63 Monza 900 - Oil From Dipstick?

[Wulf]

I am very lost. Seems to be oil coming out of dipstick, enough to make the car smoke pretty bad while driving. I replaced the PCV Valve and checked the hoses for any clogs so far.

I drove for about 20 mins and car was smoking badly and seemed to have lost alot of power? Very slow to accelerate.

I am very new to this and not really sure where to go from here. Any help or advice would be greatly appreciated!

[bbodie52]

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.

If oil is being forced out of the dipstick tube, it sounds like you either have a problem with excessive crankcase pressures caused by excessive blow-by that leaks past the pistons and piston rings into the crankcase, or you may have a problem with your Positive Crankcase Ventilation (PCV) system. The engine crankcase is a sealed chamber. It is normal for a certain amount of combustion chamber gases to escape past the piston rings and into the engine crankcase. Those fumes are expected and on 1963-1969 Corvair engines they are vented from the crankcase and drawn back into the intake system via a vacuum tube and a tube that connects to the air cleaner. This system is designed to properly ventilate the sealed crankcase during all engine operating conditions and speeds. If the PCV system becomes clogged, or if the piston rings and cylinders become excessively worn, the crankcase pressure buildup may exceed the ability of the PCV system to properly vent the engine crankcase. Under these circumstances the pressure buildup will seek a path out of the crankcase. The only path readily available is often the oil dipstick tube. As the pressure pushes its way through the oil dipstick tube, engine oil is often siphoned from the oil reservoir at the bottom of the crankcase and pushed up through the dipstick tube. A small volume of oil siphoned in this way would exit the top of the dipstick tube and likely drain back the outside of the engine and create a mess around the right exhaust manifold. If pressures become too great oil may be forced out of the dipstick tube at such a rate that it will be spraying around the engine compartment and making a mess in that area.

If the PCV valve is clean and the vacuum hose is properly connected to the engine vacuum balance tube, you may have symptoms that point to excessively worn pistons and piston rings. Normal combustion chamber pressures may be escaping past the pistons into the crankcase at an excessive rate, causing pressure buildup that is greater than can be handled by the PCV system. Verify that the oil level is not excessive by checking the dipstick to ensure that the oil is not over full. If oil level is OK and the PCV system is functioning properly, oil being pushed out of the dipstick often indicates a need for an engine overhaul to correct problems with worn pistons, rings, cylinders, etc. A compression test should be performed to confirm the mechanical condition of the engine.

You may need to perform a compression check of all cylinders to check the condition of the seal that should exist in each cylinder. A proper seal is affected by the condition of the pistons and cylinder walls, piston rings, intake and exhaust valves, and cylinder head gasket. If you find one or more cylinders that fails the compression test, a more advanced cylinder leak down test can be performed to try to determine the specific cause of the low cylinder pressure. Hopefully a simple cleaning and servicing of the PCV system will resolve your problem. A failure of a cylinder compression test and/or leak down test could point to the need for a more extensive engine overhaul or repair.

The Positive Crankcase Ventilation (PCV) system was designed by engineers to deal with crankcase ventilation requirements in a wide range of engine operating conditions — full throttle, closed throttle, partial throttle, high RPM, low RPM, and everything in-between. The baffle plate and vents, the PCV tube, the PCV valve or fixed vacuum orifice that is connected to the engine intake, and the PCV breather connected to the air cleaner, are all part of a dynamic system design that is intended to function continuously during all engine operating conditions.

When road draft tubes were used, they were simple unfiltered tubes that routed from the Corvair crankcase cover directly downward, where they vented through a hole in the sheet metal cover under the right side of the engine, adjacent to the oil pan. There was never a tee on it that connected via an orifice to manifold vacuum at that time. The first stage of Positive Crankcase Ventilation that appeared around 1963 utilized an appropriately-sized vent restriction (PCV valve design AC-CV584) that limited the amount of crankcase fumes and air that could be drawn into the vacuum balance tube that connected at the base of the carburetors to the intake manifold. This was essentially a "vacuum leak" that was engineered into the system to draw some of the crankcase fumes into the intake manifolds to be burned as they passed through the combustion chambers and ultimately out through the engine exhaust system.

Part of the main vent tube is ALSO CONNECTED TO THE AIR CLEANER. This allows those excess crankcase pressures that cannot be completely drawn through the PCV valve and into the intake manifold to be managed by instead having them drawn through the air cleaner assembly and into the carburetor intake throats. The secondary vent path into the air cleaner assembly allows for excess crankcase pressures that routinely occur at higher engine speeds and that would also routinely overwhelm the limitations of the PCV valve vent path. (This necessary connection also allows air that is filtered by the air cleaner air filter to access the engine crankcase, providing a balancing effect for the crankcase so that crankcase vacuum and pressure can be maintained at approximately normal atmospheric pressure). Without the connection to the air cleaner assembly, the sealed crankcase has no way to "breathe", because half of the normal PCV system design would have been omitted.

The fixed orifice only became a part of the PCV system in 1964-1969. The use of a fixed orifice was not a part of the 1964 system in Forward Control (FC) vehicles and in air conditioned cars, because of clearance limitations in the van and truck engine compartments and in cars equipped with air conditioning. Those vehicles retained the earlier design of the air cleaner assembly with its associated PCV valve design (AC-CV584).












The picture below shows accumulated sludge. Sludge was somewhat common in engines before PCV systems were introduced. Road draft tubes did not do a great job of removing contaminants and also added a lot of contamination to the air, which promoted problems with SMOG. Fumes in the engine crankcase would accumulate, and buildup would be found in the engine oil. Frequent oil and filter changes were necessary to minimize sludge accumulation, and in engines that were neglected the oil contaminants would develop into sludge that could be found throughout the crankcase and in the valve covers and valvetrain. These containment buildups in the engine would ultimately ruin the engine and reduce its lifespan. 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.

[Wulf]

Thank you for your help Brad. Ill check for some sludge. If i remove the oil filler cap I get alot of smoking from there once the engine has been under a load.

Ive got some input that it is most likely worn piston rings. Would you happen to have any info on putting new ones in or how difficult this task is?

Thank you agaain VERY much. I would be lost without these forums!

[azdave]

I would never open up an engine only for a re-ring job because you'll soon say "while it's apart I should have the heads done, and re-seal this and that, and check this...". Before you know it you have a whole rebuild going on (which it might need anyway). You can take shortcuts and only re-ring but anytime you pull the heads you have many things that could also come up like pulled head studs which is a major concern when removing the heads and torquing them back down.. Make 100% sure your PCV system is operating correctly before you do anything drastic. Some people will drop the oil pan and shorten the dipstick tube so that only air will come up the tube instead of oil.

Lots of ideas on the other forum too where you asked this same question.
http://corvaircenter.com/phorum/read.php?1,1086475

[bbodie52]

If you cannot find anything wrong with the normal crankcase ventilation system, you must assume that there is a problem with one or more cylinders. The first diagnostic step would be to remove the spark plugs and then perform a compression pressure test in each cylinder. The standard is 130 psi, with no more than 20 psi variation between cylinders. The procedure is outlined in the shop manual. Two types of compression testers are generally available, as shown below. The type with the flexible hose generally works better with Corvair engines, as it is easier to gain access to the spark plug holes with this type of tool.



Normally, a low cylinder pressure reading would be followed up with a cylinder leakdown test, which requires more-specialized testing equipment and an air compressor. This test can tell you if the low cylinder pressure is due to excessive piston blowby, a leaky intake or exhaust valve, or a problem with a cylinder head gasket. However, if the compression test points to one or more cylinders with abnormally low compression readings, that information coupled with already identified but unexplained excessive crankcase pressure buildup would likely indicate a piston or piston ring problem and the necessity of removing the cylinder head(s) to determine the cause and to make the necessary repairs.

Hopefully your problem is nothing more than a fault in the crankcase ventilation system, which would be relatively easy to repair. If it turns out to be one or more damaged pistons/rings or cylinder barrels the repair will be more time-consuming and costly.

Personally i don't believe in the concept of just re-ringing one or more cylinders. If the cylinder barrels and pistons/rings are worn out and in need of replacement, you are really looking at a complete engine overhaul to determine the condition of the rest of the engine. The extra steps involved will generally produce a much better, long lasting and rewarding outcome. The process can be a real confidence and knowledge builder, as well.

You would normally remove the engine and transaxle from the car, separate the engine from the differential, and then completely disassemble the engine for cleaning, inspection, and the replacement of worn parts. This might include a new camshaft, timing gear and hydraulic lifters (not always needed — you may decide to reuse these components (mark the lifters to reinstall them in the same locations they came out of to match the cam lobes they have worn-in on). But if the engine has accumulated a lot of mileage and years of use, i would recommend a new camshaft and aluminum timing gear — properly assembled by the vendor, like Clark's Corvair Parts. Proper installation of a new aluminum timing gear is a critical operation that must be done properly, and Clark's offers this service when you order the new components from them. New lifters should be installed with the new camshaft. The crankshaft must be carefully inspected, and if the journals measure OK, simply install matching bearing shells for proper clearance.It is possible to reuse pistons and simply hone the cylinder barrels, but if they are worn excessively, new pistons, machined cylinder barrels, and new rings may be on your agenda. Having the heads reconditioned at a good machine shop that can handle Corvair heads means a valve inspection and reground valves/valve seats and inspecting and reconditioining the valve guides. New valve springs are also a possibility. Of course new seals and gaskets through the engine will be needed. Reconditioning or upgrading the distributor (possibly to switch to a breakerless electronic ignition), new plug wires and spark plugs, and a carburetor rebuild are part of the equation. If the transmission is a manual transmission, an inspection and reconditioning of the clutch assembly is also part of the job.

I did my first Corvair engine overhaul on a 1963 Corvair 500 (Powerglide automatic) during my summer vacation in 1969 when I was sixteen. It was slow going and I learned a lot. My father provided the garage, tools, funding, and shop manuals, but he had been transferred by his employer from Northern California to Southern California, so I was pretty much on my own to learn the process of removing and overhauling an engine. If you are inclined to take on such a learning experience, you can download and read through the 1961 Corvair Shop Manual and the 1962-1963 supplement at no cost to get an overview of the work involved, using the following ...

The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader format at no cost. There is also a link that will help you to locate nearby CORSA (Corvair Society of America) club chapters. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts in Shelburne Falls, MA is the biggest and oldest Corvair supplier in the world. You will find a link that can provide you with a series of videos that amount to a tour of the Clark's Corvair Parts facilities. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

viewtopic.php?f=225&t=6007

If there is a CORSA club chapter near you, you might consider joining it to get to know other local Corvair owners, and discuss the issues you are having with your 1963. In addition to advice, you may even get offers of technical training and help to assist you in the project. Their knowledge of local machine shops and parts suppliers can also be invaluable.

I would like to encourage you to expand on your first post and tell us more about yourself, as well as about your Corvair. If you can provide your personal assessment of your mechanical skills and abilities, that would help a lot. Members of the Corvair Forum love to be helpful in assisting other Corvair owners with technical support and advice, but it helps a lot if we have some understanding of your technical background and mechanical abilities, your Corvair-related knowledge, etc. Helping us to know more about you will help us to write comments to you that are tailored to your needs and experience. Knowing your location can also be useful, as that information can sometimes suggest possibilities and options.

[bbodie52]

For more catalog info on the lower end, pistons, rings, cylinder barrels, etc. (10 pages)...

http://www.corvair.com/user-cgi/catalog ... ow_page=21