Author Topic: I need help identifying Rochester 2GV carb.  (Read 10677 times)

MyRed67

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I need help identifying Rochester 2GV carb.
« on: January 16, 2009, 04:43:32 AM »
   I have located a carb, I believe is correct for my car, but it is missing the tag.   Is there any other way of identifying it?   I am told this carb. came off of a '67 Chevy II with a 283 and a Powerglide, which would have used the same carb. as my 327 - 2 bbl. with a Powerglide.    I have a Car&Parts Catalog of Chevy V-8 Engine Casting Numbers, and from other research I have done I believe this carburetor is either a 7027110 or 7027114, and I believe this would be the correct carb. for my car.  The original stock air cleaner was on the car.   I have a '67 Camaro Coupe that came with the standard 327 2bbl. / 210 hp. with a Powerglide trans. built first week of Nov. '66.    When I got the car, and before I learned how to do much, research it came with a newer intake and carb., which I have since learned came off of a '72 Chevy(was used on several models).   From all pictures I have seen, I would guess it is indeed the right carb. for my car, it has a brass elbow with a PVC Valve coming out of the center of the back of the Base Plate.   The Bore in the Base Plate actually measures 1 3/8",  I found a number on the bottom of the Fuel Bowl   703 1734 (the first 7 is lager than the other #'s) does this # have any meaning?   Ther is a larger C on the front half of the throttle plates, and a 6 * (6 degree) on the back half.  There is a G-5 on the upper part of the Linkage(Drivers)side of the Fuel Bowl (Main Body).  There is C above the # 33318 on the linkage end of the Throttle shaft.  I don't see any other 3's or identifying marks other than the GM 2 JET and ROCHESTER on top of the fuel bowl.  I think I forgot to mention it does have the Passenger side fuel inlet.  I hope somebody can give me some help on this.   Thanks much!!! ???  Mike
1967 Camaro  LOS  11A
Original Engine   Z - Tribute
Mike C.    NW - Illinois

rich69rs

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Re: I need help identifying Rochester 2GV carb.
« Reply #1 on: January 19, 2009, 05:15:27 AM »
One of the main differences between Rochester 2GV carbs was the use of the "hot idle compensator" feature found on Rochester 2GV carbs designed to be used with factory A/C.  If the application was a non A/C car, then the carb did not incorporate the hot idle compensator.  So, for your application, be sure you find a 2GV either with or without the hot idle compensator depending on whether or not your car has A/C or not.

A Rochester 2GV with the hot idle compensator feature is easy to identify by looking at the back (firewall) side of the carb as described in the following from Carburetor Models 2G, 2GC, 2GV Service Manual 9D-3, May, 1973:

During prolonged idling in heavy traffic in hot weather, under-hood temperatures can exceed 200 degrees Farenheit causing severe percolation or boiling of fuel in the carburetor float bowl.  With excessive heat, all fuel vapors cannot be eliminated through normal venting and some will be drawn into the carburetor bore and intake manifold resulting in over-rich idle mixtures. The rich mixture causes a rough idle and may even cause engine stalling.  The Hot Idle Compensator is used on some 2G carburetor models to off-set the enriching effects caused by these excessive fuel vapors by supplying additional air to the intake manifold when idle air/fuel mixtures become rich due to temperature increase.  The compensator consists of a thermostaticallycontrolled valve usually mounted in the area above the main venturi or at the rear of the float bowl. The valve closes off an air channel which leads from above the carburetor venturi to a point below the throttle valves.

The compensator valve is operated by a bi-metal strip that senses temperature. At a certain predetermined temperature, when extra air is needed to off-set the enriching effects of fuel vapors, the bi-metal strips bends and unseats a valve which uncovers the air channel leading from the carburetor venturi to below the throttle valves.  At this time, just enough air is added to the engine
to offset the richer mixtures and maintain a smooth engine idle. When the engine cools and the extra air is not needed, the bi-metal strip closes the valve and operation returns to normal mixtures. Hot idle compensators are pre-set at the factory and require no adjustment. However, to insure proper idle adjustment, the valve must be closed when setting engine idle speed and mixtures. This can be done by using a screwdriver to press down lightly on the valve for those models with the valve located in the main venturi
area. On those models with the valve located at the rear of the float bowl, hold spring-loaded button "in" when making the
idle settings. If no button is available, remove idle compensator cover and using a screwdriver, press in lightly on the valve when making idle settings.  Replace cover after completing idle adjustments.


Over the years, this is the type of distinction that has gotten lost when you go down to the local parts store and try to find a "correct" replacement carb.  GM/Chevy designed variations depending on application and options.  Now you will get "the one size fits all" story from the local parts house, assuming that they even offer a "replacement" carb.  Clearly, "one size fits all" was not how GM/Chevy designed it.

Other than that, if there is no part number stamped on the carb (either on the body itself or on a metal tag attached to the center front air horn screw), it is going to be very difficult to determine exactly what you have.
Richard Thomas
1969 RS

Marty

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Re: I need help identifying Rochester 2GV carb.
« Reply #2 on: January 19, 2009, 11:25:07 PM »
I have a Delco Rochester book with all the datasheets for the Rochester carbs from 1932-1968. Look over the carb and if you find any part numbers that are cast into it or even on linkage pieces post them and I'll check the drawings and parts list.

Martin
Martin Foltz
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68 Van Nuys Camaro

MyRed67

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Re: I need help identifying Rochester 2GV carb.
« Reply #3 on: January 20, 2009, 07:12:14 AM »
Thanks Marty, I have done some more research, from all pictures I have seen; here on this website in the carburetor section, Motorbooks Workshop-Camaro Restoration Guide, and drawings in the 1967 Camaro Factory Assembly Instruction Manual (as well as some others)this carburetor has all the appearance of the correct carburetor for my car.   The picture they show in Carburetor section, showing a picture of the #- 7027116 - Rochester 2GV with a M6 DA date tag looks exactly like the one I have(minus the tag.  It has the side Fuel inlet and the Dist. Vacuum advance fitting in the proper places on the Pass. side.    As for #'s; there is a 703 1734 on the bottom of the fuel bowl (the first 7 is larger than the other #'s)   On the drivers side of the fuel bowl there is a C 5 just below the Pump shaft and Lever assy.  There is a small C 33318 stamped on the end of the Throttle shaft(Drivers side)  There is # - 26469 on the bottom of the bend on the Choke shaft lever(Choke side)  There are some 3's going around in a circle on the back of the Choke pull-off, looks like 8BC104, I'm not exactly sure where this # should begin or end.  It has the correct Thermostatic type Choke.   My car does not have A/C, and there is not a Hot Air Idle Compensator on this carb. as far as I can tell, there is nothing on the back(firewall side) of the carburetor as described above.  The only things on the back of the Carb. are the Vacuum hose for the Choke Pull-off and a Brass elbow with a PCV valve coming out of the middle of the Base plate.   I hope maybe some of this info. helps you and/or me.   Thanks a bunch for any help!   Mike
1967 Camaro  LOS  11A
Original Engine   Z - Tribute
Mike C.    NW - Illinois