Hot Rods Rear main seal still leaking!

Hey,
A month or so ago i posted that my rms was leaking and included pics of a trashed #5 main journal bearing. I think i got that sorted out put the motor together and took it out for sone hard launches yesterday. Afterwards i came home and parked car in driveway on an incline...botyom line is there was oil dripping from main seal after about an hour.
Crap.
Before starting motor I put 7.5 qts of oil in and it still reads low by half a qt. Im using standard size wix filter. I modified the pan to clear the drag link (see pic) effectively reducing oil pan capacity but still reads low on the stick.
So heres my question, if you look at the attached photo and imagine the oil up to the bottom of the stick does it seem the oil level is to high in relation to the rms or the little shelf thats part of the pan? Anyone have a sense of where oil should be in relation to the shelf?



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As im looking at the pics i realize theyre at the wrong angle and dont include the rms.
BTW oil pressure 25 at idle 60-70 driving around, nearer to 80 when first starting.
I drained a qt today but havent restarted the motor. The drained oil looked good but its only got 20 miles and 4 good 1/4 mile runs on it.



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First thing... You need a longer bolt in the pitman arm... Doesn't look like it reaches the nylon in the locknut.

Seen it before... Did you put the rear main seal in with the lip facing away from the flywheel.. both halves? Mr. gasket used to make a double lip silicone rear seal.. they may still and others might. Worth the investment!!

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If you have the pan off, why not put 7 qts of water in it and see where it comes on the dipstick. Then add the angle that the pan sits at in the car and see where the oil is. You may see what your problem is then.

 

agreed, a longer bolt is needed. RMS oreintation is correct though

 

i put in 7 qts and the level comes up to the the point on the dipstick thats halfway between "add" and the bottom of the stick. I should've mentioned that the dip stick and tube are not orginal equipment...thats part of my problem.
if you think about it though I think I shouldve reduced the 7 quarts by the amount in a standard filter right? that would've brought the level down on the stick some as well.

 

I have seen it on tranny’s that have been swapped with units from the wreckers

Wrong did stick so it’s calibrated wrong to the application and you end up over filling it

Find out what the actual spec it for the oil required in the engine and oil required in the filter

7.5 quarts plus the filter and your still low sounds like a lot, even more so with the pan modified

 

The most important thing is for the pickup to be about 1/4" off the bottom of the pan. It looks like a modified pickup - so that is super important. What was the capacity of the pan before you modified it? I would start there - account for the size/shape of what you cut out of it (simple math) and come up with the correct amount to fill it with. Usually the amount stated assumes you have an empty filter.

 

my pickup is 1/4" from bottom of the pan, I verified that with clay before and after welding it to the tab you see in the pic. I didnt check capacity of the pan before modifying it, but without the right dip stick I'm not sure how much water to fill it with before Im at the right level (for example is "full" a half inch below the tray or is it 1/2" above it?). But if i knew where the proper oil level should be in relation to that shelf or tray in the picture, then I could figure out how much oil I should be running. I'm assuming the oil level should be below the shelf is that a correct assumption? be interesting if someone had an oil pan with correct dip stick and could share where "full" is in relation to the shelf.

 

seems like a lot to me too. I'm really hoping it's just a matter of the motor being overfilled.

 

With the pan off and 7 qts of liquid in it, where does the level come in relation to the rear seal? Measure how far the crank comes down below the pan rail and see if the crank is hitting the oil in the pan. If so reduce the amount of oil in pan. As I said before, allow for the angle of the pan when installed in the car in all calculations.

 

Looks to me like the notch in the pan cost you near a quart in capacity so if you're still putting in the same amount of oil, you'll be a quart over.

 

the problem is the pan is still on the motor in the car. I guess I can estimate from the outside the height of the shelf inside the pan from the pictures and the indents on the sides of the pan. and I have a good idea where the oil comes up on the stick when I'm at 7 qts. from that I can estimate where the height of the oil is in relation to the RMS.

 

so would a quart over capacity result in leaking from the RMS?? I guess thats the question that needs to be answered before I go to far down this road right?

 

10 quarts maybe, but not one. You gotta think... If it is dripping long after the motor is shut off, not likely the rear main. In fact it would leak like a sieve while it is running because of pressurized oil from the rear main bearing.
Look at the main cap real close where the seal sits... I have seen a couple of caps that had gaps allowing the seal to not be supported well.

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How are you set up for crankcase ventilation? PCV system? Breathers in the valve covers? Vented oil fill cap? Excessive crankcase pressure will try to find a way out anywhere it can.

 

Is this a stock oil pan you trimmed down? If you cut that much off a stock pan it would no longer be a standard 5 at. Pan. Stock pans most times are for 5 qts. with a filter. I must be missing something here. Way I read your two qts over stock with a filter and you have trimmed off a qts worth of pan. This looks like 3 qts over to me. .?????

 

Not something i'd considered. Breather in one valve cover with oil fill cap. Other side pcv valve plumbed to bottom of rear carb.



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Yep stock pan. When i put 7 qts water into it (while it was on my kitchen table) the oil came up to the mark shown on the dip stick. The mark is definitely below the add oil mark.
The pan came off a motor i'd gotten out of an rv. So i assumed 7 qts. The dip stick and tube was probably something i got from summit during the build.


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When did it start leaking and are you positive it's the rear main seal?...I once had a smallblock Chevy racing engine with top end oil restrictors screwed into the rear cam galley holes that were leaking and running down the back of the block and dripping off of the rear main cap...

 

Are you sure it's not the welch plug at the back of the cam, or the threaded plugs in the back of the block above the cam? I had the welch plug at the back of the cam on straight 8 engine left out by an engine builder. I didn't catch it and replaced the rear main seal 3 times before finding the welch plug missing.

 

#1 What did the pan come off of?

#2 How much oil did the engine hold that the pan came off of?

#3 Did any stock oil pans hold 7qrts ?

You all ready know the dipstick is wrong for the motor, so don't use it for a gauge till you know what amount of oil the pan holds. Adjust the marks on the stick after the correct amount of oil is added. See question #1 and #2.

 

Looking at the first photos, I think his oil level is about right where the stick is marked. The oil level should be just below the baffle in the pan, which it would be. I say put some oil dye in it, fire it up until you see a drip, shut it down and then use a blacklight to pinpoint where the leak is coming from. Auto supplies sell a blacklight that looks like a ball point pen that works great for that.

 

Just fill it with 5 quarts and drive it, I bet your leak goes away. Then change the markings on your dip stick.

 

they all leak

 

Just a suggestion, better get a front bracket on that starter or a rear main leak could be the least of your problems. BBC's are known to snap the starter mounting boss's off and then you'll have to resort to having your buddy's push start you every time or get a new block.

 

Cant be 100% sure unless i pull the motor out remove tranny and scattershield and take a look. If i can be sure its not caused by overfilling then that would be next step


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Back of the motor is covered by block saver plate part of scatter shield.


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You may end up pulling all of off...

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No, the rear main oil seal has nothing to do with the oil in the pan. It has everything to do with keeping oil in the the crank and the last bearing. The RMS seals the crank to the inside of the bearing cap and block.

The oil pan seal may leak if it's over full but that gasket should contain the oil. The oil pan gasket seals between the oil pan and the Outside of the rear main bearing cap.

In the area of the leak you have 2 potential sources, the oil pan gasket to bearing cap and the rear main seal. Literally just fractions of an inch away from each other.

The orange ring would not see oil from the pan,
the groove on top of the cap holds the gasket that provides the seal for oil in the pan.