Help! Crank case pressure and oil pan leak??

I'm struggling with my new 500cid low deck stroker moror. I have a big oil pan leak from the front right corner and in the area of the rear main seal retainer. The Engine is equipped with a Milodoon Road race pan (part# 31580) and a windage tray. Frist thing I checked was if it leaked from the rear main seal but nothing comes out that way.
I have checked alignment and height of both front timing cover and rear mail seal retainer and that seem to be ok. I have used gaskets from Superformance two times now, once dry and once with small amount of High temp RTV where the timing cover meets the block and the same with the rear seal retainer. The pan is not warped and is 100% flat. As soon as the engine gets warm and gets reved above 3000rpm it starts leaking.
I'm running an open air filter style valve cover breathers on both vale covers but it still shows signs of crank case pressure with the deep stick raising out of it's tube. When I rev the hot engine without the breather I feel a slight pressure coming out of the breather grommet in the valve cover. The engine is freshly built professionally so I'm doubtful to piston ring blow by.

The oil leak is driving me crazy and I wonder if there is anything I could I have missed out? I consider trying to set it up with a vacuum pump, thoughts on that for a street motor?

A "slight" pressure is ok, but it sounds like you have too much blow-by if the dip stick tube is venting with the valve covers vented also. I would run a leak-down test next. Then maybe put a few miles on it and run the test again to see if there are any changes. Excessive blow-by could just be because the motor is new. A pan oil leak would occur all the time - although more excessive at higher RPM.

Concider a better breather set up,or better than that,,,,,,an electric vacume pump to relieive the crank case pressure.

It isn't unusual for big stroker motors to have a lot of crankcase pressure. Even if the rings have sealed up the bottoms of the pistons are pumping a lot more air in a stroker than they did in a stock engine.

One the dyno I usually use large #12 AN breathers on each valve cover. If the oil pan is restrictive then the air doesn't have anywhere to go and it builds up pressure. Pushing out the dipstick is a sure sign of a lot of crankcase pressure.

You can measure the blow by with the engine running just to see how much you have. You can also do a leak down test and a compression test if you think the rings haven't sealed up.

I run a electric air pump on mine out of a S-10 pick-up.

New motors may take a while for the rings to seal up well Did the block have a torque plate on it when honed? If not it may take longer for the rings to seat On my 511 and 518 C.I. 400 stroker motors I ended up with two PCV and two breathers, one each on both valve covers

Before you start looking at a crankcase vacuum system, verify you don't have a blow-by problem. With both valve covers vented, you should not be blowing the dip stick out of the tube @ 3K, even on a big incher.

Andy knows more than most, So I read his post and would tend to put a lot of weight in his words. With that said, enough blow by to push the dipstick out of the tube, coupled with RPM related oil leaks at the pan gasket, do not seem to be a good signs to me. Considering 500 cubes in a lowdeck generally means fairly short pistons, I'd be tempted to pull it and ask the builder to tear it down and take a real good look at the rings & skirts for evidence of anything unusual that could have happened upon initial start or break-in. ???.... your choice may vary.

Good luck! and keep us posted.

Having an intake vent and a PVC valve on both covers would just vent the area directly below the covers. The idea is to pull outside air from the valve cover with the intake vent, through the crankcase and out the PVC valve on the opposite valve cover using manifold vacuum.

I would think excessive blowby is your problem.

Is this a race only car or a street driven car ? Ron

it sounds like you have too much blow-by

X2

In this months issue of engine professional there is a good article on an adjustable p.v.c. M/E Wagner makes an adjustable valve that looks good. You might give them a try.

Thanks a lot for sharing knowledge! I will do a proper leak down test to check blow by. With two open air filter style breathers that have no resistance when I blow through them I doubt that I do not have proper enough crank case ventilation. I guess if all cylinders is within 10-15% leak down I have to go down the path of installing a vacuum pump.
This car / engine are only street driven is there anything I need to consider regarding vacuum pump choice or installation?

My 63 is a 99% street car and I just ran these vented breathers as the hose just runs to the back of the eng in case they would spit a little oil it would not go on the valve covers. But it does not vent any oil out of the valve cover breathers as I dont have much blowby. And since my car is mostly a street car I went back to a PCV system for the street. It pulls enough vacum to work the PCV valve. And when I go racing I hook both breathers back up since the PCV dont vent the crankcase much at wide open throttle. The PCV system works nice on a street car pulling any excess crankcase vapors out and burning them in the eng combustion chambers. Dont have any eng pics with the PCV hooked up yet. Gotta take a few soon. Ron

Check the breathers first... see if you can blow
through them... I bought a pair of chrome Summit
ones that I could barely get air through... I pulled
part of the stuffing out and bent the loovers open more
(blow from the oil side)

What is your static compression ratio? If you have detonation due to too high a compression ratio for fuel octane and air temp you'll get a whole bunch of crankcase pressure from that too. Or that is the 'experts' evaluation/guess to my former motor Hard/expensive lesson learned. I have a Milodon 31151 pan as well but does the 31580 have a divider/seal plate between the bottom of the engine crankcase and pan top? I wonder about the pistons pushing air against that pan plate? Have a brand new vacuum pump assy waiting on new 493" motor (with lower compression) and new header combo.

Are you certain that your RR oil pan flange is not dimpled or otherwise distorted? I've this same pan and found that torquing to recommended 15 pounds will grossly distort this flimsy/poorly designed flange.

I've posted before photos of my own little fix. If pan flange is damaged you will first require surgery to repair,,,hopefully successful. Once damaged and repaired, the metal has been compromised and will distort easier.

Used 1 inch wide by 1/8 inch thick steel stock, available at any hardware store.

Resolved my issues and all is well.

A major side benefit is with proper torquing, I am not required to use any silicone goop,,,I do use a bit at rear main seal retainer for insurance,,,makes for a much simpler oil pan RR next time.

I am aware that someone supplies a gasket with steel inserts or some such design at the bolt holes to help eliminate this distortion. I know available for Chevy(in fact I think factory built uses such), have not checked for Mopar.

Nice job. I like those.

Installed in car.

that happened to me when i removed my PCV valve. started blowing oil out the front right corner of the oil pan. put the PCV back in and it stopped.

On my Milodon #30930 7-Qt low profile pan, the pan curves down right after the bolt holes, and with me using the BCR stud girdle, the inner side part where the pan/girdle studs go was seeing oil, and the oil would drip down the oil pan studs. The outside of the oil pan sealed fine. I was able to fix the leaks by just putting some RTV around the studs, under the nuts holding the oil pan on.

It sounds like you may have a different problem, but may be worth checking if it looks like the oil is dripping from the pan bolts?

Did a leak down test on warm engine this weekend and all 8 where in the 6-10% leak down range so i guess that is not the problem.

Any toughts on running a vacuum pump on a street motor?

If you have a good baffle then it wouldnt be a issue.. but
if you dont.. do you feel like stopping every 5 miles to
pour the oil back in the engine from the catch can... you
need to find the base problem

I'm a little late to the game here, sorry

Unless your crankcase is experiencing some extreme pressure you should not be leaking between the oil pan/gasket/timing cover/seal retainer and I doubt that to be the case because, as stated, the rear main seal is dry and no mentions of leaks anywhere else.

I suspect your choice, application or method of using RTV sealer for the lack of sealing ability.

1) Use Permatex Ultra Black or equivalent.

2) Remove all traces of oil and apply an 1/8" BEAD to the areas of concern. Do Not spread sealant with your finger.

3) Install oil pan and gasket. Tighten bolts just snug enough to disperse sealant. Do Not allow sealer to skin over.

4) After 12-24 hours apply full torque to the fasteners.

5) Fill with oil, start and check for leaks.

Thanks,I appreciate your support

Make sure your oil pan and windage tray are not hitting the rear main cap studs/nuts if you are using main studs. They can hit just enough to keep the pan from completely pulling down on the block rail.

Make sure that the welds on sides of the windage tray doesn’t interfere. Install it with all the bolts but leave out the gaskets and have a look.

I had to do some grinding and welding on my tray to make it work, Mega block with Milodon #30930 pan and #32005 tray.

Impossible, that cannot happen!

I do not have a interference issue with the windage tray and I do not use studs on the mail. Like I have mentioned before I have tried many times now to seal this up with different gaskets with Würth Super RTV Silicone between all layers (pan gskets and tray) Been trying without any silicone, with only small amounts in suspected areas. I've been checking for a flat pan rail and windage tray and everything have been washed down with brake cleaner before assmbly and offcourse checking for holes / cracks in the pan.

Could the angle of the engine cause the leak in the rear? Running a TKO 600 transmission and that makes the engine being tilted more that normal towards the firewall.

Again, you are missing something. Bolts too long and bottoming out before full torque can be applied to the oil pan gasket?

You have either;
A) A component issue
or
B) An installation issue

The angle of the motor has nothing to do with a leak. Please, re-read my suggestion for proper installation of the Superformance gasket.

Key points...... Quality RTV sealer on the joints and across rear seal retainer, apply in bead form, do not spread out with your finger and do not allow it to skin over before installation.

I'm using the mopar performance pan bolts with the litte blue treadlocking compound on them and they are not bootomig out.
I will reorder a set of your gaskets and try again with a 1/8" bead of RTV silicone between the timing comer/ rear main seal retainer and the block. I guess I do the same between the pan and the Gasket. I think it's the 5th time I pull the pan this summer.....

I would agree with A or B if it wasn't for C = "dip stick blows out of the hole"( original post). He needs to get a definitive answer on crank case pressure FIRST. Lots of good suggestions on this thread and if the OP has done them all?, it leads back to a crank case pressure issue. Couple things the OP could try; 1.Start the engine up with both valve covers vented to the atmosphere. Just let it idle until it gets up to operating temp. Still got leaks? I would lean towards A or B. 2. Over fill it with oil until you are sure the oil level is above the pan rails on all sides and front and rear ( level the motor ). Let it sit that way over night. Got leaks in the same places? Again, I would be more apt to lean towards A or B.

The OP is running open element breathers.....


I have also seen dipsticks that fit very loose.
Not saying he does or does not have a blow-by issue.

Either way, the OP would need to have some severe crankcase pressure to blow past a properly sealed oil pan/gasket, especially a BB Mopar. And with no mention of leaks from other areas it keeps leading me back to improper installation or component issue but my eyes are not what they used to be.... can't see Norway from here anymore

I'm sure you are right about the Norway thing.