'63 Monza dies at idle in drive

[happystang]

Hi everyone,

My '63 Monza convertible keeps dying at idle when in drive. Both carburetors were rebuilt by a reputable shop that specializes in Corvairs, however the problem still persists. I bought one of those air flow meters to balance the carbs, but it seems that one of the carbs keeps losing its tune/balance. I found a rather nasty vacuum leak coming from the throttle shaft on the driver's side carburetor- there seems to be a lot of play on the shaft that changes the idle when wiggled. I sprayed some carb cleaner at the throttle shaft and actually managed to shut the engine off when running in neutral, indicating that air is being sucked in from the outside through that shaft.

There is a large drop in RPM when put in drive from neutral with harsh engagement. The neutral RPM has to be set fairly high for it to idle remotely well in drive.

I went ahead and replaced all vacuum hoses, the cap/rotor and plug wires. Ignition is a pertronix 2 with matching coil.

I'm assuming it's time for replacement carbs? I was looking at this pair of rebuilt carbs on ebay, does anyone have any other recommendations?

https://www.ebay.com/i/323946145232?chn ... cpEALw_wcB

[bbodie52]

...I went ahead and replaced all vacuum hoses, the cap/rotor and plug wires. Ignition is a pertronix 2 with matching coil...

The Pertronix Ignitor II has been known to have some sensor problems managing a slow idle, such as found with a Corvair running a Powerglide automatic transmission in DRIVE. I believe the problem appears when the idle drops too low for the Pertronix Ignitor II electronic module to manage the pulses properly. The ignition system may begin to skip every other pulse, causing an ignition system misfire. This may show up with the engine dying when you shift a properly idling engine from NEUTRAL to DRIVE. The load of the torque converter may slow the engine to the point that the Pertronix unit begins to malfunction. The problem is not present in the Pertronix Ignitor I, the Crane Cams XR700, or the Stinger electronic distributor marketed by Performance Corvairs (Seth Emerson).

More Info...

ELECTRONIC DISTRIBUTOR UPGRADE/REPLACEMENT OPTIONS
viewtopic.php?f=225&t=15101

For those considering modern ignition system options for their Corvair...

The Pertronix Ignitor II has been known to have some sensor problems managing a slow idle, such as found with a Corvair running a Powerglide automatic transmission in DRIVE. I believe the problem appears when the idle drops too low for the Pertronix Ignitor II electronic module to manage the pulses properly. The ignition system may begin to skip every other pulse, causing an ignition system misfire. This may show up with the engine dying when you shift a properly idling engine from NEUTRAL to DRIVE. The load of the torque converter may slow the engine to the point that the Pertronix unit begins to malfunction. The problem is not present in the Pertronix Ignitor I, the Crane Cams XR700, or the Stinger electronic distributor marketed by Performance Corvairs (Seth Emerson).

It was the Ignitor I version that could be damaged by leaving the key in the ON position without the engine running. The Crane Cams XR700 displays none of these problems. Both Pertronix modules prefer a full 12 VDC power source — bypassing the factory integrated resistor wire.

The primary reason for the factory integrated ballast resistor / resistor wire that is present in early vintage ignition systems was to reduce the voltage powering the ignition coil, which also in-turn reduced burning and arcing of the ignition points that occurs each time the points open or close. This system increases the coil voltage to full battery voltage during initial engine starting (when the starter is cranking the engine) to temporarily boost the ignition coil spark plug voltage output to promote engine starting. Once the engine starts and the starter system disengages, the ignition coil voltage reverts to a source routed through a ballast resistor that reduces coil input voltage from a nominal 12 VDC to approximately 7 VDC. This produces a lower spark plug voltage that is deemed sufficient for normal engine operation. The reduced coil input voltage prolongs the life of the ignition points electrical contacts, and has a secondary benefit of causing the ignition coil to run at cooler operating temperatures.

Many high performance ignition coils were designed to function powered at full battery voltage (12 VDC) all the time, to permit full-time maximum spark plug voltage. Also, most aftermarket electronic breakerless ignition systems that eliminate the use of ignition points (Pertronix Ignitor I and Ignitor II, Stinger electronic distributor, etc.) require a full 12 VDC power source to power the electronic circuitry. However, the Crane Cams XR700 electronic module was designed to be powered through the vehicle manufacturer's ballast resistor / resistor wire (nominal 7 VDC). Connecting it to a full 12 VDC could cause it to overheat and possibly malfunction. The requirements of any newly installed aftermarket performance ignition coil or electronic breakerless ignition system must be considered when installing the new system. Installation instructions must be carefully reviewed to ensure proper installation.

http://www.corvair.com/user-cgi/catalog ... IN&page=74


Ted in Atlanta has a lot of professional Corvair experience. I remember his recommendation...

...I love my Crane ignitions. I have only ever seen one that had failed. Something I can not say about the Pertronix units where failure is somewhat common from what I have seen.

Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up. Full time restoration tech and mechanic. https://www.facebook.com/tedsautorestoration

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




NOTE: THE CRANE CAMS SYSTEM IS NOW MARKETED AS A FAST XR700, DROPPING THE CRANE CAMS NAME

FAST 700-0226 XR-700 Points-to-Electronic Ignition Conversion Kit for Domestic 4, 6 and 8 Cylinder Engines and VW/Bosch 009 Distributors
https://www.amazon.com/FAST-700-0226-El ... pons&psc=1

https://www.summitracing.com/parts/fst- ... gI0K_D_BwE
https://www.jegs.com/i/FAST/244/700-0226/10002/-1

https://www.fuelairspark.com/ignition-s ... ition.html


It is not a bad idea to relocate the coil mount position. The standard installation of the ignition coil was always mounting it directly on the right cylinder head. The cylinder head on an air cooled engine gets very hot, and a significant portion of that heat can be transferred via the coil mounting bracket to the coil body itself. I would recommend relocating any coil as shown in the pictures below.

[terribleted]

Try replacing the throttle shaft in the carb that is loose (or both). The shafts wear faster than the carb bases and if there is vacuum leak here often a new shaft will fix it.

[bbodie52]

See Throttle Shaft Seal Kit and Teflon Shaft Bushing Kit...


http://www.corvair.com/user-cgi/catalog ... ow_page=59

Part number C1473: THROTTLE SHAFT SEAL KIT FOR 2 CARBS (KIT FOR 4 CARBS=C1474)

Weight: 0 lbs 4 oz
Catalog Page(s): 59
Price: $ 10.40


Part number C5271: TEFLON BUSHING KIT FOR 2 CARBS

Weight: 0 lbs 4 oz
Catalog Page(s): 59
Price: $ 26.85

[terribleted]

I prefer not to use the shaft seals as they cause drag on the carbs meaning more throttle effort (and spring tension to close). If I can not get a suitable result with a new shaft I find a better base.

[happystang]

WOW. It looks like the Pertronix might be the issue!! I have those exact symptoms. Does anyone have a part number for the Pertronix 1 that will fit a '63 Corvair? 1162A seems to be the correct unit based on my research.

[terribleted]

Use points or a FAST XR-700 IMO

[bbodie52]

Pertronix I is listed in my previous post, but it is called "Magnetic Ignitor" on the Clark's page...

http://www.corvair.com/user-cgi/catalog ... IN&page=74

Flamethrower II Coils WILL NOT work with C2851 or C6790 This is because of the ultra-low Pertronix Flamethrower II coil impedence of 0.5 ohms. If you bought a Flamethrower II coil, you would need to install a Stinger Electronic Distributor to have an electronic module that can handle the high current, low resistance of the Flamethrower II coil (or switch to a standard coil with 1.5 ohms or higher primary resistance).

You might want to call Seth Emerson (also president of your local CORSA club chapter) to discuss your options further and get his recommendations.

Contact Us:
Performance Corvairs
https://www.perfvair.com/

Seth Emerson
3462 Kirkwood Dr.
San Jose, CA 95117

Email: Sethracer@aol.com
Phone: (408) 247-2237


More Info...

ELECTRONIC DISTRIBUTOR UPGRADE/REPLACEMENT OPTIONS
viewtopic.php?f=225&t=15101

[happystang]

Update:

The swap to Pertronix 1 fixed the idling issues! Thank you all for the help