what is the purpose of the oil dipper at back of motor?

[JD4430]

Please excuse my ignorance but I am a beginner and I want to learn. I have a 1930 Model AA farm truck. My oil pan was removed to clean all of the gunk out. I noticed at the back of the motor there is an arm extending downward. I am thinking this is what is called the "oil dipper". What is its function? When I put the oil pan back on is the dipper supposed to extend below the dipper tray?

[alexiskai]

Originally Posted by JD4430

Please excuse my ignorance but I am a beginner and I want to learn. I have a 1930 Model AA farm truck. My oil pan was removed to clean all of the gunk out. I noticed at the back of the motor there is an arm extending downward. I am thinking this is what is called the "oil dipper". What is its function? When I put the oil pan back on is the dipper supposed to extend below the dipper tray?

This is not a dipper, it’s a drain tube that drains excess oil from the rear main bearing.

[J Franklin]

The things called dippers are on the bottom of the connecting rods, FYI.

[old31]

The dippers pick up oil in the removable tray or trough that sits inside, on top of the oil pan.

[Bruce of MN]

Do yourself a favor and get and read this book:

https://www.snydersantiqueauto.com/p...0031&cat=41621

[nkaminar]

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Most people think that it is important for the drain tube to extend into the oil in the bottom of the pan. The reasoning is that this prevents pressure in the pan from pushing the oil from draining from the rear of the rear bearing and thereby causing the oil to drip out onto the ground.

[Bruce of MN]

Originally Posted by nkaminar

Most people think that it is important for the drain tube to extend into the oil in the bottom of the pan. The reasoning is that this prevents pressure in the pan from preventing the oil from draining from the rear of the rear bearing and thereby causing the oil to drip out onto the ground.

I would think that the inside of the tube would see the pan air pressure plus the depth of the oil above the tube outlet.

[old ugly]

you obviously have the oil pan off, make sure that tube and the gallery that it screws into are clean, no dead gunk in there.

that drain tube is effective only if some idiot has not restricted the oil filler tube with steel wool or other materials in an attempt to stop a blow by problem. that is when crankcase pressure build and force oil out the rear main.

[JD4430]

To all I really appreciate your responses. Thankyou very much and yes I have already ordered the Les Andrews book.

[Synchro909]

Originally Posted by JD4430

To all I really appreciate your responses. Thankyou very much and yes I have already ordered the Les Andrews book.

Keep your wits about you when using that book. It contains many errors but generally, it has lots of good info.

[JD4430]

Thankyou Synchro909 for that good advice. I really appreciate this Ford Barn Discussion site. I have a long learning curve ahead of me which I am looking forward to as I progress.

[Benson]

While oil pan is removed OR any time oil pan is removed it is a good idea to clean the screen inside the oil pump. If you do not know how long it has been since it was last done.

In the late 20s and mid 1930s many 2 to 5 year old low mileage engines were damaged from lack of oil caused by dirty filter screens in oil pumps. This is why regular oil changes with detergent oil are recommended.

This is even more important if car is driven for short and frequent trips where it never gets warmed up for any length of time.

Many screens get clogged up when fiber timing gears fail and the pieces clog screen .

When something like a timing gear fails do not just replace parts ... do yourself a favor and Find out WHY the failure happened.

The Service Bulletins cover many of cases like this!

[old31]

JD, what's great is that you sound like you want to learn. Keep it up.

[rotorwrench]

Crankcase pressure is one of those things that increases over time with piston ring wear. When blow by gets higher than normal, it can try to push pressure out at any point of loss. Seals & bearings wear over time as well. The rear main is a drain point that is very close to an exit point. To keep the drain flow from being forced out the back, they put the tube in there to exit the oil back where it's supposed to go. Since the tube is below the oil level, crankcase air pressure can't get in there easily. It would have to go through the bearing which is already flowing some oil and tends to slow any air pressure down. The air pressure follows the path of least resistance which is the oil cap vent on the oil fill tube.

[JD4430]

Wow this is good stuff! Thankyou again to all of you