New Corsa clone owner in Arizona

[markdt]

Hello,

I'm in the Phoenix, AZ area and after wanting a Corvair since the early 80's in High School, I finally took the plunge and purchased one. It is a bit of a Frankencar in that it is a Corsa clone assembled from the amalgamation of a 65 Monza convertible (good body) with a 66 Corsa (good drivetrain). The gentleman I purchased it from was doing a total restoration when health reasons required the sale. The engine was rebuilt in California and the transmission and differential rebuilt by a local Corvair guru who sold the car to me on behalf of the owner. In addition, new wiring, brake system, suspension, tires, and gas tank were added. The power top still works but has a minor tear near one corner. It is a California/Arizona car so the rust issues are a small hole on the passenger door sill-- the rocker bottom is solid, and a pretty bad bottom corner of a rear fender from I'm guessing a reversing accident. I plan on doing the body work and, though the paint appears original, re-painting due to very bad fading, crazing, cracking and minor surface rust at various points around areas of high wear like edges of panels and door hinges. The original front antenna was replaced with a power unit in the rear and the plug used to fill the front hole needs to be ground down or removed and redone with a circular patch.

I'm a fair shade tree mechanic with a tool addiction, and have some experience with minor body work (cutting out rust, welding in easy patches, and bondo repair of defects after pulling/hammering out dents... never done any fabrication of metal work). I've never worked on an air-cooled, carbureted engine other than an old motorcycle.

When I bought it, the car would turn over but not start. We were baffled because the car had been driven for 20 miles after the rebuild. It was thought the car had been converted to electronic ignition and perhaps that was where the fault lay. I trailered it home (an ordeal due to my ignorance of loading a non-running Corvair onto a trailer without a winch) and after tinkering with the distributor, coil and condenser still couldn't get spark to the plugs though there was fuel squirting into carbs and spark at the points. Turns out the car had not been converted to electronic. After hours of exasperation and searching through this forum, I could not figure out why the car was not getting spark at the plugs. I used a multimeter on the coil and condenser and they seemed fine, but I went ahead and replaced with new just in case. My neighbor (a much more experienced mechanic in general but no Corvair experience either) couldn't figure it out either. Finally, I found a reference to removing all wires from the coil except the power wire and ground. I removed the condenser wire on the coil positive and the brown tach wire from the negative. The car fired right up. But, if I touch the brown wire to the negative post while running, the car immediately stalls.

I have gotten through all the posts in the "mechanical questions" section but have read enough to semi-understand about the built in resistance wire and the switching from 12 volts at the coil to 7ish volts after starting. I haven't been able yet to find anything regarding a similar situation where the car won't start or keep running if the brown tach wire is attached. So, I've got a working clock, vacuum gauge, fuel gauge and temperature gauge, but no speedometer or tach. The speedo is a separate issue I'm assuming unless it is somehow related to the brown wire as well.

Anyone run into this issue before? I'm absolutely willing to ditch the points and switch to an electronic ignition if that will kill two birds with one stone.

The other question was about the shift linkage. How loose is it normally? I'm used to pretty notch like linkages from prior standard transmissions and it seems like I have to hunt for the right placement to get the car into 1st or the 2 to 3rd gear shift. Is this just the way 60's non-gated shifters were or should I get under and check whether the linkage is worn at the shifter or transmission?

Attached are some photos of the car including the ignition coil with brown wire removed.

Thanks for any help that can be provided.

[joelsplace]

Here's all the Kent Moore special tools for Corvairs or at least most of them:
https://murfy.us/doku.php?id=corvairear ... orted_by_j
Blue Chip Machine makes some really nice Corvair specific tools. The harmonic balancer tool is great and he also makes special long nuts for the belt adjustment.

[bbodie52]

Welcome to the Corvair Forum!

Assuming your Corsa clone (Monza chassis) was the recipient of a transplanted Corsa instrument panel, there is a chance that the rewiring necessary to connect all of the instruments in the Corsa panel to the Monza wiring harness may have been done incorrectly. In the schematic wiring diagram below, I have combined three pages of diagrams into a single diagram that you can enlarge (by clicking on it two times) for a detailed, close-up view that you can trace from the coil to the tachometer. A multimeter may be helpful with troubleshooting and fault isolation, as it sounds like the brown tachometer sensor wire is shorting to GROUND somewhere, so connecting it to the coil is killing your engine with a continuous ground connection.

The speedometer and manifold pressure/vacuum gauges are the only two instruments in the panel that do not use electricity to function. The vacuum gauge (which serves little purpose in a non-turbocharged Corsa), simply uses a thin nylon plastic tube to connect the gauge to the vacuum balance tube that connects the right and left engine intake manifolds. The speedometer functions by the mechanical speedometer cable that connects the left front wheel grease cap to the speedometer input, which spins a magnet inside the speedometer to cause a gauge needle rotation which provides a calibrated speed reading. No battery voltage is needed for it to function. (See the attached document: Corsa Speedometer Overhaul - CORSA Communique May 2012 for a detailed explanation of the speedometer function).

If you follow the brown tachometer wire, you should find that it makes its first stop in the 12-pin multi-connector on the left-front portion of the engine compartment.



It should pass through that connector, but there is a possibility of an electrical short inside the connector. You might want to carefully separate the two halves of the shell housing and inspect the metal connector pins for a bent or damaged/shorted pin. If the brown wire is sound and electrically passing through properly, the next stop is behind the instrument panel, at a two-wire connector that was improperly shown in the 1965 Corvair Chassis Shop Manual. In the shop manual diagram, the brown wire enters in the horizontal portion of the connector, but for some reason the technical writer made a mistake and had it exiting on the top vertical portion (as a brown with white stripe wire). Since this was physically impossible, I made a desktop correction and swapped the two wires in my revision of the diagram. This change connects the brown coil wire to the tachometer sensor connection, instead of the cylinder head temperature gauge via the 20 B/LG wire. When the transplant of the Corsa instrument panel was made into the Monza, there might be a possibility that the necessary wiring modifications were incorrectly made. Finally, the Corsa tachometer in your instrument panel could have an internal fault and may be defective, which could be the reason it is killing your engine when connected. You will have to determine the actual cause with some testing and inspection. You could start by using the multimeter to see if you find a chassis ground when you set the meter to measure resistance (ohms). Touch one test lead to the brown wire connector, and the other test lead to chassis ground. If you discover a short to ground, you could try disconnecting the brown wire from the tachometer to see if this removes the short to ground. If it does, you have a bad tachometer. If it does not, you probably have a wiring harness problem.

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

1965 Corvair Monza Full Schematic

CORVAIR COMBINED WIRING SCHEMATIC DIAGRAMS
viewtopic.php?f=225&t=12968

[plrgpr]

Looks like a great car. BTW, I have one just like it and it’s a clone also!

[markdt]

Thank you for the responses and help. Yes, it has a Corsa instrument cluster. I forgot to include that photo.

That wiring information is extremely detailed and helpful. I'll be out there with my multimeter checking continuity tonight. I'll see if I can track down the issue. I thought it might be a grounding issue but was reluctant to blindly start tracking down the problem.

Given the information about the vacuum gauge, maybe I'll look into turning that space into a true oil pressure gauge to supplement the warning light.

Looking forward to joining the community of car lovers.

[markdt]

Gary,

That is a beauty. Love the look of the wire knock-offs. And jealous of the neatness of the garage organization.

[66vairguy]

The "brown" wire goes to the tachometer input which is a high impedance input (very little electrical load). It should have no effect on coil operation.

Most likely the wire is shorted to ground or the tachometer input is shorted to ground.

Disconnect the brown "input" wire from the tachometer to determine if it is the wire, or tachometer shorted to ground. If the tachometer is bad then find a good used one. DON'T throw a bad tachometer away. Rumor has it a vendor is going to rebuild used ones with modern parts.

It's getting difficult to find a repair person. A couple reputable folks quit repairing them. The biggest problem are the meters. They are wearing out and are not repairable. I had one I spent hours on and it worked great for a month - then the meter return spring broke and it was junk. If I had done it for a customer they would not have been happy. So I decided not to pursue repairing them.

I've fixed about six for myself and club buddies (no charge) - but it is usually a very labor intensive effort. Fixing the electronics is not a bad job. Calibrating the tachometer is a combination of electronic and mechanical adjustments to get them accurate. My average to calibrate is SIX HOURS!

[markdt]

The disconnected brown coil wire had continuity to ground and no resistance. I got up under the dash (not so easy anymore in my mid-50's) and disconnected the instrument wiring harness. I couldn't contort enough to only remove the brown wire from the connection on the back of the tach, though I could see it. I then started the car and when I reattached the brown wire to the coil it no longer caused a stall. Based on the above, that means the short is related to the tach itself correct? When you say the tachometer is shorted to ground is there a potential cure for that (like checking other connections in the harness or other wires leading to tach) or does it mean rebuild or replace?

I'm searching the forums for a guide to getting the tach itself out. Looks like I would have to disconnect a lot of stuff to get the dash off. If I do that, it sounds like rebuilding the tach may be out of my league or be reliability futile.

[plrgpr]

Thanks Mark. The knock offs are the optional Corvair hubcaps. I believe that Clark’s offer them used. I’m sure the “spinners” are available new as repros from Clarks. Sounds as if there is a short to ground on the brown wire. A quick check would be to run a new wire from the coil directly to the tach, outside of the engine compartment through the window to the dash. See if the car runs and tach works with the new wire....

[markdt]

It never occurred to me to run an independent wire. I'll try that.

[plrgpr]

.....worth a try. If the engine quits with that wire, then you know it’s in the tach.

[markdt]

Kudo's to Gary!! I disconnected the instrument harness again and ran an independent wire from negative of coil to where the brown wire connects to the tach (marked with a negative in marker on the back). Pink wire is on the positive and a grey wire going to the bulb. Sure enough, when I touched the new wire to the brown wire connection on the tach it caused a stall situation. I didn't see anything else up there that could be causing a ground fault so it must be internal, correct? At least I know now that it isn't a problem in the ignition system, though I may go ahead and switch to a Stinger or Pertronix system anyway.

Thanks for all the help. I see that Clark's is sold out of tachometers so I'll start searching for a replacement.

Next, on to diagnosing the speedometer issue.

[plrgpr]

[bbodie52]

...I've got a working clock, vacuum gauge, fuel gauge and temperature gauge, but no speedometer or tach...

Disconnecting the small 2-wire connector behind the instrument panel would disconnect the brown tachometer sensor wire from the coil negative connector (ignition points side) and would also disconnect the left cylinder head thermistor from the cylinder head temperature gauge (20 B/LG wire).

It is surprising that the electro-mechanical clock is still functioning. My understanding is that the internal electrical contacts that cause the clock to rewind periodically usually burn out, causing the clock to die. There was a kit sold on eBay that replaces the internal mechanism with an electronic quartz analog clock mechanism, while retaining the original Corsa clock face and hands. I also noted a listing for a rebuilt/repaired original Corsa electro-mechanical clock, but the seller wants $125 for the replacement ($10 refund for a non-working core).
https://www.ebay.com/itm/Chevrolet-Corv ... SwOfFecOJH

Clark's Corvair Parts now sells the Corsa quartz clock unit and some speedometer repair items...
http://www.corvair.com/user-cgi/catalog ... w_page=210
Part number C11531: CORSA CLOCK WITH QUARTZ MOVEMENT

NOTICE: Price includes core value: $60.00. You will be issued a refund of $60.00 when you return the used part.

Weight: 1 lbs 0 oz
Catalog Page(s): 210
Price: $ 202.45

Assuming you have some Corsa speedometer problems...

The odometer drive often wears out in these aging mechanical speedometers, and serviceable original replacements are somewhat rare. If you have ruled out the speedometer cable as the source of your trouble, you may find that Corsa speedometer repair is somewhat difficult — as some internal components seem to be made of unobtainium. I have attached a copy of a CORSA magazine article on this subject for your information...

Corsa Speedometer Overhaul - CORSA Communique May 2012.PDF

http://www.corvair.com/user-cgi/catalog ... w_page=210
http://www.corvair.com/user-cgi/catalog ... w_page=132
Part number C9701: REBUILT 65-66 CORSA SPEEDO

NOTICE: Price includes core value: $60.00. You will be issued a refund of $60.00 when you return the used part.

Weight: 1 lbs 0 oz
Catalog Page(s): 210,U-47
Price: $ 299.60



Aftermarket electronic speedometers may be adapted to the Corsa instrument panel. Corsa gauge mounting plates are available from Seth Emerson's Performance Corvairs...
https://www.perfvair.com/dash-parts-steering-columns/



Contact Us:
Performance Corvairs
Seth Emerson
3462 Kirkwood Dr.
San Jose, CA 95117

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


https://www.google.com/search?q=electro ... e&ie=UTF-8

https://www.vdo-instruments.com/instrum ... meter.html


https://www.summitracing.com/search/par ... ner=SREPD4


https://www.autometer.com/
https://www.jegs.com/c/Gauges-Tachs/10331/10002/-1


The Corsa and Monza instrument panels can develop problems with the electric instruments and/or illumination lights. The panels are plastic, so a metal conductive grounding strap links the electric gauges together and then ties them to chassis ground at a single point. If the single screw that attaches that grounding strap to the metal dashboard becomes loose or corroded, the electrical ground to the instrument panel components may be lost and this can disrupt the operation of the electric gauges and illumination lights.

That Corsa-only gauge is really there for turbocharged Corsas, but it is only needed in non-turbo Corsas to fill the hole in the instrument panel. It provides very little valuable information in non-turbocharged engines. It only tells you when the throttle is closed (high vacuum), or open (close to zero manifold vacuum). On my 1965 Corsa I chose to remove the chronically failed clock and relocated the fuel gauge to the top (in place of the clock). I then installed two VDO aftermarket gauges in the two bottom holes, providing me with an ammeter or voltmeter to monitor the electrical system, and an oil pressure gauge.

Other ideas...

[66vairguy]

Kudo's to Gary!! I disconnected the instrument harness again and ran an independent wire from negative of coil to where the brown wire connects to the tach (marked with a negative in marker on the back). Pink wire is on the positive and a grey wire going to the bulb. Sure enough, when I touched the new wire to the brown wire connection on the tach it caused a stall situation. I didn't see anything else up there that could be causing a ground fault so it must be internal, correct? At least I know now that it isn't a problem in the ignition system, though I may go ahead and switch to a Stinger or Pertronix system anyway.

Thanks for all the help. I see that Clark's is sold out of tachometers so I'll start searching for a replacement.

Next, on to diagnosing the speedometer issue.

A few months back I was at Jeff's Calif. Corvair and he mentioned he had a few good used tachometers. Give him a call. But first ---- if you pull the instrument cluster (no fun and you have to remove the headlight and wiper bezels, drop the steering column an inch or so by removing the bracket and I pull the steering wheel - just me) check to see if the tachometer terminal insulating bushing is cracked or missing. Since the car was running fine with the Corsa instrument cluster (as I understand your comments), then had an issue it is probably a failed capacitor on the circuit board, but never assume until you take a look.

[azdave]

Several local guys were watching that sale. Looked decent in the pics. I'm near US60 and Stapley in the east valley but not being too social these days trying to stay healthy. Sometimes the worst part of purchasing a used car is trying to figure out all the mods previous owners did to it. Wiring changes are the worst. I see they also changed it to an internally regulated alternator.