Have you checked the supply voltage with a voltmeter, both when starting out and when it starts acting up? It should be about 12 VDC when cranking and about 7 VDC in normal operation. There is a resistor wire in the wiring harness, near the 8-pin multi-connector. The schematic diagram below shows how the primary ignition wiring is set up.
When you are cranking the engine, a full 12 VDC comes from the starter solenoid and feeds the coil, to provide a hotter spark to enhance starting. The moment you release the key and stop cranking the engine, the solenoid disengages and this shuts off the 12 volts from the solenoid, leaving only the reduced voltage fed through the resistor wire. This lower voltage is normally adequate for a running engine, and is reduced from 12 volts to approximately 7 volts by the special resistor wire that is embedded in the factory wiring harness.
If you measure the voltage between the coil positive terminal and ground with the key on/engine running, it should be around 7 volts. If the car begins acting up after driving it for a while, recheck the voltage. If the voltage has gone down, check the voltage at the battery. With the engine running the charging voltage seen a the battery should be about 14 volts. If the battery voltage appears to be good but the voltage at the coil positive terminal has decreased, it is possible that the resistor wire is failing. When resistors get hot the resistance tends to increase. If the resistor wire is failing it is conceivable that the increasing resistance produced by a hot resistor wire is reducing voltage that gets to the coil. This would decrease the spark produced by the coil as the voltage fed to the coil decays.
You could try an experiment by fabricating a jumper wire to temporarily feed 12 volts to the coil positive terminal directly from the battery positive lead. With a full 12 volts feeding the coil, does the engine performance come back? If it does, a faulty resistor wire would likely be the cause. The ignition points will not last very long with a full 12 volts passing through them. Over time they would arc and burn, and would have to be replaced more frequently. That is why GM put the resistor wire in the circuit in the first place. If the resistor wire is proven to be failing, it can be bypassed and an automotive ballast resistor can be purchased at a parts store to replace the resistor wire. Alternately, you might consider replacing the points with a breakerless system from Pertronix, or even replacing the old distributor with a new distributor from Performance Corvairs.
http://www.perfvair.com/electronic-distributors/ The distributor from Performance Corvairs contains the breakerless electronics, which runs at a full 12 volts and does not need a resistor wire or ballast resistor. The new distributor eliminates the 52 year old distributor completely, and the results is better performance, no more points and condenser, and solid performance from the new ignition system.
Anyway, check the supply voltage fed to the coil, and determine if the possibility of a failing resistor wire seems to be the source of your trouble. If it is, you will have to decide on how you want to correct the fault.
As for your overheating generator, have you polarized the generator? have you had the generator tested or considered upgrading to an alternator?
I don't know if the information below would apply to your charging system problem. If you ever had your electrical system disconnected, it should have been polarized when reconnected to ensure the proper configuration of your charging system. The manual mentions the possibility of arcing and burning contacts if this is not done, but I don't know if that arcing would be visible in the generator, or would only occur in the voltage regulator.
Whenever the battery is disconnected from the vehicle for any reason the polarization procedure should be performed.
1960-1964 Corvairs used generators in their charging systems. These generators were replaced with charging systems using alternators in 1965-1969 Corvairs. Generators often needed to be
polarized when the battery was disconnected or the generator was disconnected and removed or reinstalled to get it properly functioning again.
The shop manual states that if the system is not properly polarized a reversed polarity can cause arcing and burning of the contact points. This is something that is unique to generator-based charging systems, and is not applicable to alternators.
As shown in this illustration from page 8-6 of the 1961 Corvair shop manual, the center voltage regulator
GENERATOR terminal is directly wired to the Armature terminal on the generator. The
Field terminal on the regulator is wired to the generator
FIELD terminal. The charging voltage output from the generator emanates from the generator Armature via the heavier 14Gauge wire.
When polarizing the generator, the temporary connection must be made between the BATTERY terminal on the Voltage Regulator to the GENERATOR (Armature) terminal.
If the generator has failed, you might want to consider a conversion to an alternator at this time, rather than spend money on a rebuilt generator and possibly on a new voltage regulator. Such a modification is a common upgrade in EM Corvairs. It requires changing the oil filter/generator adapter to provide a proper mount, and removing the old charging system and replacing it with a new alternator. Many suitable alternators have an internal integrated electronic voltage regulator, which can simplify the upgrade by eliminating the old external voltage regulator configuration. If you would consider such a modification, now would be the time.
A conversion from a generator to an alternator in 1960-1964 Corvairs is often a topic of conversation and sometimes confusion. I have located some good material on this subject, and have compiled it here. Hopefully this information will be of some help.
There are several options in the conversion:
- Use an externally regulated 10DN Delco alternator, as seen on late model 1965-69 Corvairs.
- Use an internally regulated 10SI or 12SI Delco alternator off a slightly later GM product.
- A true one wire setup. Here a special self exciting regulator is installed in a 10SI style alternator. Control of the dash idiot light is lost if this is used.
The explanation shown below, along with its website link, seems to be one of the best explanations I've seen seen that describes some of the Delco alternator options available that could be fitted to a Corvair. (Keep in-mind the reverse rotation of the Corvair engine, which does not affect the alternator charging system but must be considered when fitting a cooling fan and pulley to the alternator — since the cooling fans are designed to rotate either clockwise or counter-clockwise. Proper air circulation is important for cooling an alternator).
A standard Corvair alternator output capacity:
- Alternator P/N: 1100639 — 35 Amps
- Alternator P/N: 1100698 — 45 Amps
Greater charging capacities might be considered if the Corvair is fitted with special high-current, high intensity headlamps, some form of electric heater, or a custom sound system with external amplifiers supporting a special speaker configuration with subwoofer(s).
An alternator with an internal electronic voltage regulator makes good use of the increased reliability of a solid-state voltage regulator to replace the 1960s vintage external electro-mechanical voltage regulator. However, a switch to a single-wire alternator instead of a 3-wire alternator cannot be justified, and is not desirable in my opinion. The reasons are clearly described below...
Alternator Conversion
Selecting a Delco SI-Series Alternator
[url]http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html[/url]
To replace an EM generator with an alternator, the oil filter and generator mount adaptor must be replaced with the oil filter and alternator mount adaptor found on 1965-1969 Corvair engines. These used adaptors can usually be obtained from sources on eBay or from sources like the Corvair Ranch in Gettysburg, Pennsylvania...
http://www.corvairranch.com/
Suitable alternators can be sourced from normal Corvair suppliers, auto parts suppliers, eBay, local automotive junk yards, etc.
This link provides some additional information on the CCW rotation alternator fan and proper cooling for a high-capacity alternator mounted on a Corvair engine...
http://corvaircenter.com/phorum/read.ph ... 130,612166
More information on fitting newer-design Delco alternators to Corvairs...
http://www.unm.edu/~geoffj/Vair/Alternator.html
http://www.corvair.com/user-cgi/catalog ... N&page=84A
1966 Corvair Corsa Convertible
The possibility of a failing coil or condenser due to heat buildup is certainly feasible. If the source voltage proves to be within normal parameters, another failing component that might be degraded by heat is certainly possible. Further troubleshooting and fault isolation should help you to find the cause.
Search CorvairForum
Calendar
Birthdays
Newest members
Corvair Vendors