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oil usage

69fire 69fire
New User | Posts: 29 | Joined: 05/13
Posted: 05/27/13
03:34 PM

I just had a Pontiac 455 stroker motor built to 468, Comp cams Hydraulic roller cam, eagle crank and rods, Edelbrock torker II, edelbrock 800 thunder series, iron heads, new pistons etc. spent a fortune, by a reputable engine shop in Clawson Michigan for my 69 Firebird, car runs real well, strong, BUT I am going through a lot of Brad Penn oil. about 100 miles uses a Quart, NO smoke anywhere no leaks anywhere, pcv rattles so I assume that's good, valve covers have internal baffles all new. any suggestions would greatly help, I hate to have the engine pulled and torn down because it runs so darn good. anyone have any advice??  

gtojack1366 gtojack1366
Guru | Posts: 1223 | Joined: 11/09
Posted: 05/28/13
05:02 AM

If it's not leaking it has to be burning the oil .Maybe it's only leaking when you drive it ? Do you have a crankcase vent tube to the air breather ?  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 05/28/13
08:22 AM


I see you are a new member, welcome to the site.

I am going through a lot of Brad Penn oil. about 100 miles uses a Quart, NO smoke anywhere

How many miles are on it?

Are you using synthetic oil and if so when did you start busing it.

If it’s burning oil it is smoking at least just lightly guaranteed and should probably smoke most under acceleration.  If it is not burning oil it is leaking.

My neighbors new engine smoked slightly and used that much oil, turned out the rings didn't seal.


no leaks anywhere,

Some leaks can be very hard to see even if they are big if the oil. I had a gasket come out of the rear of and intake. The car was leaking 1 qt every 100 miles and it was hard to find. If it is not leaking it is burning oil.

You can also take it to an air conditioning shop and have them put dye in it. Drive it for a day or so then take it back and have them check it with their uv lite and special glasses. This process works xlnt for finding leaks.


pcv rattles so I assume that's good,

Has no affect on burning or leaking oil.


I hate to have the engine pulled and torn down because it runs so darn good.

Oh, we hear ya.


anyone have any advice??  

Do you have a warranty?

If you have a warranty I would take it to the A/C shop first and do the dye test [since the shop may not have this dye kit]. Have the A/C shop write down results on a receipt then at least you can prove to yourself and the engine shop whether it is leaking or not.

If it is NOT leaking the alternative cause is obvious, it is burning oil. This is caused by rings that are not sealing properly and/or valve guides leaking.

A quick “inexact” test to see if the rings are not properly sealing is to take the pcv and oil fill cap off, then plug pvc hole on valve cover, then rev the motor a couple times and see if smoke comes out the oil fill hole then hold throttle at around 2000 and see if smoke comes out then hold hand approximately 1 ½” above hole and feel how much pressure comes out the hole. Slight pressure is ok heavy pressure bad rings.

Valves guides leak because they are either knurled and have either umbrella seals or no seals instead of spring type seals [like pc’s] or guides are excessively worn and do not have the rubber spring type seals.

SPARK PLUGS – If they are even the least bit damp and remain damp after laying for a few minutes you are burning oil from rings and/or guides.

TAIL PIPE – If your car is kept in a dry warm [above 50 degrees] area then stick your finger in the pipe and feel if it is bone dry or damp. If it is damp it is oil.

KNURLED GUIDES - If the original guides were knurled it is because the were worn and you should have been informed before they knurled them. I never run knurled guides.

RINGS NOT SEATING - If it is determined the rings are not properly sealing the most important thing to find out is why so it does not happen again, once is enough. Some of the reasons rings don't seat are the folloewing

1. Synthetic oil was used during break in or any time before the first 500 miles
or so.

2. Break in was done improperly.

3. Cylinder hone was wrong grit for rings.

4. Rings are Chrome [highly unlikely].

5. Rings were damaged during installation in cylinder [this can occur if a "sleeve" type installer is not used for installation.

6. The oil ring end gaps are lined up.    


Let us know what you find.  

69fire 69fire
New User | Posts: 29 | Joined: 05/13
Posted: 05/28/13
10:43 AM

There is no tube from valve cover to air cleaner, just breather caps on both sides with baffles under the valve covers, thankyou for All your replies, the Engine shop says it would be smoking a lot if it were rings. So I have to look into trying to find any leaks or they may be able to see about that, too, I don't know if that brad penn stuff is synthetic or not, I have to look into that also. There is only 200 miles or so on the new motor.  

69fire 69fire
New User | Posts: 29 | Joined: 05/13
Posted: 05/28/13
11:16 AM

The pcv is in the valley pan front of engine to a hose to front of edelbrock carb  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 05/28/13
11:40 AM


I don't know if that brad penn stuff is synthetic or not, I have to look into that also.

I looked at the brad penn oils and would not use the multi weight oils. I would use Valvoline VR1 20/50 .
ALL multi weight brad penn oils are partially synthetic.

All straight single weight brad penn oils are straight mineral oil [no synthetic]



There is only 200 miles or so on the new motor.  

Ok thanks for the info, same suggestions as gtojack and my first post, it’s a leak and/or burning oil.


There is no tube from valve cover to air cleaner, just breather caps on both sides with baffles under the valve covers,

This will not affect the breather smoke or pressure test I suggested whatsoever. This test takes 60 seconds. The tail pipe test takes 5 seconds.


the Engine shop says it would be smoking a lot if it were rings.

Typically but it’s not always easy to see. If they are reputable as you say they are I would think they would have given you at least some kind of warranty even on a high performance build up to around 450 hp warranty. I always did.

Does this mean you are not going to do my 60 seconds worth of tests at all?

The plug test takes around 15 minutes but as mentioned if ANY are even REMOTELY damp after laying out of the cylinder for more than a couple minutes your burning oil 110% positively guaranteed no matter if it leaks or does NOT smoke etc.

The plugs should be as dry as T rex.


So I have to look into trying to find any leaks or they may be able to see about that, too,

Same warranty comment as above.

Any part that looks remotely wet can be a MAJOR leak at cruising speed.

Check floor pans and OUTSIDE and INSIDE of rear bumper for signs of oil.

Wipe it with a white paper towel, engine oil will appear lite brown/green.  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 05/28/13
11:47 AM


Ok the plot thickens. Just curious is this the original mounting location for the pcv on your year etc?

"The pcv is in the valley pan front of engine to a hose to front of edelbrock carb"

Thanks for the updated info. See if there is a lot of oil on the end of the pcv?

Stick your finger in the pcv mounting hole and rev the motor at 2500 for a few seconds. If your finger is wet with oil your pcv is sucking up oil from the valley. Irregardless, take the pcv hose off at the carb and see if inside of hose is wet. If it is then it is definitely sucking oil.

This means that at least part of your problem MIGHT be that your pcv is mounted in the wrong location OR your ring blowby is so great that it's blowing oil all over the inside of your motor and blasting it into the pcv.

If you have a pcv hole in a valve cover that is covered by a baffle then try that and drive for 100 miles and re-check oil.  

waynep712222 waynep712222
Enthusiast | Posts: 310 | Joined: 03/13
Posted: 05/28/13
12:00 PM

check the flow rate of the PCV valve.. to see if its undersized or oversized...  flow wise..

engine warmed up.. idling.... tachometer hooked up.   when you pinch off the PCV hose... you should find the engine RPMs drop from 50 to 70 RPMs..

more than likely... you will find that the RPMs drop more than 70 when you pinch off the hose.. and that might be the reason for the excessive oil consumption..  

this 50 to 70 RPM took me a LONG TIME to find these specs... its not widely known..

PCV valve vendors have started sorting PCV valves by external shape.. not flow.. so they provide ONE size for each shape.. reducing part numbers..   there used to be a small round tool that you placed over the breather opening and watched the ball move around to measure the flow rate to know if the PCV was too big or too small for the engine..  i have not seen one of those in decades..  

69fire 69fire
New User | Posts: 29 | Joined: 05/13
Posted: 05/28/13
12:50 PM

Thankyou all for the help, I will try everything you guys suggested as soon as I can and let you know what happens, I sure appreciate all your advice. I am going to try a different pcv valve also.  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 05/28/13
02:14 PM


"Thankyou all for the help, I will try everything you guys suggested as soon as I can and let you know what happens, I sure appreciate all your advice. I am going to try a different pcv valve also."

I would try the other stuff first, here's why based on my experience others experiences may be different. A pcv valve that sucks more air than a stock one might suck up a LITTLE more ATOMIZED oil but it is NOT going to suck up much more oil at all if your rings are good. It can suck more than than 300 cfm but as long as there is no oil "showers" splashing around directly in front of the hole in the pcv it will suck mainly AIR. The only way for it to suck a QUART of oil every 100 miles would basically be to SUBMERGE it into the oil in the oil pan pan OR have ring blowby AND be stuck in the unbaffled valley pan like it is now instead of a baffled hole that would prevent "showers" of oil from getting into it.

Do you have a windage tray? If you don't then installing one will NOT fix your problem but it will be better all around especially if you run it at high rpm's a lot.

OIL - I would also change to full mineral right away like I mentioned. If it is the rings not seated you might get lucky and they will seat better after a while. Oils with synthetics may leak past some gaskets a little easier also due to the synthetics properties.

PCV VALVE = Just curious, how are you going to determine if on flows less or more than yours if that is what you want to determine? I think there used to be a chart for this but Waynepp may know for sure. I there is you might need to go to a NAPA store to find one.  

waynep712222 waynep712222
Enthusiast | Posts: 310 | Joined: 03/13
Posted: 05/28/13
09:31 PM

PCV VALVE = Just curious, how are you going to determine if on flows less or more than yours if that is what you want to determine? I think there used to be a chart for this but Waynepp may know for sure. I there is you might need to go to a NAPA store to find one.  

there is NO flow chart anywhere as far as i can tell..

i researched this even on the PCV designer/manufacturers web sites .. took weeks of spare time..

i totally agree that 100 miles is more than likely another issue... rings that are NOT sealing properly... oil leaks.. leaking valve stem seals.. excessive valve guide clearance.. too tight a fit on the guide liners and one got pulled down around the head of the valve..   there is a reason that the guide liners are cut off with a flanged tool.. to leave a little lip..

but i have seen people think 100 miles is like 300 or 400 miles...

the PINCH OFF the PCV hose test with a digital TACH hooked up is a 5 minute perhaps 10 minute test that you only have to open the hood for..

50 to 70 RPM drop...

let me explain why... back in the mid 90s.. when i ran a head department at a local engine rebuilder a 390 ford kept coming back and coming back for excessive oil consumption..  400 miles per quart.. this guy drove to tiajuana several times a week so he knew how much oil was used per hundred miles.. after we rebuilt the engine several times.. including different blocks and heads.. same oil consumption..  another shop prior to us  had done 2 or 3 warrantee rebuilds also ..  i got him to bring the truck complete for me to examine..  it was clean enough to eat off the engine..  if you liked licking chrome and engine enamel..  i ask when it all started burning oil.. just after he had done a complete tune up.. yes.. including the PCV valve.. i sent him to ford for a factory replacement in either a sealed ford box or a sealed motorcraft box.. not just a loose PCV tossed on the counter..  that fixed it.. the opening ID in the bad PCV was probably 11/32   where the replacement from ford was probably 1/4" perhaps 7 mm..   i was not aware of the 50 to 70 RPM drop back then..  i was wishing i had a PCV flow tester..  

waynep712222 waynep712222
Enthusiast | Posts: 310 | Joined: 03/13
Posted: 05/28/13
09:35 PM

this is an FYI..

The Positive Crankcase Ventilation (PCV) system reduces blowby emissions from the engine. About 20% of the total hydrocarbon (HC) emissions produced by a vehicle are blowby emissions from gases that get past the piston rings and enter the crankcase. The higher the mileage on the engine and the greater the wear on the piston rings and cylinders, the greater the blowby into the crankcase.

Before PCV was invented, blowby vapors were simply vented to the atmosphere through a "road draft tube" that ran from a vent hole in a valve cover or valley cover down toward the ground.

In 1961, the first PCV systems appeared on California cars. The PCV system used intake vacuum to siphon blowby vapors back into the intake manifold. This allowed the HC to be re-burned and eliminated blowby vapors as a source of pollution.

The system proved to be so effective that "open" PCV systems were added to most cars nationwide in 1963. An open PCV system draws air in through a mesh filter inside the oil filler cap or a breather on a valve cover. The flow of fresh air through the crankcase helped pull moisture out of the oil to extended oil life and reduce sludge. The only drawback to these early open PCV systems was that blowby vapors could still backup at high engine speed and loads, and escape into the atmosphere through the oil filler cap or valve cover breather.

In 1968, "closed" PCV systems were added to most cars. The breather inlet was relocated inside the air cleaner housing so if pressure backed up it would overflow into the air cleaner and be sucked down the carburetor. No vapors would escape into the atmosphere.


Typical PCV system.

The major component in the PCV system is the PCV valve, a simple spring-loaded valve with a sliding pintle inside. The pintle is tapered like a bullet so it will increase or decrease airflow depending on its position inside the valve housing. The movement of the pintle up and down changes the orifice opening to regulate the volume of air passing through the PCV valve.

The PCV valve is typically located in a valve cover or the intake valley, and usually fits into a rubber grommet. The location of the valve allows it to pull vapors from inside the engine without sucking oil from the crankcase (baffles inside the valve cover or valley cover deflect and help separate droplets of oil from the blowby vapors).

A hose connects the top of the PCV valve to a vacuum port on the throttle body, carburetor or intake manifold. This allows the vapors to be siphoned directly into the engine without gumming up the throttle body or carburetor.

Because the PCV system pulls air and blowby gases into the intake manifold, it has the same effect on the air/fuel mixture as a vacuum leak. This is compensated for by the calibration of the carburetor or fuel injection system. Consequently, the PCV system has no net effect on fuel economy, emissions or engine performance -- provided everything is working correctly.

WARNING: Removing or disconnecting the PCV system in an attempt to improve engine performance gains nothing, and is illegal. EPA rules prohibit tampering with any emission control device. Disabling or disconnecting the PCV system can also allow moisture to accumulate in the crankcase, which will reduce oil life and promote the formation of engine-damaging sludge.


The flow rate of a PCV valve is calibrated for a specific engine application. For the system to function normally, therefore, the PCV valve must adjust the flow rate as operating conditions change.

When the engine is off, the spring inside the valve pushes the pintle shut to seal the crankcase and prevent the escape of any residual vapors into the atmosphere.

When the engine starts, vacuum in the intake manifold pulls on the pintle and sucks the PCV valve open. The pintle is pulled up against the spring and moves to its highest position. But the tapered shape of the pintle does not allow maximum flow in this position. Instead, it restricts flow so the engine will idle smoothly.

The same thing happens during deceleration when intake vacuum is high. The pintle is pulled all the way up to reduce flow and minimize the effect of blowby on decel emissions.

When the engine is cruising under light load and at part throttle, there is less intake vacuum and less pull on the pintle. This allows the pintle to slide down to a mid-range position and allow more airflow.

Under high load or hard acceleration conditions, intake vacuum drops even more, allowing the spring inside the PCV valve to push the pintle valve even lower to its maximum flow position. If blowby pressure builds up faster than the PCV system can handle it, the excess pressure flows back through the breather hose to the air cleaner and is sucked back into the engine and burned.

In the event of an engine backfire, the sudden rise in pressure inside the intake manifold blows back through the PCV hose and slams the pintle shut. This prevents the flame from traveling back through PCV valve and possibly igniting fuel vapors inside the crankcase.


Because the PCV system is relatively simple and requires minimal maintenance, it is often overlooked. The common replacement interval for many PCV valves is 50,000 miles, yet many engines have never had the PCV valve replaced. Many late model owners' manuals do not even have a recommended replacement interval listed for the PCV valve. The manual may only suggest "inspecting" the system periodically.

On many 2002 and newer vehicles with OBD II, the OBD II system monitors the PCV system and checks the flow rate once during each drive cycle. But on older OBD II and OBD I systems, the PCV system is NOT monitored. So a problem with the PCV system on a pre-2002 vehicle probably won't turn on the MIL (malfunction indicator lamp) or set a diagnostic trouble code (DTC).

PCV valves can last a long time, but they may eventually wear out or clog -- especially if the vehicle owner neglects regular oil changes, and sludge builds up in the crankcase. The same sludge and oil varnish that gums up the engine can also plug up the PCV valve.


The most common problem that afflicts PCV systems is a plugged up PCV valve. An accumulation of fuel and oil varnish deposits and/or sludge inside the valve can restrict or even block the flow of vapors through the valve. A restricted or plugged PCV valve cannot pull moisture and blowby vapors out of the crankcase. This can cause engine-damaging sludge to form, and a backup of pressure that may force oil to leak past gaskets and seals. The loss of airflow through the valve can also cause the air/fuel mixture to run richer than normal, increasing fuel consumption and emissions. The same thing can happen if the pintle inside the PCV valve sticks shut.

If the pintle inside the PCV valve sticks open, or the spring breaks, the PCV valve may flow too much air and lean out the idle mixture. This may cause a rough idle, hard starting and/or lean misfire (which increases emissions and wastes fuel). The same thing can happen if the hose that connects the valve to the throttle body, carburetor or intake manifold pulls loose, cracks, or leaks. A loose or leaky hose allows "un-metered" air to enter the engine and upset the fuel mixture, especially at idle where the idle mixture is most sensitive to vacuum leaks.

On late model vehicles with computer engine controls, the engine management system will detect any changes in the air/fuel mixture and compensate by increasing or decreasing short term and long term fuel trim (STFT and LTFT). Small corrections cause no problems, but large corrections (more than 10 to 15 points negative or positive) will typically set a lean or rich DTC and turn on the MIL.

Problems can also occur if someone installs the wrong PCV valve for the application. As we said earlier, the flow rate of the PCV valve is calibrated for a specific engine application. Two valves that appear to be identical on the outside (same diameter and hose fittings) may have different pintle valves and springs inside, giving them very different flow rates. A PCV valve that flows too much air will lean the air/fuel mixture, while one that flows too little will richen the mixture and increase the risk of sludge buildup in the crankcase.

Watch out for cheap replacement PCV valves. They may not flow the same as the OEM PCV valve. Quality brand name replacement PCV valves are calibrated exactly the same as the original valves, and are designed to provide long-lasting, trouble-free performance.


There are a number of ways to check a PCV valve:

1. Remove the valve and shake it. If it rattles, it means the pintle inside is not stuck and the valve should flow air. But there's no way to know if the spring is weak or broken, or if a buildup of varnish and deposits inside the valve is restricting flow.

2. Check for vacuum by holding your finger over the end of the valve while the engine is idling. This test tells you if vacuum is reaching the valve, but not if the valve is flowing properly. If you don't feel vacuum, it means the valve or hose is plugged and needs to be replaced.

3. Use a flow tester to check the performance of the valve. This method is the best because it tests both vacuum and air flow.


The volume of air that is pulled from the crankcase by the PCV system is important because it takes a certain amount of airflow to remove the blowby vapors and moisture. But too much airflow can upset the air/fuel mixture in the engine. So to check airflow, you can do any of the following:

Pinch or block off the vacuum hose to the PCV valve with the engine idling at operating temperature. The engine idle rpm should typically drop about 50 to 80 rpm before the idle speed corrects itself (or you can disconnect the idle speed control motor so it won't affect idle speed during this test). If there is no change in idle speed, check the PCV valve, hose and breather tube for a restriction or blockage. A greater change would indicate too much airflow through the PCV valve. Check the part number on the PCV valve to see if it is the correct one for the engine. The wrong valve may flow too much air. If there is no part number, replace the valve with a new one (which meets OEM specifications) and test again.

Measure the amount of vacuum in the crankcase. With the engine at normal operating temperature, block off the PCV breather tube or vent to the engine (usually the hose that runs from the air cleaner housing to the valve cover on the engine). Pull out the dipstick and connect a vacuum-pressure gauge to the dipstick tube. A typical PCV system should be pulling about 1 to 3 inches of vacuum in the crankcase at idle. If you see a significantly higher vacuum reading, the intake manifold gasket is probably leaking and pulling vacuum on the crankcase (replace the leaky intake manifold gasket). If you see no vacuum, or find a buildup of pressure in the crankcase, the PCV system is plugged or is not pulling enough air through the crankcase to get rid of the blowby vapors.

NOTE: If the engine has a leaky oil pan, valve cover or intake manifold gasket leak, or leaky crankshaft seals, it will not be able to develop much vacuum in the crankcase because it is pulling in outside air (which is also unfiltered and can further contaminate the oil).

To find a crankcase air leak, you can lightly pressurize (no more than 1 to 3 psi) the crankcase with shop air via the dipstick tube or oil filler cap or breather after blocking all the other vents. Do not use any more air pressure than this or you may create leaks where there were no leaks before. Then use a spray bottle to squirt soapy water around the gasket seams and seals. If you see bubbles, you have found an air leak (replace the gasket or seal as needed).

A smoke machine also works great for finding crankcase leaks as well as vacuum leaks. A smoke machine generates a smoke-like vapor by heating mineral oil. The mist can then fed into the intake manifold to check for intake manifold vacuum leaks, or into the crankcase to check for internal engine air leaks. Any leaks will allow the smoke to escape and you will see the smoke on the outside of the engine.


When replacing a PCV valve, make sure the replacement valve is the same as the original. External appearances can be misleading because valves that look the same on the outside may be calibrated differently inside. If the replacement valve does not have the same flow characteristics as the original, it may upset emissions and cause driveability problems.

The PCV hose that connects the PCV valve to the engine should also be replaced when the valve is changed. Use hose that is approved for PCV use only.

NOTE: Can't find your PCV valve? Some engines do not have a PCV valve, but use a crankcase ventilation system with a fixed orifice oil/vapor separator. The separator functions similar to a PCV valve, but there is no movable pintle or spring inside. The separator is simply a small box with some baffles inside and a calibrated hole that allows intake vacuum to pull the blowby vapors back into the intake manifold. Like a PCV valve, the separator can plug up with varnish and sludge, causing driveability and emissions problems.  

69fire 69fire
New User | Posts: 29 | Joined: 05/13
Posted: 07/21/13
04:04 PM

I was out of town and couldn't play with the car,got back and  I found out the oil is getting through the PCV valve which is in the valley pan, so I moved it to the valve cover still plumbed to front of carb, drove it over the weekend and (still losing OIL!) ugh! The shop that built the engine claims I need an oil separator, but I don't understand how that would keep the engine from losing oil, I couldn't find an explanation on how they work on line but I did see several for sale Frown  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 07/21/13
06:08 PM

"valve covers have internal baffles all new."

Is there a shield/baffle under the pcv so oil is not sprayed directly on it?

If so then it is my opinion that it should be torn down at this point and checked out.

If your pcv is properly shielded I don't think you should require an oil separator ie. band aid.  

Guru | Posts: 981 | Joined: 07/11
Posted: 07/22/13
08:25 AM

do you have a stock valley pan ?

what kind of rings did you use ?

what heads did you use ?

i was always told not to use synthetic oil until the rings were broke in 3000 miles to be safe. if you have chrome ring it will take longer than cast rings.

synthetic oil is too slick to let the ring scuff and break in.

i had the same problem with 2 different chevy motors. i used the same new set of world product s/r torquer heads on both motors with the same results. around town they would use 1 quart to a 100 miles on the interstate 1 quart to 200 miles. they both run great and the only time i could see the smoke was at night with lights behind me.

a friend has a machine shop he says to go out on a road with very little traffic run the vehical in 2 gear to keep the speed lower. run the motor up to 4500 or 5000 rpms then let off and let the motor drag the vehical back down to 2000 rpms. repeat this 10 to 15 times being careful not to over heat the motor.  
76 455/4spd TRANS AM

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