Ford poured rear bearing

[Chuck Sea/Tac]

Does anyone have pictures, or drawings of the specs of the rear main, in the block. Specifically, was the forward parting line open into the engine, or was it closed like the other bearings? I’ve seen pouring both ways. TIA

[SAJ]

Chuck, I cannot recall the pics, but I think an open groove will spill the pressure from the dynamic hydraulic wedge that is necessary for separation of the surfaces.
Thinking about that I recall finding an open rear main groove in our Tudor. I obtained some babbitt puddling stick and used a soldering iron to block and then hand-scrape the bearing back to the picture Herman Khonke (RIP) posted years ago.
Vince Falter has good pics on his Web site too.
Sa
SAJ in NZ

[Gene F]

Also, since it has that tube in the back, I'd think that the area should be closed.

[Modelacoupe3]

[QUOTE][/QUOTE
See attached photos . The rear bearing pictured was poured by Ford in 1930. The engine / car had 53,000 original miles on this bearing .

[BRENT in 10-uh-C]

Originally Posted by Chuck Sea/Tac

Does anyone have pictures, or drawings of the specs of the rear main, in the block. Specifically, was the forward parting line open into the engine, or was it closed like the other bearings? I’ve seen pouring both ways. TIA

On my engine prints, the oil groove basically travels from one hole in the block for locking the casting to the opposite side hole on the opposite end of the journal. It does not end at the end of the bearing, but stops approximately 3/8" from the end. The print calls for the depth of the oil groove to be 1/32" - 3/64", and the width to be 3/32".

[hazelhoff]

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Oil grooves really are a NO GO area. If you can, avoid applying them ! 1930-ties engineering mistake !

[rotorwrench]

They were not intended to exit the bearing surface. They always need to fall short of the edges or unnecessary leak down will result. They best lubricate the bearing if they are confined to the bearing surface only. There is enough leakage out the ends without adding more easy pathways.

[katy]

Originally Posted by Chuck Sea/Tac

Does anyone have pictures, or drawings of the specs of the rear main, in the block. Specifically, was the forward parting line open into the engine, or was it closed like the other bearings? I’ve seen pouring both ways. TIA

What exactly are you calling "the forward parting line"?

[Chuck Sea/Tac]

The parting line is where the cap and block bearings mate up. Forward is towards the front of engine. See modelAcoupe3’s pictures. Thanks everyone!

[ursus]

Originally Posted by rotorwrench

They were not intended to exit the bearing surface. They always need to fall short of the edges or unnecessary leak down will result. They best lubricate the bearing if they are confined to the bearing surface only. There is enough leakage out the ends without adding more easy pathways.

On the Model B rear main, Ford made the oil grooves in the form of an "X" and extended the grooves to the forward end and down the thrust face, thus creating an open pathway to the sump. I wonder if this was because the bearing was now pressurized, albeit at a low pressure.

I have only seen this on original engines produced by Ford. Subsequently rebuilt engines had bearing grooves cut in the manner of the Model A bearings. Some rebuilders even did away with the grooves altogether but retained the wells at the parting line.

[BRENT in 10-uh-C]

Originally Posted by hazelhoff

Oil grooves really are a NO GO area. If you can, avoid applying them ! 1930-ties engineering mistake !

Nonsense! The oil grooves were solely intended to be a passage way for the oil to be transferred from the Oil Pipe to the Oil Well located at the parting lines where the Cap meets the Block. This ensured the width of the crankshaft journal pin was lubricated enough where the micro-scratches in the pin's finish were to carry the layer of oil onto the bearing surface.

The biggest issue that causes bearing failures is people (-i.e.: rebuilders) have trouble redoing something just like Ford engineers specified. The irony is the Ford engineer's design generally lasted for 50,000+ miles of service yet when the rebuilders do it their way, premature failures happen almost immediately. Leave that groove out and see what the longevity is like too.