The Stovebolt Site Forums The Shop Area Engine Shop 261 oil flow question

Started tear down of the 261 and I'm a bit perplexed on how the PO(s) had the oil lines routed. It looks to me as if the line out to filter has a plug in it. Return side has a small fitting. Anyone got any ideas or have seen this setup before?

http://i1162.photobucket.com/albums/q530/miami54hydramatic/261%20oil%20lines/092.jpg

That one has never had a filter installed. The small fitting is for the oil pressure gauge connection. If the dowel pin near the oil pan rail was pushed in, the block would be set up for a full flow filter with large pipe fittings. Since both the large and small diameter return ports near the oil pan are plugged, the engine was never equipped with a filter. You'll need to decide whether you want a bypass filter or a full flow, and plumb the block accordingly. Bypass filters do a better job of straining small particles out of the oil so the ideal situation would have both types of filter.
Jerry

Thank Jerry. What's required to run both filters?

My 2 cents, is now's the time to get that plug pushed in (not always an easy task) for full filtered oiling. I had a difficult time when I did mine and so left it out as is yours, should have drilled it out or what ever it takes.

Obviously, you'll need two filter canisters. One would need to be the regular style bypass filter with a small-diameter orfice to restrict the oil flow through it, plumbed with the small flex lines we're accustomed to seeing. That filter housing should contain a very fine-media element capable of straining out microscopic particles of dirt. The Frantz-type filter that uses a roll of toilet paper would be a good choice for that one.

The full-flow filter is plumbed with large-diameter lines, 1/2" NPT, I believe, and carries the vast majority of the oil pump output through the filter on its way to the bearings. This one has to be open-weave enough to pass sufficient volume to give the engine the luubrication it needs. For convenience, I'd choose a spin-on filter for this application. Basically, a full flow filter is there to strain out the big chunks that could damage bearings, score the crankshaft, etc. Most of the old Cummins and Detroit engines I used to work on had dual filters, one full-flow and another one a bypass type. Of course, some of them had an oil change interval of 10,000 miles or longer, and on the ones with the Frantz system we just changed filter elements every 10 or 20K miles, topped off the oil level, and never changed the main crankcase oil. It was still testing good on a spectrometric analysis after over 100,000 miles.
Jerry