Re: 1951 oil filter

Posted by HH56 On 2024/6/18 16:33:18

Plumbing sort of depends on which version filter you have and your block casting. Starting in 51 the blocks should all have a cast in port for the filter oil return located in the block just above the oil pan. If the car never had a filter this will be unused and plugged. On those blocks, oil drains out of the filter and drops straight into the pan. On 50 and earlier 288/327 blocks there was no return port so filter return oil was introduced back into the engine by piping it to the valve lifter gallery supply port (upper port on block). The low pressure and reduced volume out of the filter was adequate if the engine had solid lifters but could cause issues with hydraulic lifters hence the change in 51 to have all filter return oil drop into the pan. If by chance there is an earlier block in the car but it has hydraulic lifters you can try the method in the filter installation drawing but also be prepared in case you need to reinstall the short pigtail and add a dedicated return port if the lifters start becoming noisy or otherwise acting up.

The factory filter canister had several versions and they all look very similar. Unless you know your filter assy is correct as supplied for the 51 car, because of all the mixing over the years if yours came from ebay or a parts supplier you could have one of the earlier versions and will need to determine which one it is so it can be plumbed properly. All the lines were 1/4" steel tubing.

Prewar canisters have a fairly pointed bottom and have the inlet on the bottom and outlet on the side. Those need an orifice in one of the supply fittings to limit the amount of oil that can flow thru the filter. Packard put the orifice in the elbow where the supply tube attaches to the bottom filter port by filling the opening in the brass elbow with solder and then drilling a 5/64 hole thru the solder. Later they put the orifice in one side port of the 4 way brass fitting where the supply line connects to the engine supply port (lower port on block). Second version early postwar filters had a flatter bottom with the inlet on the side and outlet on the bottom but also needed an orifice. Final version filter which a 51 would have had will have the inlet on the side, outlet on the bottom but the orifice is built into the center pipe of the canister via one or two fairly small holes drilled in the pipe. The holes are sort of in the middle to low third of the canister and just above where the bottom of the filter element will sit.

Here are a few photos. Kev already posted the factory install for engines without the return port. First photo is the 4 way block with the filter line on the left and small pigtail to valve lifter gallery port on the right. Second is from the parts manual showing the cast in return port standard on later blocks circled in yellow. That engine is a 356 but the smaller 288/327 blocks have a similar return port just above the pan located a bit closer to the front of the engine almost directly under the oil filler tube.

Attach file:

---

  4 way block.jpg (154.18 KB)


  return port.jpg (49.71 KB)