Timing procedure 64, 110

[river_side]

When timing my 64, manual transmission, 110
do I disconnect and plug the vacuum advance?
Also, set at what timing?
I will probably be running regular gas most of the time.
Thanks

[Jerry Whitt]

Remove the hose to the vacuum advance. Adjust the timing. Then reattach the hose. With the engine running, move the throttle and watch the vacuum advance to make sure it moves the timing. Sometimes the vacuum advance does not work. This test will confirm.

[river_side]

OK, thanks, what should the timing be with the vacuum hose disconnected from the distributer?

[terribleted]

you can find that info in the 64 shop manual. http://www.corvair.org/chapters/corvana ... .php#C95RP

[bbodie52]

This tune-up chart is from the 1965 Corvair Chassis Shop Manual. The specifications on it also apply to the 1964 110 hp engine. I have also attached a copy of the 1964 Supplement - Chevrolet Corvair Shop Manual - Section 7 - Engine Tune-Up to guide you.

The timing range of 12° - 16° BTDC gives you some variation to tune for optimum performance for your engine and driving conditions. With low-octane Regular gas your best bet is likely to be on the low side (12°) to prevent detonation (pinging) under acceleration, when driving up a long grade or in a heavily-loaded vehicle, and during hot weather conditions.






Watching the video presentations below helps to provide insight and understanding about proper sequencing of the tuneup steps and procedures. Skipping around can insert obstacles and problems with getting the engine properly tuned.

Tuning the Corvair Engine — Part 1



Tuning The Corvair Engine — Part 2

The vacuum tube connection for the distributor vacuum advance is always the vertical tube on the Rochester carburetor. It is only exposed to engine vacuum once the throttle begins to open. With the engine idling the throttle is almost fully closed, so very little engine vacuum will reach the vacuum advance on the distributor. But just to make certain that the vacuum advance mechanism is not impacting the base timing setting, standard practice is to disconnect the vacuum hose from the distributor and plug it when checking/adjusting the base timing. The engine idle speed should also be less than 700 RPM, to ensure that the centrifugal advance has not been activated.

In the top picture below, the vertical "spark port" has a plastic cap on it. This is always found on the left carburetor, since it is not connected to the distributor vacuum advance.

The horizontal tube internal carburetor opening is below the throttle plate, so it has direct access to intake manifold vacuum. It is always connected to the choke vacuum break mechanism, which causes the closed choke butterfly plate to partially open as soon as a cold engine is started. (The vacuum break diaphragm mechanism has no impact on engine operation once the engine has warmed to normal operating temperatures and the automatic choke has disengaged).

I would like to encourage you to expand on your post and tell us more about yourself, as well as about your Corvair. Your personal assessment of your mechanical skills and abilities helps 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, your Corvair, and you plans for your Corvair will help us to write comments to you that are tailored to your needs and experience. Knowing where you live may also help, as your location may suggest some possibilities or solutions.

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 (.pdf) 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 club 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.

Common and Useful Corvair Websites

viewtopic.php?f=225&t=6007

[river_side]

Thanks for the great and useful response.
I will look to connect with a corsa club.
My corvair seems to run hot (the pressure/temp gage comes on after 15 min of driving) and it feels hotter than I think it should be.
I was hoping my timing was off, but it is at 16 degrees.
Any other reason as to the car running hot?
Runs quite well otherwise.
I have just finished rebuilding the carbs, and just did a head gasket on my 89 Corvette (my other Corvair!).
I am from the Inland Empire of California.

[terribleted]

First see if the temp/pressure light is being turned on by the temp sender or oil pressure sender. when the engine is running and the light is on unplug the oil temp sensor and see it the light goes off. If it does it is an oil pressure or pressure sender issue turning on the light. If the light goes off when you do this you had better measure the oil pressure with a gauge...if it is good replace the pressure sender. If the light stays on when the oil sender is disconnected then you may be overheating or the temp sender may be bad. Overheating is usually accompanied by detonation (pinging), but not always. You should certainly remove the oil cooler cover and make sure the top of the oil cooler is clean. Often the top of Corvair engines is covered with debris from rodents or other things around the fan which blocks airflow and cooling. Removal of the fan shroud and thoroughly cleaning the top of the engine is a good idea if this has not been done (you may be able to see debris on top of the heads by peering in through the sparkplug holes or through the oil cooler cover opening or maybe even peering in around the fan (a borescope type camera if available would make this easier).

[bbodie52]

1963 and later model Corvairs were manufactured with the oil pressure sending unit permanently located to the right of the generator/alternator. The diagram and drawing below focuses on the engine compartment wiring and layout for the warning switches. A ground at EITHER warning switch will cause the instrument panel PRES/TEMP warning light to illuminate. With the engine not running and the key ON, the warning light will illuminate as a bulb test. As soon as the engine is started, oil pressure will turn off the light as the switch opens.

1965-1969 Corvair Engine Compartment Wiring Diagram (CORRECTED)

The warning light in the Corsa or the Monza instrument panels work the same way. The oil pressure warning light bulb socket in the instrument panel is isolated from chassis ground. 12 VDC is connected to the bulb socket from the ignition switch via a power distribution harness with color code 20 B/P (20 Gauge Black with Pink Stripe). The center terminal of the bulb is wired via a 20 DBL (20 Gauge Dark Blue wire) all the way to both the cylinder head temp switch (right cylinder head) AND to the oil pressure warning switch (next to the alternator). A ground from either switch will complete the circuit and cause the warning bulb to illuminate. If your bulb fails to light with the ignition key ON, check for a loose or corroded connector in the engine compartment. The 12 pin multi-connector is sometimes the cause of a poor connection. Unplugging the wire from the sending unit next to the alternator and grounding it should cause the instrument panel warning light to illuminate when the key is ON.

NOTE THAT WIRE COLOR CODES CHANGED IN 1966. THE ATTACHED DIAGRAMS REFLECT 1965 COLOR CODES.

Left-click the image to enlarge it for better viewing or "Pan & Scan".Click a second time for maximum enlargement...

1965 Corvair Corsa Full Schematic (Rev. E)

Left-click the image to enlarge it for better viewing or "Pan & Scan".Click a second time for maximum enlargement...

1965 Corvair Monza Full Schematic (Rev. E)

CORVAIR COMBINED WIRING SCHEMATIC DIAGRAMS
viewtopic.php?f=225&t=12968&p=89250#p89250

Corvair engines seldom overheat as long as the fan belt is intact. However, if your engine has been sitting for a long time it may be suffering from a "critter invasion" with a lot of nest material packed under the sheet metal shroud. This blocks the air circulation around the cooling fins — possibly on only one side of the engine.