RedDog382

Recently lost oil pressure in one of my engines at idle. Shut it down right away and found about five quarts of oil in the bilge. Found the source to be a cracked fitting.

After replacing the fitting and refilling the oil, I have had high oil pressures at warm idle. Cold start and above idle oil pressures are similar to unaffected engine (about 60 psi), but guage says 40-44 psi when returning to warm idle while other motor is 20-24 psi. These pressures are distinctly different than prior to loss of oil from the broken fitting. I have replaced the sending unit with a new one with same results.

I wondered about collapsed oil filter(?). I am going to try replacing the oil filter (WIX Racing) to see if it corrects the problem.

I will then try a mechanical guage to see if electrical readings are accurate.

Any other ideas or suggestions?

Mr Gadgets

40-44 at idle is more normal. I would look at the one with the 20-24. It seems low to me. Do the mech gauge, that will qualify the situation.

RedDog382

Oil pressure before the incident was 20-24 at hot idle, always has been, 5 years on both engines. Something changed when I broke the fitting and pumped most of the oil out of the engine. If I scored a bearing or other damage from running with low oil pressure, I would have expected a relative drop in oil pressure. But the oil pressure went UP! Something is not right.

Pwrbt33

iTrader: (2)

Be sure to check the hose that you put into the fitting as well. Sometimes when you tighten up the hose in a new fitting they like to spin with the nut. I had one do this when I re-rigged an old 465. When I thightened up the hose, the brass hose end spun and actually collapsed. Lucky for me I seen it do it was able to replace it with no other harm done.

Just my .02 ...

John

RedDog382

The fitting was just a small extension on the oil pressure safety sensor to get it away from the block for clearance. It has been eliminated.

Mr Gadgets

did you try the mech gauge yet.. on both? It doesnt seem logical, like you say??

RedDog382

Just worked four straight night shifts in a row and haven't had time to dink with it yet. On my way out now to find a Super Duty MF oil filter wrench ... bend my standard one trying to get the GD#*%! filter off.

Geuss I might as well pick up some fittings/line for mech oil pressure guage while I'm at it!

Leathl_WS6

This my be a stupid question but you did put back in the same weight oil?

Also is the opening in the fitting you used the same size as the one you took out. 24 seems low to me as well.

A scored beering could raise pressure. It could give you less clearance and raise pressure.

RedDog382

Same oil Mobil 1 15W-50. Was 24-25 psi hot coming off hard run, always has been. This is hot idle in gear at 450-500 r.p.m.

Broken fitting between warning buzzer sensor is deleted, now threaded directly to block.

My gut is telling me this is likely a guage problem. I'm going to put a fresh filter on, then change guages side to side to see if it follows the guage. This will be easier than putting a mech guage on temporarily.

Engine ran fine all day Saturday. I think I would have seized or melted down if it was a scored bearing.

Thanks for all your input ... I will post findings when I get more time to investigate further.

RedDog382

This is actually not a stupid question.

Motors were out this winter for upgrade to Stef's pans, fresh oil pumps, thermostatically controlled oil coolers, and oil pressure reliefs.

Motors were dyno'ed on natural oil (? wt). Pans were then drained and refilled with the Mobil 1 15W-50, but there was probably considerable residual natural oil left in lines, cooler, and filter. So what I pumped out was a blend of natural and synthetic replaced with synthetic.

Any opinions if this would make a 15# difference at hot idle?

Maybe I need to change out the oil in the other motor!

And maybe I'm going to own Leathl WS6 a couple cold one's if I get to Cleveland this summer!