59ab oil pressure relief valve leak

[31blackcoupe]

My '48 239 59ab is pushing oil out the bottom vent, like a lot. I pulled the intake and found the relief spring had bee stretched by the previous owner. I replaced it with an 80lb pressure spring, a new plunger and a new cap. Still pushing it out, but not as bad. Also tried Marvel oil before I took it apart, but had no success. using 4 quarts of straight 30 weight oil. 3 w/the marvel.
Any suggestions? Less oil? Lighter weight oil? Switch to the 50lb spring?
Thanks,
Art

[rotorwrench]

It's normal for the pressure relief valve to exit oil into the timing chest. There should be a tube in the front there that keeps oil from getting down to and exiting through the vent. The pan gasket can also get displaced and cause oil to exit the vent.

[Flathead]

Any excess blowby? Is the oil filler tube vented as it should be?

[Kahuna]

X 2 Rotorwrench. Is the tube in place?

[G.M.]

The relief valve ALWAYS leaks, there is a flat on one side that
always lets a small amount of oil on the timing gears. I like to
adjust the oil pressure with Castrol 20/50 oil and a mechanical
gauge screwed into where the gauge sender is. I use 1/8th inch
pipe as a shim on top of the spring, the hole in the pipe needs
to fit over the top end shaft of the valve. I start with a spacer
3/8" long. With the spark plugs out and a little oil in the cylinders
and the intake manifold off crank the engine with 12 volts. It will
spin fast enough to show you the TOP OIL PRESSURE you will
have driving down the road at 40 to 50 MPH. You can adjust the
pressure by changing the thickness of the shim to get the
maximum pressure you are going to get with the amount of engine
wear and the output pressure of the oil pump. The pump could also
have a relief valve with the same spring issues of the valley spring.
I built a fixture to spin the oil pump with a 1/2" electric drill so I
can tell if there is gear wear or clearance problem or the bypass
spring is weak. G.M.

[31blackcoupe]

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Originally Posted by rotorwrench

It's normal for the pressure relief valve to exit oil into the timing chest. There should be a tube in the front there that keeps oil from getting down to and exiting through the vent. The pan gasket can also get displaced and cause oil to exit the vent.

tube is in there and tight
thanks for the reply

[31blackcoupe]

Originally Posted by Flathead

Any excess blowby? Is the oil filler tube vented as it should be?

no blowby, removed filler tube-fuel pump rod-and tube (electric fuel pump)
still doing it. thanks for the response

[31blackcoupe]

Originally Posted by G.M.

The relief valve ALWAYS leaks, there is a flat on one side that
always lets a small amount of oil on the timing gears. I like to
adjust the oil pressure with Castrol 20/50 oil and a mechanical
gauge screwed into where the gauge sender is. I use 1/8th inch
pipe as a shim on top of the spring, the hole in the pipe needs
to fit over the top end shaft of the valve. I start with a spacer
3/8" long. With the spark plugs out and a little oil in the cylinders
and the intake manifold off crank the engine with 12 volts. It will
spin fast enough to show you the TOP OIL PRESSURE you will
have driving down the road at 40 to 50 MPH. You can adjust the
pressure by changing the thickness of the shim to get the
maximum pressure you are going to get with the amount of engine
wear and the output pressure of the oil pump. The pump could also
have a relief valve with the same spring issues of the valley spring.
I built a fixture to spin the oil pump with a 1/2" electric drill so I
can tell if there is gear wear or clearance problem or the bypass
spring is weak. G.M.

wow! ok that's something I can try. I have already put a mechanical pressure gauge on the block so the spacers creating better pressure sounds like a great idea!
we've been flushing the motor w/marvel and 30 weight. 5w-30 ran through like water.
thank you for the response

ccBulligen

[Ken/Alabama]

Is this a new rebuild or is this something that just started happening? You have verified that the vent tube is installed so I'm beganing to wonder if something is going on with the oil pan gasket at the point where that part of the pan mates the block.

[TomT/Williamsburg]

Perhaps the 80 lb spring is too much? I use a 50 lb'er in my avatar and at speed I am at 48 lbs of oil pressure, at hot idle no less than 15 lbs.

I say this by virtue of the fact that changing to the 80 lb spring lessened the problem - just a thought and a cheap, quick try .... if it gets better again at least you can drive it ....

[Ken/Alabama]

Am I missing something here? �� I have re-read the original post and he said oil was pushing out of the vent in the oil pan. How does the oil pressure and the spring under cap for the timing gear have any affect on the vent? One other question I do have is the baffles inside the lifter valley in place?

[G.M.]

Originally Posted by Ken/Alabama

Am I missing something here? �� I have re-read the original post and he said oil was pushing out of the vent in the oil pan. How does the oil pressure and the spring under cap for the timing gear have any affect on the vent? One other question I do have is the baffles inside the lifter valley in place?

That's what I'm wondering?? Sounds more like pressure in the
crankcase. G.M.

[31blackcoupe]

Originally Posted by Ken/Alabama

Am I missing something here? �� I have re-read the original post and he said oil was pushing out of the vent in the oil pan. How does the oil pressure and the spring under cap for the timing gear have any affect on the vent? One other question I do have is the baffles inside the lifter valley in place?

sorry if my original post was confusing. the oil is coming out of the breather vent at the bottom front of the engine block next to the oil pan. not the oil pan itself.
thank for the response

[31blackcoupe]

Originally Posted by Ken/Alabama

Is this a new rebuild or is this something that just started happening? You have verified that the vent tube is installed so I'm beganing to wonder if something is going on with the oil pan gasket at the point where that part of the pan mates the block.

vent tube is installed and tight. purchased motor "as is", runs fine except oil coming from bottom breather (not oil pan). have not had oil pan off.
thanks for the reply

[31blackcoupe]

Originally Posted by G.M.

That's what I'm wondering?? Sounds more like pressure in the
crankcase. G.M.

again I apologize for not being more clear about where the oil is coming from. the leak is from the breather at the bottom of the engine in front, not anywhere on or in the oil pan.
thanks for the reply

[31blackcoupe]

Originally Posted by Ken/Alabama

Am I missing something here? �� I have re-read the original post and he said oil was pushing out of the vent in the oil pan. How does the oil pressure and the spring under cap for the timing gear have any affect on the vent? One other question I do have is the baffles inside the lifter valley in place?

yes the baffles in the lifter valley are in place.
thanks again

[Ken/Alabama]

Originally Posted by 31blackcoupe

sorry if my original post was confusing. the oil is coming out of the breather vent at the bottom front of the engine block next to the oil pan. not the oil pan itself.
thank for the response

Yes, That's what I'm not understanding. That vent passage is not open to the crankcase anywhere except at the top of the tube under the intake. Can't imagine that much oil going that high up then falling through. That's why I ask about the pan gasket.

[31blackcoupe]

Originally Posted by Ken/Alabama

Yes, That's what I'm not understanding. That vent passage is not open to the crankcase anywhere except at the top of the tube under the intake. Can't imagine that much oil going that high up then falling through. That's why I ask about the pan gasket.

yes confusing to us as well. the breather tube is tight, the oil filler tube is clear (no fuel pump rod or tube-even the cap+tube are removed for better air flow, electric fuel pump)sat for so long the sludge build up may be something? 80lb pressure at start up, no smoke, great compression, great response. getting better with each time we run oil + Marvel through it. may have to pull the pan thinking sludge is deposited in there n not moving. 20-30lb pressure when warm.
thanks again

[KGS]

[QUOTE= the oil filler tube is clear (no fuel pump rod or tube-even the cap+tube are removed for better air flow, electric fuel pump)[/QUOTE]

Sometimes you need to plug the hole where the fuel pump rod was removed. If there is high oil pressure blowing out through that hole, it may be throwing enough oil to get up to the vent at the front of the valve chamber. Ken

[JSeery]

On a 59a, the bushing for the fuel pump rod should not have a hole in it. But maybe it has been changed out to a later model one. I plug mine anyway.