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140 carb linkage - variations in 66-69 design
Posted by: truckin-on ()
Date: September 14, 2020 09:31AM

In the process of sorting the carb linkage out on my '69 140, I came across something I wasn't aware of. Anyone know why this was changed for '68 - due to AIR perhaps?

There are three variants of 140 carb linkage - early 65, late 65-67, and 68-9. There are some marked differences between the 2nd and 3rd designs. Previously I though it was just the spring design that had changed, but not so.

Identification (augmented from a previous post):

- Early 65: Secondary rods have no spring & cross shaft secondary lever has a long, curved slot.

- Late 65-67: Secondary rods each have an exposed, concentric spring. Cross shaft secondary lever is straight and has a single hole for rod, (no curved slot). System includes choke-based secondary lock-out. Secondary carb lever mounts are straight.

- 68-9: Secondary rods each have a concentric spring hidden inside a tube. Cross shaft secondary lever has an off-set on both sides and has a single hole for rod, (no curved slot). System includes choke-based secondary lock-out. Secondary carb lever mounts are off-set toward the primary carbs.

Here are pics of the comparision between the 2nd and 3rd designs. The 3rd design shown has add-on cross-shaft bushings, but you can see the differences in the cross-shaft levers and secondary linkages. Although I didn't measure it, sure looks like the cross-shaft secondary levers are shorter on the 3rd design, which would change the linkage geometry.

My supposition is this change was made because of interference with the AIR system, but as my car has that removed at the moment, I can't be sure.








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Re: 140 carb linkage - variations in 66-69 design
Posted by: 66vairman ()
Date: September 14, 2020 09:54AM

Thanks for the post. I have read about the difference, but this is the first picture of it I've seen

It looks like the 68-69 had the spring action to allow the choke lockout to disable the secondaries, but a revised mechanism to try and prevent shaft binding (and resulting bent up rods) that I've seen the 66-67 cars.

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Re: 140 carb linkage - variations in 66-69 design
Posted by: azdave ()
Date: September 14, 2020 09:54AM

In this thread, I learned what others already knew. The secondary carb lockout linkage parts and the secondary carb top itself went through changes due to the smog pump being introduced and needing more room. Maybe you can review this thread for clues to your own observations about the cross shaft before the experts come on and tell us what the reason was. smiling smiley

[corvaircenter.com]

Dave W. / Gilbert Arizona
65 Corsa 140/4
66 Corsa 140/4
66 Corsa 140/4 w/factory A/C
66 Corsa 455 Toro V8
65 Monza Convertible 110/4
66 Monza Convertible 140/4 A/C
65 Monza 4DR 140/PG w/factory A/C
65 Monza 4DR EJ20T/5



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Re: 140 carb linkage - variations in 66-69 design
Posted by: truckin-on ()
Date: September 14, 2020 11:26AM

Thanks for the link Dave W! Had not see that post on the carb differences.

The lock-out changes and the linkage changes I noted here are certainly all related to the AIR installation.

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Re: 140 carb linkage - variations in 66-69 design
Posted by: Seth Emerson ()
Date: September 14, 2020 10:18PM

My 66 140 style (Probably an AIR motor, Car was sold in California) had the off-set mounting bracket for the passenger side secondary, not the straight one. I was collecting them for a while - I must have 5 or 6, because the offset bracket is needed to clear the larger TSP distributor, as well as the Pro-Billet one I still sell. It can be used, with a little tweaking, with the remainder of the 65 linkage, which is what I prefer. The actual throttle arm (attached to the end of the throttle shaft) on the 66 secondary, was different as well. The road racers who run my distributor with the four Rochesters us that 65 linkage, with the 66 secondary mounting bracket.

Seth Emerson

Check my new Performance Corvair Web site [www.perfvair.com]

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Re: 140 carb linkage - variations in 66-69 design
Posted by: RobertC ()
Date: September 14, 2020 11:44PM

A bit of clarification on cross shafts:

California sold Corvairs have / had an AIR system: 1966 - 1967 (140 special order?).

I checked an old parts book that I have and it lists the same part number for 66 w 4/1 bbl w AIR as for 68 - 69 w 4/1 bbl.

So, a 66 California sold 140 has the same cross shaft as your 3rd design.



Edited 1 time(s). Last edit at 09/14/2020 11:49PM by RobertC.

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Re: 140 carb linkage - variations in 66-69 design
Posted by: scottymac ()
Date: September 15, 2020 02:47PM

Anyone reading this have a spare RZ code engine (1966 140hp w/factory a/c and standard trans) or case/block for sale? Will travel to buy. Have RM case as partial trade if interested.

Scott
Danville, In.
'65 Corsa basket case
'66 Monza coupe
[corvaircenter.com]

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Re: 140 carb linkage - variations in 66-69 design
Posted by: SteveInMarietta ()
Date: September 15, 2020 03:56PM

So I thought I'd do some more intensive research and try to nail the 140 cross-shaft sequence once and for all (hopefully). Using info from the P&A catalogs (notoriously unreliable), but also assembly manuals and engineering drawings, this is what I find:

3867200 was the first cross shaft introduced for the 140 HP engine and had the slotted secondary card actuator levers.

3873988 was the cross shaft with the flat levers and superceded 3867200 in mid-'65. According to the 1966 661A parts catalog (Canada) 3867200 was used through 1965 job #8651, which I am assuming is the Canadian serial number, placing the switch about halfway through the '65 production year. This cross shaft was used until mid 1966.

3880758 first appears next in the October '65 P&A 34 catalog and was designated only for the '66 140 HP with A.I.R. This was the cross shaft with the small bent levers. But during the '66 production year this cross shaft also superceded 3873988 and was used for all 140 HP engines into the 1967 production year.

3905981 replaced 3880758 in the middle of the '67 production year and used through '69. This cross shaft is almost indistinguishable from 3880758 and has small bent levers.


Steve

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Re: 140 carb linkage - variations in 66-69 design
Posted by: truckin-on ()
Date: September 15, 2020 08:25PM

Steve - thanks for the research - learned more about this than I could have imagined!

Any idea what the difference is between 3905981 and 3880758? "This cross shaft is almost indistinguishable from 3880758 and has small bent levers."

If I recall, there were some changes in the AIR system between the California AIR cars and '68/'69, so perhaps it was due to that?

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Re: 140 carb linkage - variations in 66-69 design
Posted by: RexJohnson ()
Date: September 16, 2020 09:18AM

The AIR system changed somewhere in the '67 model year. I can't think of anything with the changes to the plumbing that would require the throttle linkage to be changed.

RJ tools
Salem,Oregon

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