66 Monza 4 Carb setup

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Tony11
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Joined: Sat Aug 08, 2020 7:00 am

66 Monza 4 Carb setup

Post by Tony11 »

Hi,
I just looked at the engine bay of my car looks like it was a 4 carb set up from factory and someone took off 2 carbs and put steel plates over them .Should i get 2 new carbs and try and brings it back to original ,does this effect the performance of the engine .In order to bring it back to 4 carb setup i would need all the fuel lines and linkage ,i think ?Any recommendations.It runs ok but shakes at low rpm.Thanks in advance for any one helping.

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terribleted
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Re: 66 Monza 4 Carb setup

Post by terribleted »

To put it back to 4 carbs you would need 2 secondary carbs, fuel lines and at least all the secondary carb linkage parts. Performance increase would be around 20 or more HP at peak, You need to fix your rough idle before even thinking about adding 2 carbs. Is the car a stick shift or an automatic? I would not bother with the secondaries on a automatic. You should check the distributor to make sure the correct one is installed and check the block code to see if the engine is really a 140 engine or a lesser engine with 140 heads stuck on it. Distributor casting number should be 1110330 (stick shift 140) or 1110339 Powerglide 140, or 110371 or 1110454 (140 engines from 1968-69). Vacuum advance should be a #217 or #248.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

Tony11
Posts: 7
Joined: Sat Aug 08, 2020 7:00 am

Re: 66 Monza 4 Carb setup

Post by Tony11 »

terribleted wrote:
Sat Aug 15, 2020 7:43 am
To put it back to 4 carbs you would need 2 secondary carbs, fuel lines and at least all the secondary carb linkage parts. Performance increase would be around 20 or more HP at peak, You need to fix your rough idle before even thinking about adding 2 carbs. Is the car a stick shift or an automatic? I would not bother with the secondaries on a automatic. You should check the distributor to make sure the correct one is installed and check the block code to see if the engine is really a 140 engine or a lesser engine with 140 heads stuck on it. Distributor casting number should be 1110330 (stick shift 140) or 1110339 Powerglide 140, or 110371 or 1110454 (140 engines from 1968-69). Vacuum advance should be a #217 or #248.
Hi
I will check when i get home on the numbers but its stick shift ,where would the block code be ,I tried to check with the vin number but no luck .

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Re: 66 Monza 4 Carb setup

Post by bbodie52 »

I'm sorry the the lengthy amount of material below, but restoring the original carburetor system to what was apparently a 140 hp 4x1 4 carburetor engine can be somewhat complicated, possibly expensive, and with several different approaches available to you. Supporting configuration and maintenance information and illustrations/photos/diagrams are provided below and in the attached technical documents. The 140 hp engine was standard on the 1965-1966 Corsa, and optional on other Corvair passenger cars from 1965-1969. The primary and secondary carburetors remained largely the same over those years, but the secondary throttle linkage was redesigned in mid-1965-1966 to mechanically lock out the secondaries until the engine was fully warmed up and the chokes were disengaged.

You could operate the engine with properly tuned and operational primary carburetors only — leaving off the secondaries with block-off plates installed. This configuration would approximate the 110 hp engine 2-carburetor configuration. The actual 110 hp engine was usually configured with the same camshaft used in the 140 hp engine. The 140 hp engine had different cylinder heads that offered larger valves, larger exhaust ports and exhaust manifolds with somewhat increased volume capability. The 110 hp engine had a single muffler exhaust, while the 140 hp engine was fitted with a dual exhaust system to offer "better breathing" to match the two extra secondary carburetors and the larger valves and intake/exhaust ports in the heads. With only two carburetors, your big valve engine may perform slightly better that the small valve 110 hp engine, but this would be limited by the lack of two secondary carburetors that would take advantage of the added breathing capacity designed into the 140 hp heads and dual exhaust system.

The 140 hp engine usually operates primarily with only the two primary carburetors in operation, while the secondaries remain closed. The driver's driving habits determine how often the secondary carburetors are actually in-use. Driving with a light foot on the gas pedal will provide better gas mileage, but less aggressive performance (essentially like driving a Corvair with a 110 hp or less 2-carburetor engine).

Restoring full intake capacity to your engine would require obtaining the missing secondary carburetors. The difference between the primary and secondary carburetors is covered in the attached DELCO ROCHESTER - Models H, HV Carburetor Service Manual on page 12.

I have included a few sample listings for purchasing replacement carburetors for your engine. Options include buying four used carburetors with linkage, or buying two secondary carburetors — usually without linkage, fuel lines, air filter system, etc. An air cleaner system (stock or after-market custom) would be needed. A complete used linkage could possibly be found, but might be hard to find. Roger parent offers an excellent after-market custom linkage, and I have included an attached copy of his catalog. Electronic fuel injection that is designed for the Corvair is offered in the Clark's Corvair Parts catalog, and its design and description can be found using this link: http://www.corvair-efi.com/. An older approach, dating back to the 1960's, is to install a custom intake manifold to mount a single 4-barrel center-mounted carburetor (approximately 390 CFM capacity). This approach has some tuning issues, and tends to be cold-blooded with poor cold temperature winter operation, since the carburetor is generally isolated from engine heat. This could be a significant problem if you plan to drive your Corvair in the winter in Canada.
This will give you some idea of the differences between the 140 hp engine and the 110 hp engine.

140 hp vs. 110 hp...
  • Same high-performance camshaft on both 140 hp and 110 hp engines. Low performance camshaft in the 95 hp engine.
  • Same 164 Cubic Inch displacement with same bore and stroke on all 1964-1969 engines.
  • Stronger, nitrided crankshaft on the 140 hp and 180 hp turbocharged engines. (Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface).
  • On the 140 hp engine, a 4x1 carburetor arrangement, with two primary and 2 secondary 1-barrel carburetors, connected with a progressive linkage to open the secondary carburetors as you approach full throttle. (Equivalent to a 4 barrel carburetor on the 140 hp engine, vs. a 2 barrel carburetor (2x1) on the 110 hp and 95 hp engine).
  • Dual muffler, dual exhaust with larger exhaust ports and larger exhaust manifolds on the 140 hp engine. Single exhaust on the 110 hp and 95 hp engine.
  • 9.0:1 Compression Ratio in both 140 hp and 110 hp engines. 8.0:1 CR on the 95 hp engine.
140 hp Heads...

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It's all about better breathing at full throttle at the high RPM ranges. At lower RPM the big valves and dual exhaust don't make much difference, and the secondary carburetors are not open for business.


110 hp Heads...

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What are the final two letters on your engine serial number (see sample below for location)?

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VINTAGE 1965 CORVAIR MONZA ROCHESTER CARBURETORS & LINKAGE

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Price:
US $700.00

:link: https://www.ebay.com/itm/VINTAGE-1965-C ... SwR7JfKwrD

eBay item number:133485457282

=========================================================================

Pair of PERFORMANCE Corvair Carburetors modified to use as 140 HP Secondaries!

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Price:
US $399.00

:link: https://www.ebay.com/itm/Pair-of-PERFOR ... SwzMlcbbTV

eBay item number:293065719254
If you are tired of reading a lot of disclaimers attached to ebay auctions, you have finally found one where there are none. This is a PAIR (2) of Upgraded PERFORMANCE Level Wolf Enterprises Corvair Carburetors. You get both for the final bid - one bid, two carbs, not eaches. Please don't ask :-)

These were unique to 1960 engines and are the result of many experiments and modifications over several years to find the best possible parts combination so they can replace the secondary carbs on all 140 HP Engines and give you increased flow and the ability to adjust the idle speed and mixture. They have larger intakes and bowls from late model units so as to give you a power enrichment circuit on all 4 carbs when you need it and a base vent for better hot start conditions. The throttle shafts are trimmed 50% to increase flow even more. The venturi clusters are thinned slightly and the air intake is enlarged and polished. They are jetted at .055", unless you want larger or smaller.

Your new carbs will flow considerably better than stock (up to 15%, depending on your particular set up), and will therefore be more responsive to tuning and engine demand. They include the best gaskets and parts available and set up and adjusted to eliminate most, if not all, synchronization procedures. They have the recently available ethanol-proof viton accelerator pump cups and inlet needles. Unlike others you can purchase, everything on these will be matched and correct for top performance. I am the only rebuilder providing NEW SS accelerator pump levers and plated rods to take up ALL of the slop in your carb linkage system. They will have larger .101" fuel inlet seats with Viton-tipped (ethanol-proof) inlet needles to replace the stock .086" ones. You can trade in your old carbs for a discount of $100.

These will not work on the Spyder 150 and Corsa 180 HP turbocharged engines, but I have that carb for sale in another auction. But, they can be used on after market applications as primary carbs where a choke is not needed or desirable. AND PLEASE, if you have any concerns about delivery time or anything at all, check with me before bidding. I do not post or share questions and answers on eBay for your privacy, so don't be afraid to ask. Thanks for taking the time to read this and for considering Wolf Enterprises, as we will be here to help you out when other part time eBayers and carb rebuilders have disappeared.

Postage costs include insurance. Export orders will be shipped via DHL Express at the same rate as USPS Priority Mail, except you will get 2-day delivery. (eBay doesn't currently offer that as a option to select when listing).
=========================================================================

PERFORMANCE Corvair 1965 - 1969 140HP Carburetors. $200 rebate for Cores!

Image

Price:
US $688.00

:link: https://www.ebay.com/itm/PERFORMANCE-Co ... SwcaFZE8qA

eBay item number:293426263464
This set of 4 matched and tuned Wolf PERFORMANCE carbs will flow much better than stock, and will therefore be more responsive to tuning and engine demand. You WILL have more power. They are made to flow and work the way GM should have made them for a higher performance level of their Corsas. They are similar to the Yenko Stinger carb upgrades while retaining good idle quality, along with the capacity to flow up to 15% more than stock carbs. The intakes are enlarged and polished all the way to the throttle body areas. The thottle body area is enlarged by thinning the throttle shafts by 50%, and the venturi clusters are modified for more flow. They have the best available gaskets and parts, as well as new Ethanol-proof accelerator pumps (newly available) and gaskets. Carbs are set up and adjusted to eliminate most, if not all, synchronization procedures. NEW pump levers and rods are added to take up ALL of the slop in your carb linkage system. The carbs get larger .101" fuel inlet seats with NEW Viton (ethanol-proof) tipped inlet needles and larger main jets. The primary choke shafts are modified, shaved 50%, and re-plated in clear zinc. Special larger SS choke plates seal the larger intakes properly.

There are also several proprietary improvements you will appreciate and they come with a complete set of new 18-8 Stainless Steel Fasteners. I also include a set of 12 SS accelerator fasteners, 8 base gaskets, 4 air cleaner gaskets, vacuum plug, and life time fuel filter screens to improve fuel inlet flow. They will be recolored in OEM tones like the photo (yes, they really did look like this from the factory). Or, you can chose a different color to match your engine or car or whims. I include instructions and tips for an easy installation. They are shipped by insured priority mail for 2-3 days delivery. I will refund $200 for your old rebuildable ones. Export orders will be shipped via DHL for 2-3 day delivery (but use the USPS Expedited rate when you check out).

If you need a good used parts source... you might contact the Corvair Ranch in Gettysburg Pennsylvania. They know a lot about parts substitutions, have a large inventory of used Corvair parts and may be able to help you. Recommend you give them a call to discuss your needs...

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:link: http://www.corvairranch.com/

1079 Bon-Ox Road, ​Gettysburg, ​PA. 17325 USA
​Phone: 717-624-2805

fax us by the same number... ask us to hook up the machine

Email: findit@theranch.today

Our hours are Monday thru Friday 9 to 5, Saturday 9 to 12 or contact us for an appointment.


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:chevy:
Attachments
1965 Corvair Chassis Shop Manual - SECTION 6M - ENGINE FUEL.pdf
1965 Corvair Chassis Shop Manual - SECTION 6M - ENGINE FUEL
(8.87 MiB) Downloaded 14 times
1965 Corvair Chassis Shop Manual - SECTION 6M - ENGINE FUEL 4x1 Carburetors.pdf
1965 Corvair Chassis Shop Manual - SECTION 6M - ENGINE FUEL 4x1 Carburetors
(1.53 MiB) Downloaded 16 times
1965 Corvair Assembly Manual - THROTTLE LINKAGE SYSTEM.pdf
1965 Corvair Assembly Manual - THROTTLE LINKAGE SYSTEM
(1.92 MiB) Downloaded 14 times
1965 Corvair Assembly Manual - FUEL AND EXHAUST SYSTEMS.pdf
1965 Corvair Assembly Manual - FUEL AND EXHAUST SYSTEMS
(2 MiB) Downloaded 13 times
1965 Corvair Assembly Manual - CARBURETOR & FUEL SYSTEM.pdf
1965 Corvair Assembly Manual - CARBURETOR & FUEL SYSTEM
(3.92 MiB) Downloaded 17 times
DELCO ROCHESTER - Models H, HV Carburetor Service Manual.pdf
DELCO ROCHESTER - Models H, HV Carburetor Service Manual
(1.79 MiB) Downloaded 13 times
Roger Parent Catalog 11-02-19.pdf
Roger Parent Catalog 11-02-19
(1.69 MiB) Downloaded 15 times
CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers.PDF
CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers
(1.25 MiB) Downloaded 15 times
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

66vairguy
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Re: 66 Monza 4 Carb setup

Post by 66vairguy »

Tony11 wrote:
Sat Aug 15, 2020 6:49 am
Hi,
I just looked at the engine bay of my car looks like it was a 4 carb set up from factory and someone took off 2 carbs and put steel plates over them .Should i get 2 new carbs and try and brings it back to original ,does this effect the performance of the engine .In order to bring it back to 4 carb setup i would need all the fuel lines and linkage ,i think ?Any recommendations.It runs ok but shakes at low rpm.Thanks in advance for any one helping.
T Ted gave excellent advice. BTW - the 140HP PG (automatic) cars had a unique and rare distributor timing curve. It's difficult to find that distributor. I've helped two folks with 140HP PG cars with the wrong distributors by installing the 1965 110HP distributor (1110319). Very similar timing curve. If you have a manual transmission car you'll need the 140HP distributor (1110330) for optimal performance with the secondaries installed.

Bob Helt's "Rochester" carburetor book is a great source of information (See Seth Emerson on corvair center forum). There were different "4 carb" setups, although all were similar. Unless you are experienced with older car carburetor systems you would be wise to find someone with 140 HP experience to help you.

Back in the day a number of folks (and mechanics) pulled off the secondaries and installed the block off plates to make the engines more reliable to drive on a daily basis. Basically you end up with about the same power as the 110HP engine when the secondaries are removed. The secondaries aren't necessary and would only make a noticeable difference at higher RPM. I'm talking about a manual transmission car.

That said, when I suggest to folks a two carburetor engine is fine they always point out I my engines are the 4 carburetor setup. My cars are a hobby and I like the four carburetor setup look at shows and I don't mind the extra maintenance involved.

If you do decide to go with four carburetors stay with the 1965 design and primaries. Roger Parent on the CCF sells an outstanding (and pretty to look at) aftermarket linkage.

Tony11
Posts: 7
Joined: Sat Aug 08, 2020 7:00 am

Re: 66 Monza 4 Carb setup

Post by Tony11 »

Hi
Thanks for the info on this ,I am going to stay with the 2 carb setup and maybe up grade to efi soon ,the last 2 letters on my engine are RD .Please let me know if its the right motor .

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bbodie52
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Re: 66 Monza 4 Carb setup

Post by bbodie52 »

As shown on page 5 of the CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers booklet that i attached to my earlier post, the suffix code letters "RD" indicate that the engine is a 1965-1967 2-carburetor 110 hp Manual Transmission configuration for a Corvair 500 or Monza. If your cylinder heads are original 4-carburetor big valve units (identifiable by the cylinder head casting number on the end of each head), the identification of the cylinder head code numbers can be found listed on page 6 of the same CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers booklet.

Here are sample pictures of the cylinder head casting number. It is often hidden behind engine sheet metal.

Image
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Rarely you will find a small valve early head that has been modified to add two additional carburetors. The picture below shows one type of intake manifold modification kit. The difference between the factory 140 hp engine and a small valve (110 hp or less) is the valve size, which permits more airflow through the combustion chamber to take full advantage of the two additional carburetors. Most 110 hp engines were fitted with the same factory performance camshaft found in the 140 hp engines.
bbodie52 wrote:Early Corvair performance tuners opted for a 4 Rochester carburetor modification that was later adopted by GM engineers in their 140 hp engine. But that engine received improvements and upgrades throughout the cylinder head including larger valves and ports, a better camshaft design, and a dual exhaust system. A comparison between the 140 hp and 110 hp engine cylinder heads is shown below. Both engines shared the increased 164 CI displacement, a 9.0:1 compression ratio, and the same camshaft grind. But the 110 hp engine retained the small valve heads, 2 carburetors, and single exhaust system.

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:link: http://www.corvair.com/user-cgi/catalog ... ow_page=63

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Part number C8607: OTTO 4 X 1 CARB KIT-CHANGES 2 CARB* HEADS TO 4- AIR CLEANER KITS ARE REQUIRED

Weight: 6 lbs 0 oz
Catalog Page(s): 63,OT-18(RM19)
Price: $ 386.35


Image

This will give you some idea of the differences between the 140 hp engine and the 110 hp engine.

140 hp vs. 110 hp...
  • Same high-performance camshaft on both 140 hp and 110 hp engines. Low performance camshaft in the 95 hp engine.
  • Same 164 Cubic Inch displacement with same bore and stroke on all 1964-1969 engines.
  • Stronger, nitrided crankshaft on the 140 hp and 180 hp turbocharged engines. (Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface).
  • On the 140 hp engine, a 4x1 carburetor arrangement, with two primary and 2 secondary 1-barrel carburetors, connected with a progressive linkage to open the secondary carburetors as you approach full throttle. (Equivalent to a 4 barrel carburetor on the 140 hp engine, vs. a 2 barrel carburetor (2x1) on the 110 hp and 95 hp engine).
  • Dual muffler, dual exhaust with larger exhaust ports and larger exhaust manifolds on the 140 hp engine. Single exhaust on the 110 hp and 95 hp engine.
  • 9.0:1 Compression Ratio in both 140 hp and 110 hp engines. 8.0:1 CR on the 95 hp engine.
140 hp Heads...

Image

Image

Image

It's all about better breathing at full throttle at the high RPM ranges. At lower RPM the big valves and dual exhaust don't make much difference, and the secondary carburetors are not open for business.


110 hp Heads...

Image
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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