Powerglide

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Munypit
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Powerglide

Unread post by Munypit » Sat Sep 02, 2017 6:25 pm

When put in reverse or drive the engine dies. Have set idle up and set it down, still does same.
1962 900 corvair. Anyone have any ideas?

Jerry Whitt
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Re: Powerglide

Unread post by Jerry Whitt » Sat Sep 02, 2017 7:30 pm

Start with the basics. What is the dwell ? What is the initial timing? What is idle speed in neutral? What are you trying to set idle speed when in drive?

Let us know the basics, we can advise further.
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64powerglide
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Re: Powerglide

Unread post by 64powerglide » Sat Sep 02, 2017 8:58 pm

Don't forget to check the vacuum line that goes to the modulator valve, if the vacuum is to low pressure will build up in the pump & the bands will grab quicker instead of being kinda smooth. Make sure the modulator valve is good too.
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cnicol
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Re: Powerglide

Unread post by cnicol » Sat Sep 02, 2017 10:47 pm

It's counter-intuitive, but the slower the idle, the less impact there will be when shifting into drive. It's mostly because the torque converter can't connect at low rpm. Another factor is a high rpm idle involves some mechanical advance from the distributor. When the idle rpm decreases (because it's high enough for the TC to have impact, you also lose the mechanical advance which doubles the impact. A good neutral idle rpm target for a PG car is around 500-550 rpm.
'61 140 PG Rampside
'66 Rear Alum V8 4-dr
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Re: Powerglide

Unread post by bbodie52 » Sat Sep 02, 2017 11:18 pm

:welcome2: Welcome to the Corvair Forum!

Is the ignition system a stock, original factory configuration, or are any modifications/upgrades involved?
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Re: Powerglide

Unread post by 64powerglide » Sun Sep 03, 2017 8:33 am

cnicol wrote:
Sat Sep 02, 2017 10:47 pm
A good neutral idle rpm target for a PG car is around 500-550 rpm.
500-550 RPM when the trans is in gear not in neutral and that's hard to do when you cannot get it to idle in gear. Just keep playing with the carb settings until it stays running. I had my 64 powerglide checked out by a transmission guy last year & he adjusted the low band & that did wonders. He is retired but still owns the property that his shop was in but it's run by another owner & he comes in when they get a job like a Corvair because he's been doing them since the 60's & he know his stuff. I'm in that RPM range in gear but it jumps up to around 1,500 in neutral.
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Munypit
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Re: Powerglide

Unread post by Munypit » Sun Sep 03, 2017 10:03 am

It does have a pertronix ignitor module in distributor. Will get around to other checks as time permits.

Thanks for info

Munypit

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Re: Powerglide

Unread post by 64powerglide » Sun Sep 03, 2017 10:33 am

Here is a good read on the Corvair powerglide trans, it is long but when you have some time you should read it.

http://www.corvair.org/chapters/corvana ... ld_man.pdf
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bbodie52
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Re: Powerglide

Unread post by bbodie52 » Sun Sep 03, 2017 2:16 pm

bbodie52 wrote:Sun Sep 03, 2017 1:18 am

...Is the ignition system a stock, original factory configuration, or are any modifications/upgrades involved?
When I read your earlier comments describing the difficulties you are having with your Powerglide-equipped Corvair, the very first thing I thought of was a known problem when coupling a Powerglide Corvair with a Pertronix Ignitor II aftermarket ignition system. That is why I asked if your ignition system was stock or modified. Your response only partially answers the question, because there is a difference in the Pertronix ignitor and ignitor II systems.
Munypit wrote:Sun Sep 03, 2017 12:03 pm

It does have a pertronix ignitor module in distributor. Will get around to other checks as time permits
If the Pertronix module in your distributor is the ignitor II version, you may have a compatibility problem because of your Powerglide transmission…

Image
bbodie52 wrote:I have not had personal experience with the reported problem of combining the Pertronix Ignitor II with an automatic transmission based Corvair engine. But the reports that I have read seems to indicate that the Pertronix Ignitor II has a difficult time with interpreting the magnetic pulses from the distributor at an ultra-slow idle speed. Apparently the system electronics cannot properly trigger the ignition coil discharges when the engine slows beyond a certain threshold. With the Powerglide automatic transmission in DRIVE, the load imposed on the engine by the torque converter slows the idle speed just enough to disrupt the function of the Pertronix Ignitor II. I have not heard this problem reported with the older model Pertronix Ignitor I.

It might be worthwhile for you to contact Pertronix Technical Support at :link: http://www.pertronix.com/support/. Click on Support Ticketing System and open a new ticket. Leave a description of the issue you are experiencing and the reported information you have received regarding the Pertronix Ignitor II with a Corvair engine coupled with the slow idle speed presented by an automatic transmission load. Perhaps you can discuss this with one of their technicians and they may be able to suggest a solution. I would guess that installing a Pertronix Ignitor I may resolve your problem, and perhaps they will offer an exchange. Otherwise you may have to try selling your old electronic ignition and replacing it with either a Pertronix Ignitor I or a Crane Cams electronic ignition system. You might also consider replacing your existing distributor with a new Stinger distributor that is offered by Performance Corvairs
:link: https://www.perfvair.com/stinger-ignition-distributors/.

The Stinger distributor design also includes an electronic ignition system with a magnetic pulse trigger. If you do consider this upgrade you might wish to contact Seth Emerson at Performance Corvairs to discuss your intended application and to confirm with them that they have had no problems with their distributor when coupled to a Powerglide-equipped Corvair engine.

I do feel that an ignition system upgrade that includes abandoning the use of ignition points and switching to an electronic ignition is a worthwhile effort. The prices listed below are for an Pertronix Ignitor I or a Crane Cams system from Clark's Corvair Parts. This would include modifying your old distributor and retaining it on your engine. The last option is also the most expensive, but it replaces your aging distributor with a brand-new unit.

Part number C6790: MAGNETIC IGNITOR-ELECTRONIC IGNITION FITS ONLY 62-69 DISTRIBUTORS AND REQUIRES 1.5

Weight: 0 lbs 12 oz
Catalog Pages(s): 74
Price: $ 90.25


Part number C2851: CRANE CAMS ELECTRONIC IGNITION-62-69 ONLY*MUST HAVE CORVAIR ENGINE HARNESS OR COIL WITH RESISTOR

Weight: 2 lbs 0 oz
Catalog Pages(s): 74,OT,21
Price: $ 123.95


Stinger Electronic Distributor https://www.perfvair.com/stinger-ignition-distributors/

The Distributor sells for $200


If your ignition coil is a Flame Thrower II unit, it has and ultra-low 0.6 Ohm primary resistance. That particular coil will only operate with a Pertronix Ignitor II control module. It will probably also work with the Stinger distributor, but you should confirm that. If it is a conventional Pertronix Flame Thrower coil, they are available with a 1.5 or 3.0 Ohm primary resistance. If the ballast resistor wire is still present in your Corvair wiring harness, the 1.5 ohm version would be correct. If the resistor wire has been bypassed to deliver a full 12 V DC to the coil, the 3 ohm coil would be appropriate.

Obviously modifying your ignition system to incorporate a more modern electronic ignition requires a little homework. Each available system that upgrades your Corvair ignition has specific operating parameters that must be considered when fitting it to your older vehicle. The correct source voltage for the electronic module is an important consideration. Matching the electronic module with a correct ignition coil is also important. The ultrahigh voltage, high performance ignition coils are generally overkill for the Corvair engine. The compression ratio in the Corvair engine and the relatively low maximum RPM speeds do not place significant demands that would require a high secondary voltage to fire the spark plugs. The main advantage of electronic ignition is low maintenance and high reliability, that is achieved by eliminating the ignition points and condenser. Whatever your choice, it may be partially determined by the response you get from Pertronix technical support. The type of ignition coil that was installed on your Corvair may also limit your choices. Once you have gathered information from Pertronix you can make a decision on which type of system you will find is best for your Corvair and your budget. If you have any questions, please post them here.
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Brad Bodie
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Re: Powerglide

Unread post by Munypit » Sun Sep 03, 2017 2:56 pm

This is unit that was in car when I bought it... I've attempted to check
Timing, but if I remove vacuum line and plug it the car will barely start and will not stay running
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cnicol
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Re: Powerglide

Unread post by cnicol » Sun Sep 03, 2017 7:41 pm

"This is unit that was in car when I bought it... I've attempted to check Timing, but if I remove vacuum line and plug it the car will barely start and will not stay running"

Craig replies: The black, Pertronix-1 in your picture should be fine with the low rpm idle of a powerglide. The other part of your comment is the root of the problem: Your carburetors and timing are way off. The vacuum line will have zero vacuum if the carburetors are right and the engine is supposed to idle at base timing and yours is tuned for advanced timing. Disconnect and plug the vacuum line and rotate the distributor counter-clockwise so the end of the advance can moves maybe 1/2". That will advance the timing enough you you can set it with your timing light. Then it's time to figure out why your carburetors are open far enough to expose the ported-vacuum orifice.
'61 140 PG Rampside
'66 Rear Alum V8 4-dr
'60 Monza PG coupe (sold, sniff, sniff)
'66 Corsa Fitch Sprint Conv. (First car 1971, recently repurchased)

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Re: Powerglide

Unread post by bbodie52 » Sun Sep 03, 2017 8:19 pm

Munypit wrote:Sun Sep 03, 2017 4:56 pm

This is unit that was in car when I bought it... I've attempted to check
Timing, but if I remove vacuum line and plug it the car will barely start and will not stay running
So much for the theory about a Pertronix Ignitor II causing your problems… It looks like you are running the original Pertronix Ignitor. You might check the voltage source that powers the Pertronix unit. It likes to have a full 12 V DC as its power source, and some people make the mistake of simply tapping off the ignition coil positive terminal — forgetting about the ballast resistor wire in the circuit that reduces the voltage down to a nominal 7 V DC. You may find that the ballast resistor wire in the wiring harness has been bypassed, which would provide the correct voltage for the Pertronix electronic module and likely the correct voltage for an aftermarket high-performance ignition coil.

Now as to your comment about the car barely starting and will not stay running with the vacuum advance disconnected. That is not right!

First question: is the vacuum hose connected to the vertical vacuum tube on the carburetor, or is it plugged into the horizontal vacuum tube? The vertical tube is the correct one — known as the spark port. With the engine idle properly set, the spark port is not exposed to manifold vacuum with the engine idling. The spark port is only uncovered and exposed to intake manifold vacuum as the throttle butterfly begins to open. This activates the vacuum advance at partial throttle, long before the engine is turning fast enough to bring the centrifugal advance online.

If the vacuum advance is incorrectly connected to the horizontal carburetor vacuum tube, the vacuum advance unit will be exposed to full manifold vacuum at all times — even when the engine is idling. That would force the vacuum advance unit into a fully advanced position at idle. Under these circumstances, the basic timing setting would be way off — probably set at an extreme retarded setting at idle to compensate for the impact of a fully advanced but unnoticed vacuum advance unit. Try leaving the vacuum advance disconnected and the hose plugged and manually advancing the distributor enough to get the engine started. Then reset the timing using a timing light with the vacuum advance disconnected and the engine idling at less than 700 RPM. That way you are setting the base timing with no impact from the vacuum advance and the engine idling slow enough to prevent the centrifugal advance from having an effect. With the ignition timing properly set and the idle speed properly set, and the vacuum advance still disconnected, you may find that the engine will idle correctly and that you are able to shift the transmission into DRIVE without stalling the engine. If the settings do check out then you need to find out why your vacuum advance was fully engaged with the engine only running at idle speed.

Another possibility might be that your carburetors are not synchronized and that the engine was idling only from the right carburetor, with the idle speed setting holding the throttle opened excessively to compensate for a lack of contribution from the left carburetor. Corvair engines are occasionally found to have been adjusted improperly to compensate for a faulty carburetor, leaving the engine idling on only three cylinders. If this is true it might explain why the vacuum advance was fully engaged at idle, because the right carburetor may have had the throttle opened excessively by the idle speed screw to keep the engine running if it was only idling based on the right carburetor in the right three cylinders. If the throttle is held opened excessively the spark port may be exposed to too much engine intake manifold vacuum, which could force the vacuum advance into the full advanced position. (I'm assuming that the vacuum hose was found to be connected to the vertical spark port tube. The horizontal tube is intended for connection only to the vacuum break choke mechanism).

You may want to recheck the basic starting settings of the idle mixture and idle speed screws on both carburetors. The shop manual procedure utilizes a strip of paper between the idle speed screw and the throttle linkage so that the mechanic can feel when the paper is just released as the screw slowly backed away from the throttle linkage. This establishes the initial contact point (the main cross linkage should be disconnected temporarily to establish the setting). Once initial contact point of the idle speed screws established, the screw should be tightened clockwise 1½ turns to establish the initial idle setting. (Primary carburetor synchronization procedures start on page 6-5 of the attached shop manual section).

If there is a problem with either carburetor idle circuits you may have difficulty adjusting the idle speed using the procedures in the shop manual. If you discover carburetor problems you should not adjust one carburetor to compensate for the other. The faulty carburetor must be corrected to establish a proper idle speed setting. A UniSyn gauge is also useful for synchronizing the carburetors, as it actually measures the airflow volume through each carburetor throat, to ensure that both carburetors are contributing equally to the engine idle.

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All of the above are just guesses — but the symptoms you describe of the engine stalling when shifted to DRIVE and the engine unwilling to start or continue running with the vacuum advance disconnected seems to point to a problem with the basic idle settings and carburetor synchronization adjustments that could be the root of your problem. The behavior of the vacuum advance when disconnected and the engine continually stalling with the transmission shifted to DRIVE are both symptoms of a tuning problem that needs to be corrected.

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Click on the following link for additional material on tuning procedures and using the correct sequence when tuning your engine…

:link: viewtopic.php?f=80&t=13339&p=92065&hilit=video#p92065

:chevy:
Attachments
1965 Corvair Chassis Shop Manual - SECTION 6 - ENGINE TUNE-UP.pdf
1965 Corvair Chassis Shop Manual - SECTION 6 - ENGINE TUNE-UP
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Munypit
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Re: Powerglide

Unread post by Munypit » Thu Sep 07, 2017 6:56 pm

UPDATE: Finally got timing set, although it was at 800 rpm. Engine still stalls when put in,gear.
I failed to mention in original post that the car had not been started in over 18 months. Have went through fuel and vacuum system. Seems like the carbs are in need of cleaning and rebuild.
Have ordered rebuild kits , so it may be some time before I can give another update. Thanks for your info and help.

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Re: Powerglide

Unread post by Munypit » Thu Sep 07, 2017 6:56 pm

UPDATE: Finally got timing set, although it was at 800 rpm. Engine still stalls when put in,gear.
I failed to mention in original post that the car had not been started in over 18 months. Have went through fuel and vacuum system. Seems like the carbs are in need of cleaning and rebuild.
Have ordered rebuild kits , so it may be some time before I can give another update. Thanks for your info and help.

Munypit

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Munypit
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Re: Powerglide

Unread post by Munypit » Sat Sep 09, 2017 10:41 am

Munypit wrote:UPDATE: Finally got timing set, although it was at 800 rpm. Engine still stalls when put in,gear.
I failed to mention in original post that the car had not been started in over 18 months. Have went through fuel and vacuum system. Seems like the carbs are in need of cleaning and rebuild.
Have ordered rebuild kits , so it may be some time before I can give another update. Thanks for your info and help.

Munypit

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Finally got around to removing plug wires from left Bank with engine running. Absolutely no effect on idle. Did see spark from wires. This sorta confirms that left carb not functioning properly. Awaiting arrival of rebuild kits.


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cnicol
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Re: Powerglide

Unread post by cnicol » Sat Sep 09, 2017 7:00 pm

Munypit wrote:
Sat Sep 09, 2017 10:41 am
[/URL]
Finally got around to removing plug wires from left Bank with engine running. Absolutely no effect on idle. Did see spark from wires. This sorta confirms that left carb not functioning properly. Awaiting arrival of rebuild kits.


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[/quote]

Craig cautions: The business of removing plug wires to check firing is S.O.P. for cars with points but doing this on an engine with electronic ignition is a recipe for module failure. The procedure for cars with electronic ignition is to use one of those "ice pick" style test lights. Connect the test light's ground clip to a good engine ground and slip the test light's tip between the spark plug wire boot and HT cable on the distributor. Advance the probe until it contacts the metal wire terminal. Usually this is about 1/4" in.

Shorting out the HT voltage safely drains it to ground. When you simply remove a wire from the distributor, the unloaded coil goes to maximum voltage (25k volts give or take) and that voltage is on the hunt for a place to go. If even a percentage gets into the module, it's instantly toast.
'61 140 PG Rampside
'66 Rear Alum V8 4-dr
'60 Monza PG coupe (sold, sniff, sniff)
'66 Corsa Fitch Sprint Conv. (First car 1971, recently repurchased)

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