The Stovebolt Site Forums The Shop Area Engine Shop How important is full pressure filtration?

I think I goofed here guys. I have a fresh 57 235 sitting at the machine shop that's basically built up to a long block. I just discovered the bypass vs full pressure idea and am wondering if it would be worth it to have my guy go back in and change to full pressure? I'm not so much worried about less oil being filtered as the drop in pressure from a bypass filter.

Untold millions of stovebolts have run hundreds of millions of miles with bypass filters, including the ones that helped win WW II. Leave well enough alone and worry about something worthwhile like the rising price of beer! The whole thing about full flow VS bypass oil filtering is a solution in search of a problem. Converting a 235 to full flow filtering involves a total teardown to a bare block and some pretty sophisticated machine work, all so you can get worse oil filtering than you had before. Oil pressure loss through a bypass filter is a myth.
Jerry

Amen (maybe?)

Thanks, I feel better now. It's just that these engines aren't exactly cheap to rebuild and I want to get a lot of driving done with this engine!

An extra thousandth of clearance on the rod and main bearings will cause more pressure drop than the tiny amount of oil that gets returned to the oil pan by a bypass filter. I'm working on a project to put small block V8 pump gears into a stovebolt housing that will result in about a 20% increase in oil volume. When that project is done we're likely to see 216's with 30 pounds of oil pressure at idle, even with a bypass filter onboard!
Jerry

This might seem stupid but I have run my 1954 235 with no filter for over 31000 and just got back from KC, 1300 miles. The reason for no filter I had a remote spin on filter and the gauge read near zero so we took off the remote I run with out one. Could that be a problem? I am thinking of putting the canister back on.

Ron, the reason your gauge read low could be because the spin-on filter did not have a restriction in it and was running full flow. If your oil pressure was bad with the filter connected and good when it was disconnected indicates that was probably the problem. The canister has a 1/16" restriction about 2/3 of the way up the inner tube. That will not cause a meaningful reduction in your oil pressure.

Matt

How often do you change the oil?

What oil do you use (detergent?)?

If you use detergent oil and change your oil annually and/or every 3,000 miles, my bet is you and your engine are OK.

Ron, if you can email me some pics of your remote filter setup I can tell you where to drill and tap one of the fittings for a restrictor bushing (AKA Holley carburetor jet). It will bring your oil pressure back to normal. I might even be able to suggest a spin-on filter that will work as well as the original canister filter, as the ones intended for full flow oiling don't do much actual filtering- - - -they just strain out the big chunks.
Jerry