Hastings LF405 - June 4 Update

Edited by Dave(inMA) - 04 Jun 2017 at 9:34pm

Thanks, Doug. It LOOKS like it oughta be okay - slightly concave on the business end and what appears to be cotton inside, looking through the hole for the tube.

So with the right type of filter, anywhere in "Normal" is okay?

Thanks, Bill. Nice to bring a little experience to bear on these topics!

Being a bypass filter, if the oil is getting through the filter too well it causes low oil pressure.

Some years ago all the filter makers went to a paper filter and destroyed a bunch of AC tractor engines because the oil flowed too easily.

The oil gets to the filter when the pressure regulator (ball and spring) valve opens. If the filter doesn't have enough restriction the oil pressure drops more than desired when passing through the oil pressure regulator valve.

Gerald J.

Thanks for the replies. I'm a little confused, though. Here's how I'm reading them: Gerald's suggests that the low reading means not enough back pressure and that might destroy the engine. Steve's suggests that I'm probably ok but maybe want to switch to 10W-40 (vs the 10W-30 I'm using). Can someone untangle this for me? Thanks!!

I wanted to report back after trying a couple fixes. First I switched to a Fram C159. Pressure still read low. I then removed the center tube and inspected it - it was open but corroded - mostly on the exterior. Replaced it and now pressure reads in the Normal range. Could be that the  corrosion was impeding oil flow.....

That's possible, Doug. It's one of those minor mysteries of life, I guess! :)

Dave, your still looking at this like an automotive filter... YOU THINK you want to pass a lot of oil thru the filter and keep the pressure high going to your bearings.............. This motor does NOT work that way... Lets say your pump puts out 100% of a given flow... The "TUBE" in the filter has a pin hole in it and allows 15% of the oil to be filtered and DUMP BACK TO SUMP... YOu only get 85% of the oil going to the bearings for lube.. If you REDUCE the size of the hole in the tube, you might leak 10% of the total oil back to sump, meaning you would put 90% of the oil to the BEARINGS........... In THEORY the highest flow and pressure to the bearings is obtained when the filter is PLUGGED or the hole in the center tube is RESTRICTED..

Edited by steve(ill) - 13 Jul 2017 at 4:54pm

Wow! Thanks,  Steve. You're certainly right about how I've been thinking about this. But given your explanation, isn't there a trade-off between the oil quantity getting to the bearings and how much gets cleaned by the filter in a given time? If 85% to the bearings becomes 90%, that's a 6% increase in that flow.....but the flow through the filter would drop from 15% to 10% which is a 33% reduction. I'm not sure I'm thinking about this properly, but if I am, wouldn't I want to avoid cutting the filtering action by 1/3 if the flow to the bearings only increases by 6%? I guess it'd depend on whether 85% is "enough", right?