1963 390 FE Oil burning, right side

Good afternoon,

I need some ideas on where to look for the cause of an odd phenomenon. My 63 bird burns oil on the right side only with a full sump of oil. If I let the oil drop to a level of 1/2 to 1 qt low, the burning oils stops. It acts like bad oil seals---however, I have thoroughly checked them and they are good. All cylinders check at 190 compression. The engine was rebuilt approximately 10 years ago and the car sat in a collection rarely driven until I purchased it 1 year ago.

Any and all ideas will be appreciated----in the meantime, I will drive it with a reduced load of oil.

Thanks,
Howard Potter
Naples, FL
 

Hadderz

Well-Known Member
I got caught out with the wrong dipstick on a 67 mustang, but if you've drained and added the factory amount inc the filter, that's the most accurate. Then I'd look at if the PCV might be blocked/stuck then valve seals?
 
It has already been mentioned about the valve seals, that is really the first place to look.
Pull the valve cover and use an awl or small screwdriver to push the seals down. Sometimes they will ride up.
If those are good my next question is the plugs. Are they uniform or does one stand out?
You have done a compression check and that looks great.
So have you checked the vacuum?
Occasionally a manifold can have a vacuum leak on bottom. This most often occurs when the cork end gaskets are used. Especially after the block and heads have been milled.(they generally don't mill the manifold sealing surface) On the F/E series I use a bead of silicone only.
Good luck! Keep us posted.
 
Thanks for the inputs----is there a method to check via a vacuum gauge if there is a leak at the manifold gasket surface----if that is the case, why would the visible oil burning all but disappear when I let the oil level fall by 1/2 to 1 qt of oil?

By the way---I do not know my right from left---it is the LEFT side that exhibits the oil burn
 
Ok, warm up the car good. Remove a small vacuum line from the manifold behind the carb and hook up vacuum gauge. Start car and observe reading. Rev motor a couple of times and let idle. Does the gauge hold steady at idle or does it bounce? A bouncing gauge indicates a potential vacuum leak.
While you're investigating it is a good idea to check the oil drain back passages. A clogged drain can cause too much oil to build up and this can lead to consumption. I have seen the little foil covers from oil bottles in many engines.
 

Ward 57

Well-Known Member
Thanks for the inputs----is there a method to check via a vacuum gauge if there is a leak at the manifold gasket surface----if that is the case, why would the visible oil burning all but disappear when I let the oil level fall by 1/2 to 1 qt of oil?

By the way---I do not know my right from left---it is the LEFT side that exhibits the oil burn
I would surmise that if the oil burn decreases at a lower oil pan volume you have less volume and probably less pressure. I'd be hesitant to drive hard or long before you figure it out. It's running on reserve so don't dare stress it.
 

64ZCODE

Well-Known Member
Here's another possibility. One of more oil rings on the right side may be worn or broken, which would likely not affect cylinder compression. When the oil level in the sump is high, there is likely more oil splash on the cylinder walls from the motion of the crankshaft.
 

doug7740

Well-Known Member
Thanks for the inputs----is there a method to check via a vacuum gauge if there is a leak at the manifold gasket surface----
Vacuum testing is a quick way of telling the condition of the engine. Connect the vacuum gauge to the intake manifold port that is common to all cylinders. Manifold vacuum is highest while decelerating with the throttle closed and lowest at acceleration when the throttle is just opened.

With the engine at normal operating temperature; at idle, normal engine vacuum should be 18 to 22 inches of vacuum and the needle of the gauge should be steady.

As 74 Harley stated; a bouncing gauge indicates a potential vacuum leak. If your vacuum gauge needle isn’t steady at idle, a bouncing gauge would indicate weak valve springs or worn valve guides, while a drifting gauge needle would indicate a carburetor problem.

As I stated before, normal engine vacuum should be 18 to 22 inches. If your vacuum gauge reading is 3 to 9 inches lower than normal, that would indicate a vacuum leak.

Attached is a vacuum gauge reading chart that I use to give my students when I taught Automotive Technology.

doug7740
1955 Thunderbird Blue
 

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Ward 57

Well-Known Member
Ok, warm up the car good. Remove a small vacuum line from the manifold behind the carb and hook up vacuum gauge. Start car and observe reading. Rev motor a couple of times and let idle. Does the gauge hold steady at idle or does it bounce? A bouncing gauge indicates a potential vacuum leak.
While you're investigating it is a good idea to check the oil drain back passages. A clogged drain can cause too much oil to build up and this can lead to consumption. I have seen the little foil covers from oil bottles in many engines.
Never heard of that but I'm not surprised.
 
How do you know it is only one side of the motor? Oil wiper rings stuck will not alter compression when first driven but will later on when baked oil glaze forms on cylinder wall. Consumption goes down when oil level goes down because there is less splashing of oil up on cylinder wall. I have dumped a quart of Marvel Mystery Oil in gas and had good luck in the past on motors with stuck rings from sitting. Old method of dumping used not new transmission fluid in carb while running was another trick I have heard of. I would not recommend either of them on cars with cats on the exhaust.
 
Vacuum testing is a quick way of telling the condition of the engine. Connect the vacuum gauge to the intake manifold port that is common to all cylinders. Manifold vacuum is highest while decelerating with the throttle closed and lowest at acceleration when the throttle is just opened.

With the engine at normal operating temperature; at idle, normal engine vacuum should be 18 to 22 inches of vacuum and the needle of the gauge should be steady.

As 74 Harley stated; a bouncing gauge indicates a potential vacuum leak. If your vacuum gauge needle isn’t steady at idle, a bouncing gauge would indicate weak valve springs or worn valve guides, while a drifting gauge needle would indicate a carburetor problem.

As I stated before, normal engine vacuum should be 18 to 22 inches. If your vacuum gauge reading is 3 to 9 inches lower than normal, that would indicate a vacuum leak.

Attached is a vacuum gauge reading chart that I use to give my students when I taught Automotive Technology.

doug7740
1955 Thunderbird Blue
Thanks very much fo the information and the chart----I did run vacuum when I first got the car---but I've forgotten the results---I will run again and see. The oil burning acts like bad valve seals and because of the dampers, I cannot see them without removing the springs---BUT that does not explain the reduction in visible oil burning when the sump is 1/2 to 1 qt low. The only good thing is I am reducing the mosquito population as I drive around.
 
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