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Studebaker M15A-20 "Mr. Potato Head"

Sunday, December 23, 2012

Cam Core Plug/Bearing Dilemma

While replacing the rear main seal I discovered that the rear cam core plug was leaking. After removing the plug I discovered that the cam bearing was not installed all the way in the bore preventing the correct cam core plug from fully seating. It appears that the engine rebuilder used a shallow core plug to compensate. I have inserted a stiff wire into the rear oil galley access hole to determine if the cam bearing oil hole is aligned with the block oil hole. One possibility is that the rebuilder DID align the holes but installed the bearing backwards and because the oil hole may be offset it would be recessed on the inside of the engine and protrude on the outside... The only good way to test this is to pressurized the galley and observe if oil is spewing from the bearing.

My current plan if oil does not make it to the cam journal is to press the bearing in and cross my fingers that the oil holes align. If they don't align then I will have to press the bearing out (towards the cam) enough to verify where the oil hole is on the block, align a new bearing and press it in until the holes align, then cut the dangling old bearing off the cam with a Dremel tool cut off wheel. I'm just hoping that the remaining three cam bearings have their oil holes aligned properly...

Original core plug on the right, correct core plug on the left

Rear cam core bore showing the protruding cam bearing

Inside view of rear cam and cam bearing. Note that the bearing is inset about the same distance as the bearing protrudes on the other side.
Cam bearing #3. Note that it is flush with it's bore.

Tuesday, November 27, 2012

T9 Tranny Fun

While the tranny is out of the truck to replace the rear engine oil seal and clutch disc I thought I would upgrade it with new gears and some modifications. This modification is to seal the end of the shift rods so they don't weep oil all over the tranny case. Basically, it is a plate attached to the end of the shift rod bores that seals the end. There are two channels cut into the plate to allow the oil and air to pass to the adjacent bore to relieve pressure when the shift rod travels to the end of the bore. The plate is made from 1/4" thick, 1" wide stainless steel bar. The countersunk bores are 0.625" in diameter, centered on the plate, and spaced to match the the bores on the shift tower. The gasket is made from thin neoprene rubber.

 Here is the block off plate, gasket, and attachment screws
(I have subsequently moved the channel between the bores to the other side of the screw holes)

 Other side of the plate

 Assembled, ready for installation

 Hold plate in position and mark where the mounting holes are with a fine point Sharpi
Note: To get correct positioning, move 1st/2nd shift rod into second gear where it protrudes and position the plate over the shift rod.

 Mounting holes marked

 Center punch mounting hole location

 Drill mounting holes. 0.159 for #10-32 screws

 Tap mounting holes and mount plate

Oil drain back holes drilled just inside the gasket surface

Three holes, one for each shift rod

 I also hogged out a channel for the oil to pass the shift rod with
a Dremel tool

 Bell housing protrusion

 Bell housing protrusion ground down to clear plate

 Transmission shift tower attached
(Yellow arrow points to where the hole was drilled and taped for the vent tube)
 The pipe coming out the side is the added reverse backup light switch. There is a rod inside the pipe that contacts the reverse shift rod and extends out to the push button switch mounted on the end of the pipe.

Monday, November 12, 2012

CVC Tractor Museum Meet

 Farmer Brian

 Plow the field and then drive to a night on the town!


 Farmer John

 Indian made a tractor?

This Ford 8N is just like the one Brian restored

 This CASE beast had a turbocharger and a supercharger in series...