Hot Rods Rear main seal still leaking!

The proper oil level should remain a constant distance from the pan rail no matter what the bottom pan configuration or capacity is . Follow that ?

Take a oil stock pan and fill it with 4 quarts of water.
Measure from the top down to the water line.

Take that measurement and transfer it to your oil pan and mark it.
Add water to the pan till you get to the mark you just made. How many quarts of water did it take to get to the mark. That's how much oil you want in the pan.
Mark the dip stick according to the water level.

BBC pan came in 4,5,6,7,8 quarts, then add for the filter, oil coolers, extra tall filter blah blah blah. The exact application will the exact same parts will have the exact oil capacity correct on the exact configuration dipstick. You have none of that so your on your own to figure it out. But it's easy - see first sentence

 

So how far below the shelf should the oil level be? That distance should be the same no matter the capacity of the pan right?

I think the point is mute. I drained 1/2 qt and just came back from a drive. First 3 miles were fine no leaks. After another 12 miles and the motor comes up to temp i have oil leaking from the rear of the pan by the rms, actually the bottom of the flange that captures the rms if that makes sense.

Not looking forward to taking the motor out again, especially with the march meet in 5 weeks.

Time to take a step back...

 

In my experience, most cars have 5 quart systems including the filter and heavier trucks and RVs have 8 quart systems including the filter. You likely have a pan for an 8 quart system. It appears that the level is not too high from the picture. It is strange that the oil drips after the engine is shut off as it appears that the level would be below the rear pan seal. Oil has to be sitting somewhere and running down. I suspect the oil is leaking out the back of the block and sitting between the block plate and the block. As others have said, there are plugs in the back of the block for oil to the lifters and the camshaft bearings. You could loosen the bell housing bolts a little, pry the plate back, run the engine and see if it drips while running if you don't want to take it all apart to look.

 

I now think the oil i was seeing earlier was generated while the motor was running but no way to tell now. Nothing leaking now while motor is not running and it didnt start leaking again till came up to temp


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The shelf is irreleveant as well as the shape or capacity of the pan at this point.
Do you follow me?
The oil level in relation to the oil pan rail (where the oil pan bolts go ) is what remains constant.
Do you follow me ?
Fill a STOCK car oil pan with 4 quarts and measure how far down the water level is. If I had a BBC pan around I'd do it. The only one I have is bolted to an engine

 

Maybe when welding the pan got tweaked, not sitting flat sealing at the main bearing cap.

 

Maybe im not understanding. Whether its the shelf (really a baffle) or the top of the pan they're both just a reference point right? In my case the baffle is the closer reference point.

I just got back from auto parts store. Picked up some valvoline 50w racing oil. Im going to put in 6 qts total. The heavier wieght may compensate for the looser fit at that #5 journal which was between 3-3.5 thosandths. The other bearing clearances around 2.5 thousandths. Im hoping that since it appears to leak when at operating temp (200 deg) the combination of thicker oil and reduced quantity will stop the leak.
If not it'll be time to pull the pan.


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When ever you check the oil in any vehicle with a dip stick, you're not measuring how much oil is in there - nope not at all. What you're measuring is how far down the oil level is from its designed and desired level considered full. That's why a reference point constant to the block and constant to the pan is what's important.


Your goal is to know where the top of the oil level should be in reference to the center line of the crank or pan rail or top of the pan. (All the same thing) Of that you have no idea right now. It really makes no difference at this point how many quarts It takes to reach the line just so there is enough oil to reach the line. Once you reach the line, then you know the quarts needed.

For example, On the bench -if I took what I knew for certain was a stock oil pan for the engine in question that was designed to hold 4 quarts plus 1 in the filter and I put 4 quarts in it then marked that level. This is important.

This is irrelevant parts.
Now I take a 55 gallon drum, cut 12 inches off of it, then cut a clearance for a tie rod, bell the bottom into the shape of an elephants foot, put 13 bricks inside of it, made an indent the shape of 4 large bananas, and 99 other stupid things then cut the bottom of the pan and weld the drum to the bottom of the oil pan, what is the correct amount of oil ? Would it matter if you knew from the 4th brick of 13 ? From The bananas, or which end of the bananas? All of it is completely irrelevant.

I don't know the answer either to how much oil it holds or needs but I can find out very easily,,, important parts.
First I know the distance from the crank CL, pan rail, top of pan EXACTLY how far down the oil should be. I know that because I did it first. You don't know but you could know, do it with a stock pan and transfer the distance into your custom pan.

I'd start filling the pan and Count the quarts going in the pan until the level reached the known distance from the top of the pan. Then I'd stick the dip stick in the pan and see where the thing landed on the marks. Hell I might even trim the tube if I could so the current marks were right.

When ever you check the oil in any vehicle with a dip stick, you're not measuring how much oil is in there - nope not at all. What you're measuring is how far down the oil level is from its designed and desired level considered full. That's why a reference point constant to the block and constant to the pan is what's important.

 

Hi Vicky, I think we're on the same page, my issue is I didnt measure the capacity prior to modifying or with the factory dipstick.
bottom line is I think I've got this licked. I replaced the oil with 6 qts of 50W and I just came back from a 15 mile drive with car up to operating temp for last 7 miles. I checked twice while at operating temp and no leaks. I'm planning on taking it to the track next Saturday and we'll just have to see how it goes. Oil pressure may have been a little higher than the lighter wieght oil by 5psi?...maybe.

Planning on going to Thompson speedway this year, I see your from Cleveland, hope our paths cross.

 

I think the engine is building crankcase pressure, eliminate the pcv and put a header crankcase evacuation kit on.