Oil Leaking On Headers at High RPM

[threewood]

The hits just keep on coming and I am about at my whits end. Got my vibration issue fixed so I go for a joy ride. Some spirited driving and a 5700 rpm shift later and there was a cloud of smoke following me.

Got home and took a peek. Oil had been dumping on the pass side header. Looked at the oil pressure switch, some oil around it so I tightened it and sealed it. There was plenty of oil on and around the filter so I pulled the filter inspected the adaptor which was tight. Put a new filter on, checked oil and went back out. Same thing.

Seems anything above 3k and it is squirting oil from an unknown location. There was oil covering the 727 bellhousing, the back half of the oil pan, center link, right side header, right side tortion bar.

I'm too mad to go out there right now. Where do I need to start? I have only the factory oil pressure gauge but could rig a pressure gauge to see where it is at.

New engine probably less than 5k on the rebuild (specs below). Has open breater on driver side cover, breather on pass side has a tube that runs down behind engine.

Could the rear main seal leak at high rpms and be fine just cruising around?

 

[Bigal75]

The oil sender on the back of the block? If so check it out more closely. They split and leak where they're pressed together. Been there done that. Oil everywhere and couldn't figure out where it was from.

 

[Cranky]

What are you using to vent the crankcase? PCV or other?

 

[HEMI-ITIS]

If it is dripping/spurting onto the exhaust,you should be able to see where it's burning.

 

[threewood]

What are you using to vent the crankcase? PCV or other?

Open breather on driver side, open breather with waste tube on pass.

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If it is dripping/spurting onto the exhaust,you should be able to see where it's burning.

I need to try again with the idle raised. Nothing above the oil filter, nothing to the front. I can just see the aftermath on the header and collector. Also across the bottom of the bellhousing, back bottom of yhe oil pan and the trans oil pan.

 

[Cranky]

Open breather on driver side, open breather with waste tube on pass.

Waste tube? Not sure of the term. The engine needs something that will pull some kind of vacuum on the crankcase besides letting it try to vent itself....

 

[kiwigtx]

Check the turkey pan under the intake. If you've ever back-fired the engine this pan will split - ask me how I know. :yes:
At high speed or high RPM, the oil will find a way to the top of the engine and leak out - then get blown back onto the exhaust. The big block engine make a lot of internal pressure and it looks for an easy escape route.

Easy way to check - pass a piece of rag under the intake and run from back to front - or front to back....whatever is most accessible. Use an old wire coat hanger or similar to grab the rag.

 

[threewood]

Waste tube? Not sure of the term. The engine needs something that will pull some kind of vacuum on the crankcase besides letting it try to vent itself....

It is a breather with a pipe that snakes down to the back of the engine. A vent of some sort, stock on the 318A motor. No pcv.

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Check the turkey pan under the intake. If you've ever back-fired the engine this pan will split - ask me how I know. :yes:
At high speed or high RPM, the oil will find a way to the top of the engine and leak out - then get blown back onto the exhaust. The big block engine make a lot of internal pressure and it looks for an easy escape route.

Easy way to check - pass a piece of rag under the intake and run from back to front - or front to back....whatever is most accessible. Use an old wire coat hanger or similar to grab the rag.

I wish I had a big block! This is on a 318A, no turkey pan.

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Here are some pics. Too hot still to start messing with but you get the gist. Again, 5k on the motor without oil leakage issue until today. I am hoping it is the adapter gasket for the oil filter. There is a good drip hanging off the filter so it probably came from above and the oil pan behind the filter is drippy with oil. If the rear main was leaking I don't see how it could get splashed up near the oil filter. Pressure switch is still bone dry, not coming from there.

What is the Felpro # for the round gasket?

 

[HEMI-ITIS]

Now after the engine cools off,run your fingers across the back of the intake and along the back of the valve cover. You need to figure out where it's leaking.


Now that I see the pic's,,,,,,,you need to look under the valve cover and see if it is running down the block.If everything is oil soaked,you need to degrease under there and go for a short blast at WOT and get back to the garage to see where it's leaking.

 

[kiwigtx]

OK, information is always KING. :hello2:

Is it possible that someone installed the rear main seal incorrectly - had that issue with a 360 once. Can't believe how someone got it wrong...but they did.

 

[threewood]

Now after the engine cools off,run your fingers across the back of the intake and along the back of the valve cover. You need to figure out where it's leaking.


Now that I see the pic's,,,,,,,you need to look under the valve cover and see if it is running down the block.If everything is oil soaked,you need to degrease under there and go for a short blast at WOT and get back to the garage to see where it's leaking.

I wiped everything down the last time and everything was coated so it didn't really help me. One item of note: the oil pan and bolts behind the filter were dripping with darker oil like it was dirty. I don't know much about the filters but could this mean filter/gasket leak?

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OK, information is always KING. :hello2:

Is it possible that someone installed the rear main seal incorrectly - had that issue with a 360 once. Can't believe how someone got it wrong...but they did.

Anything is possible. What would be the cause of it starting to leak at this point in time? Also, it is a rope type seal (1962 318A)

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Here are pics of the adapter and gasket, didn't look bad. Plate is flat. Gasket is not what I expected, kind of a hard material. Not rubber. It is .065" thick. While it is out, should I drill extra holes in the plate to aid in flow? If I am getting higher pressure at upper rpm could extra hole alleviate the problem of blowing by the gasket (if that is the source of the leak)? Anyone have a part number for replacement gasket?

 

[SlinktRR]

Oil filter gasket judging by the spray pattern. That is very close to the header tube and will get very hot, may warp and fail. Could try a more pliable gasket material and wrap the header at that spot to control the heat.

 

[2059]

Looks very familiar! and you're right it's very frustrating. Check the oil filter gasket issue mentioned earlier first. Had the same problem on the first Hemi rebuild caused by excessive crankcase pressure. (not sure why, maybe the rings haven't seated yet?) the reason I couldn't pin down the leak is because it was coming from EVERYWHERE!. Valve covers, Rear Valley cover gasket, etc. I agree with Cranky, you'll need some "vacuum" pulling on that crankcase. I solved the problem by installing two crankcase evac. tubes, one on each side. That draft tube is largely passive and wont help at all at low speed/high rpm conditions. Here's what I'm talking about and use this type setup. It's a little time consuming to install but once done, you should notice a significant difference.

http://www.summitracing.com/parts/aaf-all34145

 

[Cranky]

Ok, got the waste tube...also called draft tube or crankcase vent, spit tube and more lol. And the tube will be adequate enough do the job at low rpm. Heck, any kind of a vent will work at low rpm. Even my 97 Cummins powered pickup uses one from the factory. Been down the oily road before with a small block. Everything was fine with 2 breathers, one on each valve cover until it made a full rpm pass at the track shifting at 6200. So much for a nice clean engine bay! Hooked up a factory style PCV system and the oil downs stopped. It even blew the dip stick up a good 2 inches and pushed the front intake gasket out a bit. At high rpm, the engine will whip up a good amount of oil and will build a good amount of pressure in the crankcase (rings will never be a perfect seal against blow by) and if the crankcase doesn't have some help to evac the pressure, it'll push it out anywhere it can. I would go the simple route first with the factory PVC setup and if that doesn't stop it (I'm betting it will), then go with the Summit setup.

 

[threewood]

Oil filter gasket judging by the spray pattern. That is very close to the header tube and will get very hot, may warp and fail. Could try a more pliable gasket material and wrap the header at that spot to control the heat.

Do you mean the oil filter ADAPTER gasket? After it started leaking, I replaced the oil filter and had the same result.

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Looks very familiar! and you're right it's very frustrating. Check the oil filter gasket issue mentioned earlier first. Had the same problem on the first Hemi rebuild caused by excessive crankcase pressure. (not sure why, maybe the rings haven't seated yet?) the reason I couldn't pin down the leak is because it was coming from EVERYWHERE!. Valve covers, Rear Valley cover gasket, etc. I agree with Cranky, you'll need some "vacuum" pulling on that crankcase. I solved the problem by installing two crankcase evac. tubes, one on each side. That draft tube is largely passive and wont help at all at low speed/high rpm conditions. Here's what I'm talking about and use this type setup. It's a little time consuming to install but once done, you should notice a significant difference.

http://www.summitracing.com/parts/aaf-all34145

Good info! I think I will try to go the PCV route first as it should be easier to fabricate. The valve covers on the poly have a raised sleeve that the breathers push into so I need to figure out a mounting solution for the valve. I have a 1405 Eddy which has a port for pcv.

Looking at the summit kit, it has 2 pipes which get welded into the exhaust? And that pulls vacuum?

 

[Cranky]

Looking at the summit kit, it has 2 pipes which get welded into the exhaust? And that pulls vacuum?

Yup....the bungs are weld at an angle to the collectors about mid way. I've head a lot of people say that the system works better when you do not run mufflers....or at least use mufflers that create very little if any back pressure.

 

[threewood]

I am waiting until noon to pick up my new gasket from Autozone, Felpro # 70522. They are good at getting in special order parts fast. I have my pass side v cover rigged to accept a pcv valve. Used a brake cylinder grommet, looks like a baby bottle nipple lol but looks like it could be stock.

One thing I did observe....the adapter plate when in place without the gasket hit the center nub while the outer edge floated. I cannot believe this would be good at sealing so I used a large socket on my shop press and pressed the center in a bit. Now the outside ring contacts before the center. Should help.

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Yup....the bungs are weld at an angle to the collectors about mid way. I've head a lot of people say that the system works better when you do not run mufflers....or at least use mufflers that create very little if any back pressure.

I have mufflers but they are straight shot Dynomax UltraFlows, 2 1/2" duals. I will keep that setup in mind if I still have issues. Thanks!

 

[Bigal75]

Did you check the oil sending unit? How is oil going to get up there from a leaking filter?

 

[threewood]

Did you check the oil sending unit? How is oil going to get up there from a leaking filter?

Oil sending unit was a seperate, small leak. Tightened it and top end is dry.

Got the new gasket, new filter installed, pcv system added. Still leaking. At this point I am about 95% sure it is the rear main seal. The oil was just running off of the bell housing and transmission pan was coated. Some oil was even on the driver side header. 5% of me thinks it could be too much oil pressure but why only flow out the rear?

I need to pull the inspection cover and oil pan. I'm beginning to hate this.

 

[Bigal75]

I don't think it's too much oil pressure. I have 100 psi at idle cold.
Are you able to start the car and look around when it's running?
You're sure the oil isn't coming from up top?

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You say oil on the bell housing or coming from inside? Is it an auto? If so pull the inspection plate and you'll see if the oil is coming from the main seal. If the oil is on top of the housing then I would suspect something else.