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Discussion Starter · #1 ·
Just bought a 65 4 door. Has a 250 swapped in it with a 4 speed. For the carb setup it has an offenhauser 3x1 but carbs are not good. My question is should I replace the carb and intake or is it a pain to tune 3 carbs if I replace them?
 

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Reading your plugs is imperative. While jetting may seem straightforward and tuning for idle air and the like, depending on the runner length, plenum curves and runner curves as well as plenum and runner volume and condition (floor puddling and laminar flow capabilities) it may be necessary to jet up or down on each carb to get your plugs to match across the engine whether you have brand new carbs, rebuild your own or something like that... You can also augment your tuning and plug reading and use a laser thermometer to help on the exhaust side of things to see variations in temperatures at each exhaust port right on the header/manifold immediately after the exhaust port to make sure each cylinder is working optimally (really need to make sure your ignition system is working, wires and plugs are good, good cap, rotor, vacuum curve/advance, etc.) . You say carbs are not good, what does that mean specifically? Are they just not running well? Are they damaged? Are they full of gunk and cannot be cleaned? If you have a picture of the engine bay (or many from many angles) we may better serve to answer your questions about how to correct the issue.

I've seen people chase a vacuum leak from a gasket or hose and replace tons of stuff and still never get the issue resolved.. $2 hose later... boy were they embarrassed... (ME as a kid...) :p

~Andy
 

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Discussion Starter · #6 ·
They are leaking fuel like crazy and from what I see the only broken things I see on them is where the air cleaners go. I'm just trying to get a sense of how to approach this project. I'm keeping the drivetrain the way it is until I can finish everything else on it like body and interior
 

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Thanks for the pics! For starters, I would install all new plugs and wires, check to make sure you have only a full 12 VDC supplying the coil, remove anything not ignition associated from the coil jumpers and make a clear and concise homerun only from power and to the ignition module at the dist, nothing else should be coming from that coil. Then, see how it all runs. Check the cap/rotor too and make sure the alternator is putting out at least 12.6 VDC to the battery. I see one of the choke horns and air cleaner bridges is broken off of a carb... that could be an issue for an air cleaner but those parts are readily available for ease of replacement. You could easily rebuild all those carbs. Cheap and simple to work on as long as they aren't totally roached...
 

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They are leaking fuel like crazy and from what I see the only broken things I see on them is where the air cleaners go. I'm just trying to get a sense of how to approach this project. I'm keeping the drivetrain the way it is until I can finish everything else on it like body and interior
Where are they leaking fuel from?
 

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I guess I would say leaking from that first gasket in the middle on all 3. If I can rebuild them and keep it cheap I'm all for it. I should of driven it more but it ran ok around the block and on the trailer before I brought it home.
See if you can slightly tighten the screws, cris-crossing the pattern of tightening them little by little. Not too tight, just snug them up a bit. I've had good experience getting leaks to either slow a lot or completely subside. Fingers crossed. As for driving it more, is what it is and be thankful it runs and drives as you purchased a classic!! You'll get there, one screw, gasket and wire at a time my friend!! We all started somewhere (***unless you just bought a trailer queen to show off someone else's hard work posing it as your own, then I got no love for you.. LOL) and we all have our stories and labors of love for our rides. Mine was a total basket-case and still kinda is... Work in progress, but working in the right direction!! :)

~Andy
 

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Plans are to drive it as much as I can lol any work that's done to it is all me. Appreciate the input from everyone. If you have any websites to direct me to so I can rebuild the carbs I would also appreciate.
Take a look on YouTube. Tons of useful (and not so useful) Rochester carb rebuild videos there. Rebuild kits are a-plenty and cheap as rice too! Not all are created equal though so hopefully others here will chime in. @Twinshadows and others would likely be your best bet on advice on those carbs.
 

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Discussion Starter · #13 ·
And then one more thing to identify which Rochester I have, how would I go about that. All I know is holley and edelbrock. Hopefully I can officially start working on this project this weekend
 

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1969 Nova . . 2dr . . Chino Valley,Az USA
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Hi there . . . 65chevy4door . . . and , Welcome to SNS , glad too see & have you here with everyone .

1st - ? . . does your 65 / 250 engine run & DRIVE , right now . . ?

2nd - ? . . are you sure of u'r engine size . . ? ( 230ci or 250ci engine ) .
Check u'r motor ID number ............. on the "PAD" ; just above your fuel pump , to the back side of u'r dist .

picture # 1 . - - showing the Chev L 6 motor I D # location .
......................... look at the 'blue - tape' , above the fuel pump .

Motor vehicle Electrical wiring Vehicle Gas Automotive exterior


# 2. - - clean that "pad off" & write those numbers down .
............. the large numbers = motor I D numbers .
............. the small numbers = VIN # - for the original car (that the motor came in) .

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Then , you MAY have both #'s . . . . or . . . . just the larger #'s (write down any #'s
there . . & post them) .

. . Example . .

F = Flint , Mi - GM engine assembly plant .
07 = month the motor was assembled .
09 = day of the month .

B C = engine I D code .

Find out u'r I D code - - here


NovaResource - Nova Engine Codes

ps = I'm looking for some carb info

jim
 
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65chevy4door . . . .
Then , you also may need a different "oil breather CAP " ........... too let your PCV valve = breathe .
Question is - - - is that front cap (in u'r valve cover) .............. Is That Cap - vented . . ?
You should use a 'vented breather cap = there ' . Your PCV valve will work much better .

maybe like this : using my old 'stock one bbl "Mono-jet" carb . LOOK at the 'Breather cap'



jim
 

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65chevy4door
Welcome to the site and too inline world. Try and find you the right Coil plug connector So you will not have any cross arcing, or you can simply swap to a coil in cap. For the 1b carbs many buy a synchronizing tool , You can find them on Jegs summit . That will also help in tuning the carbs. I have never done the 3 1b carbs But i have done this.
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And yes their is a Dual 4 setup in the back ground on that bench.
 

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Well - - - It's NOT a "Mono-jet" carb (like in post # 16 , on my 69 250ci motor picture) .

They look more like the "Rochester B - BC - BV " type carbs .

You can compare by looking at : where the fuel line goes into the 1bbl carbs . The Mono-jet , fuel inlet
is at the Lower area , of the fuel bowl .
The above pictures in post # 5 - the 4th pic down . . . . . . the fuel inlet is in the Top , attached to the
top carb cover , location .


You need too look for any "carb ( I D ) number " - - on the carb body or the mounting base plate .
At one time - - those BV type carbs , had a small metal tag , attached to one of the float bowl screws.
Look around (any parts in the trunk / glove compartment . . . . ? ? ? ) .

Rochester 1 Barrel B, BC, BV Carburetor Numbers (carburetor-parts.com)

Here's a picture of what u'r carb is similar too . ^ ^ ^ ^ ^ ^ .

I hope this will help , some .

jim


.....
ps .... I'd maybe even remove one of your carbs ( Choose the center carb ) , and look good
for any carb ID numbers .
Also , I have had the cast base plate (the two phillip screws) come loose , and have a vacuum leak .
good time to double check those = two screws are 'tight' .
 
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65chevy4door . . . .. You can see that each END CARB , does not have the "center air cleaner bracket ,
for using an air cleaner (center screw) stud too hold u'r air cleaner onto either outside carb .

They have this type " Air Cleaner Adaptor " ; that could be made too fit your carbs ...............................
because - You Do need too have some type of air cleaner mounted .

Air Cleaner Adaptor for Single Barrel Replacement Carburetors DPC1 (carburetor-parts.com) .

Even if you just add simple 1bbl carb air filters (like back in post # 16 ) .

KISS ..............

jim
 
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