Matt Gieselman

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Dodge M37 Manifold Replacement

The manifold on one of my Dodge M37s was in terrible shape with a couple of cracks I decided to replace it, the part numbers below also apply to the 230 in the Power Wagon also.

Note if you are installing a new intake or exhaust manifold you will probably need to have them machine together as a unit so they mount flat against the block.  The forum posting here shows what it looks like when they are out of plane. 

IMG_0862IMG_0865 The exhaust was cracked almost all the way through on the right and fell apart as it was removed.
Manifold 003 Heat riser repair kit from Midwest Military also includes the riser flap not shown.  The stud is 1/4” x 1” with 28 tpi on one end and 20 tpi on the manifold end.
Manifold 007Manifold 008 The heat riser shaft didn’t include the W for winter and S for summer so I used an inexpensive steel stamping set from Harbor Freight.
Manifold 001 The original stud broke during removal, I drilled the old stud out and tapped it with a 1/4” 20NF tap.
Manifold 004 Using my new favorite tool this Snap On Stud Remover/Installer makes it pretty easy to install studs without damaging the threads.
Manifold 006  
Manifold 009 The manual states that the heat riser shaft should be cooled with dry ice, not having any handy I just left it in the freezer for an hour.  Installation was a tight fit.

Next step was to weld the heat riser flap to the shaft, I used a file to hold the flap in position for welding.
Manifold 010 Post welding.
Manifold 038 After removing all of the studs, 2 of which broke I installed all new hardware.  To replace all of the studs you need 11 of Dorman 657-003 and 2 of 675-083.
Manifold 039Manifold 040 To prevent the manifold from cracking after installation it’s important to use the brass bushings and tapered nuts (4 each).  Both are available from Vintage Power Wagons.
photo Manifold and carb after installation.
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