Oil Dripping from Vent Pipe - 1962 Monza Spyder

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SeamusNZ
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Joined: Fri Sep 16, 2016 3:11 pm

Oil Dripping from Vent Pipe - 1962 Monza Spyder

Post by SeamusNZ »

Hi all,

I have a small amount of annoying oil that drips from the vent pipe under the engine. I have also noticed quite a bit of smoke/fumes coming from the vent pipe, particularly when the engine gets hot and it is idling. I have just fitted new rings etc.

Any ideas what is causing this and how to I rectify it.

Kind regards...

SeamusNZ :helpsos:
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wbabst
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Location: Lake Elsinore, California

Re: Oil Dripping from Vent Pipe - 1962 Monza Spyder

Post by wbabst »

You say you just put in new rings...how many miles have you put on the engine since new rings. You will have more blow by then usual until the rings seat in the cylinder.
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SeamusNZ
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Re: Oil Dripping from Vent Pipe - 1962 Monza Spyder

Post by SeamusNZ »

I have done around 200 miles on the new rings......
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bbodie52
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Re: Oil Dripping from Vent Pipe - 1962 Monza Spyder

Post by bbodie52 »

Have you tried running a compression check, and perhaps considered a leakdown test on each cylinder to help verify an adequate seal in each cylinder?

The Corvair crankcase is sealed. The only ventilation on 1960-1962 Corvairs is the road draft tube.

Image
Crankcase Cover and Vent.jpg
The road draft tube (or positive crankcase ventilation - PCV system) is connected to the engine crankcase top cover and vent baffle plate. The baffle vent allows fumes to escape via the tube, but normally blocks oil spray from reaching the breather tube.

1963 and later Corvairs were fitted with a PCV system that used engine vacuum to remove crankcase fumes and pressure. This was more efficient than the older road draft tube, which was a simple opening that vented the crankcase. A moving vehicle would assist, to some extent, with evacuating the fumes by creating a "draft" to help "vacuum" the pressure buildup, but the PCV system was more effective.
Turbocharged Engine PCV System.jpg
Image

A cylinder leak down test is a more advanced diagnostic procedure, and little more difficult to perform, because it requires some fabricated plumbing or a special test instrument, and a large capacity air compressor. Each cylinder to be tested is set at Top Dead Center (TDC) on the compression stroke (both valves closed). External air pressure is applied through the spark plug hole, and the percentage of leakage is evaluated. The source of the leakage (intake valve, exhaust valve, cylinder head gasket, or piston/cylinder seal) can be determined using an automotive stethoscope to listen for the leakage path (intake manifold, exhaust manifold, or crankcase). This test is performed on each cylinder, to determine the mechanical seal and condition of each cylinder. A video demonstration of this process (in this case, using a Volkswagen engine) is shown below.



There are many leak down testers available on Amazon.com. An example is shown below...

Image

OTC 5609 Cylinder Leakage Tester Kit

4½ Stars out of 5 with 307 customer reviews | 23 answered questions
List Price: $109.95
Price: $69.42 & FREE Shipping.

Prices ranged from $33.54 to $99.99 with 10 LEAK DOWN units listed.

:link: http://www.amazon.com/s/ref=sr_st_revie ... eview-rank

A decent mechanic's stethoscope can be had for about $15.00...

Image

Also helps to locate noisy idler bearings, blower bearings, etc.

OF COURSE, A PURCHASE OR A RENTAL WILL DO YOU NO GOOD IF YOU DON'T HAVE ACCESS TO A DECENT AIR COMPRESSOR WITH ADEQUATE CAPACITY.

These tests may help you with diagnostic testing to determine if you have a problem with one or more cylinders or the piston ring seal.
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
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