Bypass Oil Filter?

[gleonard]

Well, since there seems t be no compelling reason to do so and doing nothing is by far the easiest course of action, I will leave it as is.  This forum is already saving me a lot of work!

Thanks to everyone for their advice and consideration.

George Leonard

[Jim Benjaminson]

I simply plugged them - no ill effects after all these years....

[TodFitch]

The oil goes into the filter from the high pressure galley that feeds the bearings. The exit from the filter goes through a portion of the pressure relief valve and dumps back into the crank case. The pressure relief valve is setup so that if the oil pressure is low then flow through the filter is cut off.

If you just put a piece of tubing in place of the filter you will, if your pressure relief is working correctly, simply drop your oil pressure to the minimum. If your pressure relief is sticking or otherwise not working properly you may end up with no oil pressure at all. You would be promoting the flow of oil but only between the pump and the crankcase, not to the engine where it is really needed.

Far better to plug the openings than to put a piece of tubing between them. On the other hand, the bypass filter really does a reasonable job at cleaning the oil so why not leave it in the system as it was designed?

[gleonard]

Hi Tod,  Thanks for your reply.  I really wasnt going to plug up the oil lines.  I was going to install a piece of tubing in place of it in order to let the oil flow freely.  Unless you think that plugging it would be better, that is the route I was prepared to follow in the interest of promoting as much oil flow as possible and just in case the originality bug should bite me, it would be easy to reverse.

George Leonard

[TodFitch]

The sealed canister oil filter you have is a "bypass" filter. The failure mode on these is to clog up and simply stop passing oil through. So taking it off and plugging up the lines does not really buy you anything.

Since the failure mode is benign (unlike a modern full flow filter) you can safely extend the interval for replacement. I change my oil about every 2,000 miles on my 1933 but I only change the filter about every 10,000 miles. Don't do this with a full flow filter as there is a pressure relief valve in a full flow filter that will open up if the filter becomes clogged and it will then dump its accumulated gunk into the bearings.

The last manufacturer that I am aware of for this filter (WIX) stopped making them about 5 years ago but they are still available through swap meets and eBay. You can see a list of the various obsolete numbers for this filter to help you in your search at: http://www.ply33.com/Parts/group10#10-C

[gleonard]

I just acquired a 1949 P18 and am wondering if bypassing the oil filter is a good idea?  Mine is the non cleanable type.  Since I dont know what in the world might be hiding inside it, Id like to just eliminate it and just change my oil more often to make up for it.  Originality is not a high priority for me. 

My main concern is that if I put high detergent oil in the crankcase, it might dislodge some gunk that has been sitting in there for a long time and just minding its own bussiness.  The only way to eliminate that possibility would be to eliminate the oil filter, right?

George Leonard