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  #1   IP: 24.178.35.35
Old 07-07-2006, 08:38 AM
Mark Harrington Mark Harrington is offline
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Oil Pressure / Rear oil seal - Next step

Don & All,
I have done the following:
cleaned oil pressure regulating relief valve seat
Replaced oil 30 wt.
At 1600 RPM oil presssure 7 psig when at operating temperature
cleaned oil pressure regulating relief valve seat including using some carb cleaner
Replaced pressure gauge with a new one
Installed a stiffer spring
Added 10W 40 oil
At 1600 RPM oil pressure 7 psig when at operating temperature

When engine is is first started and oil cold pressure is is 35-40 psig then drops as engine warms up.

When warmed up 800 RPM oil pressure is 5 psig, at 1600 RPM oil pressure 7 psig, at 2400 rpm oil pressure is 9-10 psig.

Is there any way to confirm the oil pressure relief valve is not leaking?

What oil pressure is required for oil pressure switch to close and allow engine to run?

Engine runs and idles well without any unusual noise.

The rear oil seal at transmission output shaft has a slow but constant drip when engine is in gear. Could this cause the low oil pressure? I wrapped a 2' wide strip of white bed sheet around a rope tied it around the transmission case to confirm oil drip was not from the front of the engine. Are any special tools or techniques required to replace the rear oil seal? Should any other parts besides oil seal and gaskets be replaced during this repair?

Is there a way to determine if the low oil pressure is due to the oil pump or the bearing clearances? Can anything else can cause low oil pressure? Do you recommend replacing the oil pump components during an overhaul?

What is your recommendation on how to proceed from here to get the oil pressure up to the specified value?

Regards,

Mark Harrington
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  #2   IP: 38.118.52.41
Old 07-12-2006, 10:07 AM
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Don Moyer Don Moyer is offline
 
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Mark,

The fact that your engine idles without shutting down allows for some hope that your indicating system is not functioning properly. The oil safety switches used by Universal were mostly in the range of 15 psi and the switches shown in our online catalog close at 10 psi. Either of these switches should have shut you down, especially if you have an original Universal switch.

The other obvious reason for hope is that your engine is still operating normally with what would, in most cases, be a dangerously low oil pressure. This of course raises the question of how long your pressure has been in this range.

There is very little that can be done externally to the engine (other than what you've already done) if it turns out that your oil pressure really is as low as yours is indicating. It's also difficult to differentiate between the different possible causes of the low oil pressure. I can say that your pressures are consistent with what we would expect if we inadvertently left out one of the internal oil galley plugs in the course of a rebuild.

I'm attaching a recent Q & A on the subject of changing a rear oil seal.

Don
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File Type: pdf Changing a rear seal.pdf (12.7 KB, 1270 views)
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  #3   IP: 24.178.35.35
Old 07-13-2006, 09:20 AM
Mark Harrington Mark Harrington is offline
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Oil Pressure more questions

Hi Don,

Thanks for the reply and information.

I will try the snubber and new oil pressure gauge first in addition to other checks you suggested on the phone.

If the oil pressure is still low, do you have a sketch, diagram, or description of where the the three internal oil galley plugs are located? What engine components have to be removed to inspect them?

I plan to pull the engine this weekend because in addittion to low oil pressure, rear seal leak , the propeller shaft radiator type hose is leaking.

If a plug is not missing then the other possible problems are blocked suction side of the oil pump, defective oil pump, or out of specification bearing clearances. Is there anything else to check?

I want to solve the oil pressure problem first.

Regards,

Mark Harrington
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  #4   IP: 38.118.52.41
Old 07-13-2006, 04:13 PM
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Mark,

We'd have to begin looking at bearing clearances at that point.

Don
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  #5   IP: 24.178.35.35
Old 07-20-2006, 09:32 AM
Mark Harrington Mark Harrington is offline
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I added a needle valve and purchased a new pressure gauge even with this set oil pressure still read 7 psig when engine warmed up.

I took oil pressure switch to autoparts store their data indicated models available set to close a either 4 or 10 psig. If gauge is correct this one must be set at 4 psig.

After removing engine boat placing on engine stand and removing crank case we found all three internal plugs were inplace. We check the flyswheel end main bearing clearance with plastigauge, it checked out greater than .003 in.. We then removed crank shaft.

Crank case had some oil sludge in it and part of the screen was covered in oil sludge. Screen had a few holes in it.

Removed oil pump cover plate. No visible defects with oil pump parts.

Now considering how to proceed.

Mark Harrington
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  #6   IP: 76.22.107.152
Old 11-23-2008, 10:48 PM
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Mark Millbauer Mark Millbauer is offline
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Another Low oil pressure problem...

Don and All,
Since I have had my A4 (about 3 months) it has displayed 20 lbs of oil pressure at all RPM's. Last weekend I warmed her up and successfully adjusted the oil pressure to read 35-40 lbs. Great! This weekend when I got to the boat and fired her up, she displayed only 10 or 12 lbs regardless of RPM. there was no difference after cleaning the contacts on the gauge and sending uni.

This is a later model engine. It only has 20 hours on the last oil change of 30W and the oil still looks good. Compression is good too so I assume the motor is probably in good condition. What could have caused the change in pressure after sitting for just a week? Broken oil pressure relief spring? Stuck ball? Should I order the new kit that has the old style relief valve? Did I adjust it to high and break something?
BTW, this is a Catalina 27 and the oil pressure adjustment is very hard to get to. Thanks in advance for you help.

Mark
C27 "Solution"

Last edited by Mark Millbauer; 11-23-2008 at 10:50 PM. Reason: Add my name
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  #7   IP: 38.102.24.196
Old 11-24-2008, 08:51 AM
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Mark,

I'm sure you didn't break anything with your adjustment. Late model (spring and ball type) regulating valves have a tendency to create these kinds of excursions.

If you still have at least 1/2" of threaded shaft showing on the outside of the 3/4" locking nut, I recommend that you try turning the shaft in at least one more turn and then start the engine and check the pressure. You don't have to adjust the pressure with the engine running, but after making an adjustment, all pressure checks should be made with the engine fully warmed up.

If you don't see a positive change after one or two more adjustments, I'd replace the regulating valve with one of our sliding shaft type of valves. These valves (patterned after the early model design) tend to maintain a more consistent pressure.

Don
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