Reply To: Oil bypass routing

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Hi Bill,

The bypass valve (“oil relief valve”) has an internal spring and piston which opens if the OIL COOLER is clogged. (The oil flows first from the oil pump outlet under the water pump to the filter, then to the “T” where it goes to the cooler and the bypass valve simultaneously.)  I see no part number break in the 1933 parts book.  My ’33 sedan has the single outlet valve like Larry’s and is engine #235328. Here is a picture of the four types of relief valves known (courtesy of John Cislak).  Your two appear to be identical to each other (with slightly different fittings) and are the Seagraves 8-cyl type on the left (without the small oil gauge fitting shown in the pic.)  (1933 P-A 8-cyl oil gauge tube comes off at the back of the block, while the rest come off the valve body.)  If you want to be absolutely authentic, you need the one on the right.  Otherwise, just use the side connection on your two and plug the straight connection (or vice versa, whichever lines up or appeals visually).  If you block off the oil cooler like some of us, you can remove the spring and piston in the valve so the oil flows thru the valve a little quicker on startup.