffic light and KNOW that the fuel pump is running (assuming the stereo is turned down)...

 Here is the two connections to the carburetor front one is the fuel supply and the rear (red) one is the fuel return. I painted the fuel return 1/8" MIP to 5/16" inverted flare adapter red to identify it as modified. To modify it I filled the fuel path with 50/50 solder and then drilled a 0.04" hole to provide a restriction. The two rubber hoses are the standard hose used to connect the fuel line to the mechanical pump in a standard M truck that I bought from SP.

 Here is a picture of the bracket I made to hold the two lines leading up to the carburetor. This is basically an aluminum "L" bracket that holds four rubber insulated 5/16" clamps. Bracket mounts to the top on the frame.
 Another view of the bracket looking straight down. the two lines are routed under the engine cross member with the brake line to the passenger front side.

This is a picture of the passenger side of the engine showing the oil pressure switch for controlling the fuel pump. This is a 5 LB SPDT (Single Pole Double Throw) switch that provides power to the fuel pump when starting the engine and when there is oil pressure and ignition on. I have this switch controlling a relay that in turn powers the fuel pump. Probably not necessary but I installed a box containing eight 60 AMP relays and this setup will reduce the load on the pressure switch giving it a longer life in addition to drawing less current on the ignition circuit.

Thursday, July 18, 2013

Cooling Upgrade

When I got the truck it had the stock radiator. When I got the engine rebuilt the engine would over heat when idling for for an extended time like at a stop light when a fire truck caused the lights to cycle to be off on a hot summer day. No problem cooling while moving at speed. I checked around and could not find anyone in the area to re-core the radiator. So I bought an aluminum radiator from Summit Racing. Didn't fix the problem because there was no fan shroud and the fan was just "twirling in the wind". Parts manual shows that M15's didn't have a shroud. So I bought a six blade flex fan and a universal shroud.

Marking where to cut to clear the radiator support cross member
 Marking to cut the bottom grill plate

 I made radiator adapter members out of aluminum angle and tapped the radiator mounting holes for 5/16"-18

 Decided to just remove the entire support since it would be difficult to cut on the truck. The support is not structural anyway.

 Had to use a fan spacer because the new fan blade extended back to much and interfered with the belt and whatnot. Had to modify the spacer because the Stude water pump shaft had a larger non-standard pilot.

 Here are the old old Stude fan and the new fan. Not hub pilot hole different size.

  Fan installed with spacer

Marking in shroud for fan cutout
 Shroud cut

 Fitting fan ring

Fan and shroud installed. I have not yet installed the fan ring. May not unless I have a over heating problem. With ring installed it becomes very difficult to replace the fan belt on the side of the road...

Looks like the over heating problem solved. Let the truck idle for quite a while today in 95° weather.

1 - AFCO Radiator, AFC-80147-S-NA-N (fits 38-46 GM Truck)
1 - Derale Flex Fan, DER-17015
1 - Summit Racing Fan Shroud,  SUM-380459
4 - 1"x1"x24" aluminum angle

Monday, July 1, 2013

Rear Main Seals

Here is the rear main seals I have to use:

 Top seal is from vendor A and the bottom is from Studebaker Parts. They share the same "GSK051" vendor part number. I have only seen this number used by Studebaker Parts

 This the seal package from a vendor that does not repackage and uses the original Best Gasket packaging.

 Here is the package for a McCord NOS seal

The top seal in identical  to the Best Gasket seal, Studebaker Parts, and Studebaker International AND vendor A. This seal has no markings and has a impregnated fabric strip for sealing. The bottom seal is the McCord seal. It is marked with "Brummer" molded into the rim along with the Studebaker part number "531326" and "STUDEBAKER"