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Need Help - angry smileyThrottle Control Problem
Posted by: BobV66Vair ()
Date: June 05, 2018 09:16AM

I am having fits with my 65 throttle. I had a days help with a club member but still cannot seem to get full WOT on the car. I rebuilt the entire linkages from the tunnel to the carbs. The pedal does not have enough travel to open the throttle. Is it possible the center pivot is on backwards? It is a different length from the pivot center to the front linkage and the pivot center to rear linkage. I am wondering if I have it backwards. I have the short length connected to the pedal and the long length connected to the rear swivel.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: steve c goodman ()
Date: June 05, 2018 09:45AM

From engine with NO front linkage connected do you get full opening with cross shaft only?


Did you remove pedal from shaft?

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: thewolfe ()
Date: June 05, 2018 09:45AM

A little more info...I believe the swivel is fine and on correctly. There is over 2" of travel at the swivel with the rod to the engine bay disconnected. Working the throttle linkage by hand in the engine compartment shows you need less than 2" of travel to get full throttle. The problem is that when the secondaries start to open it requires a significant amount of force to open them and the primaries the rest of the way. Enough that pressing the gas pedal down to the floor we got less than an inch of travel at the trans pivot which tells me there is some flex between the pedal and the pivot. Disconnect the rod to the back and get full travel(over 2"). The pedal gets pretty stiff when the secondaries start to catch which tells me there is binding somewhere or something not setup properly. Bob is also running 4 primary carbs if that makes a difference. Having never worked on a 140 before I'm not certain how all those linkages are supposed to be set but I'm certainly not impressed with the GM design. So my question is how much force does the pedal require to open the secondaries when everything is right?

Nate Wolfe
Portland OR
65 Corsa 180




Edited 2 time(s). Last edit at 06/05/2018 09:49AM by thewolfe.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: MattNall ()
Date: June 05, 2018 10:51AM

BobV66Vair Wrote:
-------------------------------------------------------
> I am having fits with my 65 throttle. I had a days
> help with a club member but still cannot seem to
> get full WOT on the car. I rebuilt the entire
> linkages from the tunnel to the carbs. The pedal
> does not have enough travel to open the throttle.
=============================================================

We had this trouble on Bob Slusher's car when first built...

The gas pedal is on a splined shaft.... Adjust it to get more.





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo




Edited 1 time(s). Last edit at 06/07/2018 06:56PM by MattNall.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: thewolfe ()
Date: June 05, 2018 11:09AM

Matt there is more than enough travel at the tunnel pivot with the rod to the engine compartment disconnected. Connect the rod again and the travel is reduced significantly because of how hard it is to press the gas pedal down once the secondaries engage. You get to that point then the pedal bracket or the rod from the pedal to the pivot is flexing enough to not allow full throttle opening.

Nate Wolfe
Portland OR
65 Corsa 180

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: TerribleTed ()
Date: June 05, 2018 11:14AM

Check the pivot under the rear seat (from the bottom under the left side of the rear tunnel cover). Make sure the bushings are good and that the pivot is solidly connected to the floor (they rust here and sometimes even break completely free) and repair if necessary. There is considerable adjustment at the rear of the accelerator rod that comes out of the tunnel to the pivot at the side of the trans as well as at the throttle rod up to the carb cross shaft. Disconnect the intermediate rod coming out of the tunnel to the trans pivot. Make sure you can attain full throttle at the engine by pulling the rod to full back to full throttle position. If full throttle is not possible because the trans pivot is hitting its stop adjust the clevis at the throttle rod rear ward until full throttle is attained. This pivot should not actually ever hit the stop so adjust so there is some remaining movement before the stop is engaged. Holding the throttle at full throttle (use a spring, helper or whatever to hold it there. Apply full throttle at the accelerator and then adjust the clevis at the throttle rod from the tunnel to enter its hole in the trans pivot. At this point full pedal should yield full throttle. Now you must check and see if the throttle can close fully. Back off the idle speed screws so the crabs can fully close. If the rods will not move far enough back to allow the carbs to close you need to tinker these 2 adjustment so that the carbs can fully close and full throttle is still available. Hope this helps.


Another thought is the possibility of having the incorrect throttle rod from trans pivot to cross shaft installed, or perhaps a bent throttle rod or as Matt suggested a slipped or improperly installed accelerator pedal.


There is an adjustment procedure listed in the 1961 Main book shop manual which is annoyingly and incompletely written but if you have access may help some. I was unable to find 65 manual instructions for accel linkage and or pedal adjustment.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]



Edited 2 time(s). Last edit at 06/05/2018 11:18AM by TerribleTed.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: BobV66Vair ()
Date: June 05, 2018 11:39AM

I am going to try removing the additional return springs on the secondary's. Then see if the pedal will achieve WOT in the engine bay. After that, I'll try tinkering with the adjustment in the sequence Ted suggested. As Nate said, we got the swivel to rotate as far as it would go with the pivot rod disconnected. Then adjusted the pivot clevis so it went into the hole on the swivel. I still think the pivot may be in backwards but I will try the other possibilities first.

FYI, I did replace all of the wear parts on the throttle assembly and reused the same rods that came out of it. The book does not show exactly how that pivot installs so it is possible I got it wrong.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: MattNall ()
Date: June 05, 2018 12:16PM

thewolfe Wrote:
-------------------------------------------------------
> Matt there is more than enough travel at the
> tunnel pivot with the rod to the engine
> compartment disconnected. Connect the rod again
> and the travel is reduced significantly because of
> how hard it is to press the gas pedal down once
> the secondaries engage. You get to that point then
> the pedal bracket or the rod from the pedal to the
> pivot is flexing enough to not allow full throttle
> opening.
============================================================

AHH... no external springs needed.. I've seen several with light springs in the Accel pump Well...setup as internal return springs..

It was 2005...but as I remember we also had to shorten the NEW secondary rod on the 1-3-5 side to get that carb to fully open..ran out of threads for adjustment.





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: RobertC ()
Date: June 05, 2018 12:19PM

Bottom line:

The gas pedal has to be far enough off the carpet (about 3") to be able to achieve WOT.

There a few threads here on the subject...

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: MattNall ()
Date: June 05, 2018 12:21PM

Robert.. this is a racecar...and the Wolfe posted that they have enough pedal travel to fully move the tunnel bellcrank..





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: RobertC ()
Date: June 05, 2018 12:57PM

MattNall Wrote:
-------------------------------------------------------
> Robert.. this is a racecar...and the Wolfe posted
> that they have enough pedal travel to fully move
> the tunnel bellcrank..

Doesn't matter what it is; FIRST: the pedal has to be far enough off the floor; as you know.

Sorry, but, my eyes glazed over with all the conflicting (to me) statements.

Secondary return springs??? (not needed; may use a stronger return spring to the firewall); 4 primaries???

So, what carb linkage is being used?

As noted before:

Accelerator pedal rod bracket can be broken

The tunnel pivot bolt can be rusted / loose

The bushings in the tunnel pivot are bad (There are two bushings that align the pivot arm to the bolt.).

The lever on the transmission pivot arm can be loose.


Otherwise - attention to detail - I think detailed pics are in the assembly manual.

Also, If using the early 65 140 linkage, there is a detent(?) when the secondaries open - from the heavier accelerator pump spring. But, it is not that much (to me - from 30+ years ago).

Have no clue how later 140 linkage feels.



Edited 1 time(s). Last edit at 06/05/2018 01:00PM by RobertC.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: thewolfe ()
Date: June 05, 2018 01:05PM

The pedal is plenty far from the floor. Like 4 inches when we backed all adjustments as far as they would go. Tunnel pivot, bolt, bushings all brand new. The tunnel pivot pivots as far as is physically possible when the pedal is pressed to the floor. Transmission pivot is tight but I also saw it twisting some with the amount of force it was taking once the secondaries start opening. I truly believe the problem is with the linkage/carbs in the engine compartment. Everything else appears to be connected and working fine.

Nate Wolfe
Portland OR
65 Corsa 180

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: steve c goodman ()
Date: June 05, 2018 01:37PM

how much effort is needed to open the 4 carbs using only the cross shaft?

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: RobertC ()
Date: June 05, 2018 02:18PM

thewolfe Wrote:
-------------------------------------------------------
> The pedal is plenty far from the floor. Like 4
> inches when we backed all adjustments as far as
> they would go. Tunnel pivot, bolt, bushings all
> brand new. The tunnel pivot pivots as far as is
> physically possible when the pedal is pressed to
> the floor. Transmission pivot is tight but I also
> saw it twisting some with the amount of force it
> was taking once the secondaries start opening. I
> truly believe the problem is with the
> linkage/carbs in the engine compartment.
> Everything else appears to be connected and
> working fine.

As Steve Goodman stated.

There is a "correct side / position" for the links for the secondaries - from the cross shaft.

If one or both were installed incorrectly, I would think that the linkage would bind.

There should be a pic in the 65 shop manual and / or the 65 assembly manual.

RE the tunnel pivot - was the accelerator rod installed correctly in the pivot?

Ignore my previous babble - a pic is here in Clark's catalog:

[www.corvair.com]



Edited 1 time(s). Last edit at 06/05/2018 02:22PM by RobertC.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: BobV66Vair ()
Date: June 05, 2018 02:22PM

Some notes: Using four primary carbs with relocated jets. Using the 1965 linkages that have a slotted piece that allows the first two carbs to act like a 110 until 3/4 throttle, then the secondary's open. Secondary's open almost on a snap, not progressive. I tried a direct linkage setup that Clarks sells but it was crap. Cheap materials and impossible to adjust to get the carb's working together. I wish there was a better setup but I have not found it yet. Maybe a 66 or later linkage setup? I would go to the Roger Parent linkages if I had the money.


I have been out working on this while the thread continued. Here is where I am at. I believe there is yet another problem but I'll go into that in a minute.

1. I removed the heavy return springs from the secondary's.
2. I put the Clarks return springs on the shafts of the secondary's. NOTE: With no return springs on them, the accelerator pump springs will not close the carb. There is NO return action from the linkage.
3. The pedal is much easier now and it seems to rev to red line. I need a second person to look at the linkages while I stand on the pedal. I'll do that later today when I have a second person.

4. New problem. I started to Sync the carbs using a Unisyn gage. I cannot get the car to idle below 1,500 RPM. Again, hard since I can't keep it running long enough to get from the car to the engine. More help later. For some reason, the carb's surge to high RPM with no input. I verified that they are all fully closed and the RPM's seem to have a mind of their own. It surges up high and stay there. Eventually, it does come down but then it stalls. I have tried setting the idle on all 4 carb's up high enough to keep it idling but it still has the crazy surging action. I think there must be something wrong with the carb's internally. I rebuilt them again right after I had the jets relocated (By Seth). They went together well and seemed to have everything they needed replaced.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: RobertC ()
Date: June 05, 2018 03:43PM

BobV66Vair Wrote:
-------------------------------------------------------
>
> a slotted piece that allows the first two carbs to
> act like a 110 until 3/4 throttle, then the
> secondary's open. Secondary's open almost on a
> snap, not progressive.
>

This is not correct. The stock secondaries have a stronger accelerator pump return spring (sits in the bottom of the well).

You NEED the same spring (not the stock primary accelerator pump return spring) in your "secondaries".

Since you are using the stock early 65 140 linkage. If you had positive linkage to all 4 carbs, it would not be a problem.

I cannot find the spring in Clark's catalog. Maybe Steve Goodman / California Corvairs may have them.

> 2. I put the Clarks return springs on the shafts
> of the secondary's. NOTE: With no return springs
> on them, the accelerator pump springs will not
> close the carb. There is NO return action from the
> linkage.

Again, The stock accelerator pump return spring is what is needed.

Almost sounds like there is no spring in the accelerator pump well.

>
> 4. New problem. I started to Sync the carbs using
> a Unisyn gage. I cannot get the car to idle below
> 1,500 RPM.

Have you set the initial idle speed per the shop manual?

Use a strip of paper between the arm and idle speed screw just makes contact and turn idle speed screw in 1 1/2 turns?

To use the Uni-Syn:

Disconnect the linkage to the "secondaries"; use something to keep the throttles closed (with correct spring they should be closed).

Then, sync the two primaries as you normally would.

Use the Unisyn setting on the two primaries to set the idle speed screw on each "secondary" - one at a time.

Then, reconnect the linkage.

> I have tried setting the idle on all 4
> carb's up high enough to keep it idling but it
> still has the crazy surging action.

Have you looked down the bores to see any excess gas is dribbling down?



Edited 1 time(s). Last edit at 06/05/2018 03:48PM by RobertC.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: 63turbo ()
Date: June 05, 2018 03:57PM

I'm not sure if this is helpful but when I've had problems with Corvair throttle linkages not going wide open, I usually end up setting the pedal
in the car at the wide open position, and set the throttle at the engine at
at the wide open position also, and adjust the linkage in such a way as to
have the floor board be the stop for wide open, and have the throttle stop on
the carb or throttle body stop the linkage when closed. On my 140 I couldn't feel any excessive force to open the secondary's... seemed to work well!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Need Help - angry smileyThrottle Control Problem
Posted by: BobV66Vair ()
Date: June 05, 2018 04:30PM

Robert. Carbs were all built as would be proper for primary or secondary. Pump springs are correct. You said the linkage to the secondary's was not correct but then mentioned the accelerator pump springs. I am not sure I follow why you think the linkage is incorrect. FYI, Clarks does not sell the Accelerator pump return springs but I have several. I do know how to sync the carbs with a 4-primary carb setup. I also know how to set the idle. Neither is my issue.

The RPM drifts way up and then way down. There is no opportunity to set an idle speed since the engine will not stay at any RPM long. All I can think of is there is yet another problem inside the carbs. I hate to rebuild them again since they have less than 100 miles on them. I may do it yet but I was asking for reasons the idle would fluctuate so wildly without any inputs.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: RobertC ()
Date: June 05, 2018 05:04PM

At a minimum, these two statements do not add up:

" Pump springs are correct."

" NOTE: With no return springs on them, the accelerator pump springs will not close the carb. There is NO return action from the linkage."

On a stock 140 (You have one), the accelerator pump return spring holds the secondary throttle plate closed until activated by the linkage.

On a stock 140, the secondary throttle plate gradually opens to any position based on the accelerator pedal. It does not "flip" to completely open.

Good luck.

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Re: Need Help - angry smileyThrottle Control Problem
Posted by: BobV66Vair ()
Date: June 06, 2018 06:38AM

Thanks but without suggestions to fix those issues, I am still without an answer. I'll move forward.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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