1961 Monza Coupe

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Unca
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1961 Monza Coupe

Unread post by Unca » Sun Feb 11, 2018 5:52 pm

Howdy folks, Unca is the name. I just picked myself up a 1961 Monza Coupe, I found receipts in the glove box where a full tune up had been purchased for it back in 1997 from the good old National Auto Parts Association, I checked under the cap and sure enough... points, rotor, condenser and cap itself... all new. I got out the 5/8" socket and pulled the 4 easy plugs and they all looked great and the wires felt and looked good as well. Dip stick shows good clean oil right in the middle of the lines, not a trace of antifreeze in the oil ;) JK. The old battery is also from 97 so today I picked up a new one (51R) and it turns over and has compression. I hook up a temporary fuel line to the pump, primed the carbs and got no combustion. An old plug and wire lets let me see I have no spark and the coil was to blame, I throw in a good used replacement I had on the shelf and it fired right up, I'd say a good start for my new car.

This is my first Corvair but I have had a good few other cars now including air cooled boxers so I look forward to this new project!

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bbodie52
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Re: 1961 Monza Coupe

Unread post by bbodie52 » Sun Feb 11, 2018 8:56 pm

:welcome2: :wave: :wave: Welcome to the Corvair Forum!

1961 was a transitional year when Chevrolet switched distributor designs from that used in the 1960-61 Corvair to a redesign that was introduced in late 1961 and continued to the end of Corvair production in 1969. The two distributors are shown in the picture below. The early design has a distributor cap that is a clip-on design, while the later distributor uses a distributor cap that is held in place with screws. Internally the early distributor has a centrifugal advance mechanism that is mounted above the points, with a large rotor that completely covers the centrifugal advance. The later design relocated the centrifugal advance to a location under the ignition points and breaker plate.

Which distributor do you have in your 1961 Corvair?

The distributor design on the left was introduced in late 1961, and is was found on all 1962-1969 Corvairs.
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The carburetors used in 1961 were also unique, because they were the only carburetors that used a manual choke system. In 1962 an automatic choke system was introduced, and remained in use through the end of Corvair production in 1969.

The crankcase ventilation systwm used in 1960-1962 was a simple road draft tube. A Positive Crankcase Ventilation system was substituted in 1963.

:dontknow: I would like to encourage you to expand on your earlier posts 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 specific location is also useful, because knowing where you live can sometimes suggest possibilities.

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. While the Corvair Forum can be very helpful as you work on your Corvair, having local friends and contacts in your region who are knowledgeable about the Corvair can also be very helpful. These family-friendly CORSA chapters often offer picnics, group scenic drives, technical training and assistance, car shows, and competition events that can greatly enhance your enjoyment of Corvair ownership. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts 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. I think you will be amazed at the quality of the reproduction components they offer — particularly the interior carpeting and re-upholstery items. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

:link: viewtopic.php?f=225&t=6007

:welcome:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

Unca
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Re: 1961 Monza Coupe

Unread post by Unca » Tue Feb 13, 2018 3:28 pm

Thanks for the welcome Brad. My 61 has the later style distributor and does in fact have manual choke. As for my Corvair knowledge... well I know about as much as any car guy that has not previously owned a Corvair would know. I am handy with a wrench and consider myself pretty well versed in the mechanics of cars and how / why they work... or more times than not, why they don't work.

You say: "The crankcase ventilation system used in 1960-1962 was a simple road draft tube. A Positive Crankcase Ventilation system was substituted in 1963."
Could you explain more because I was actually about to do some research on this. Again this is my first Corvair and I have had it now only 4 days. Sunday evening, after a new battery I and temporary fuel line it ran but was blowing oil out the dipstick tube and my first thought was crankcase ventilation and possibly a stuck PCV valve but I had not gotten any further than simply thinking about it as it was late and I had to prepare for work.

I picked the car up as a project because I was looking for something fun and different to have as a daily driver too and from work, about 15 to 25 min each way on 55 mph roads. I enjoy cars that have a story to tell and stand out as unique and the corvair has always done that. I found this one advertised local as having a good solid body and floor pan rot, engine/trans condition unknown so I went to look at it. I grabbed the belt and pulled and the crank was free so I took a gamble on it. I'm not sure still what exactly I want to do with it as far as fit and finish but for now I will just be going through and fixing systems and getting the car back road worthy... the spirit of the car will come with time.

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bbodie52
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Re: 1961 Monza Coupe

Unread post by bbodie52 » Tue Feb 13, 2018 11:57 pm

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.

1962 and earlier Corvair engines did not have a PCV system. Like most earlier engines, they were fitted instead with a simple road draft tube.
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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).

All PCV systems have connection between the main vent tube and the air cleaner, which is necessary for proper crankcase ventilation. With the use of custom individual air cleaners, you can replicate the portion of the PCV system that is missing by installing a connection to the right air cleaner. The custom air cleaner can be modified to provide a hose connection at its base.

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The illustration below shows the proper configuration for the turbocharged Corvair PCV system. The illustration was taken from the Corvair shop manual.

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The turbocharged Corvair PCV system is functionally the same as that used on non-turbocharged, normally aspirated Corvairs. A short tube from the metered orifice is connected directly to the turbocharger intake at the base of the carburetor. This would be the correct connection point since it would always be a source of unpressurized intake vacuum. The other portion of the PCV tube connects to the air cleaner, as it does on the normally aspirated Corvairs.

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:chevy:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

Unca
Posts: 3
Joined: Sun Feb 11, 2018 12:59 pm

Re: 1961 Monza Coupe

Unread post by Unca » Wed Feb 14, 2018 5:42 pm

Okay, I will check and see if the draft tubes are clear. The PO had put on a set of ill fit Mr.Gasket air cleaners because the bottoms of the stock air cleaners were rusted out, he simply capped the line that comes up from the back of the carbs in the middle. I will be going back to factory air cleaner setup at some point but for the time being I will put a little rubber hose on this and a motorcycle style crank case breather filter on the hose.

I will let you know if this stops the oil from coming out the dip stick.

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