Rochester 2GC Bowl Overflow Problem

[M1842]

Wondering if the pressure regulator solved the problem and if the best scotch and cigar were consumed?

[Machine Gun]

25 minutes ago, M1842 said:

Wondering if the pressure regulator solved the problem and if the best scotch and cigar were consumed?

So far so good. I've not a recurrence of the issue in the few weeks since I installed the regulator and set it at 5 psi. I'm pretty cautious about declaring victory just yet. I'll give it another week or so. I did have my favorite cigar (Liga Privada Papas Fritas) but I'm holding off on the scotch for now (Balvenie 14 Caribbean Cask). I have plenty of other stuff to drink.

Edited August 4, 2022 by Machine Gun (see edit history)

[rodneybeauchamp]

Interesting read in this topic and glad the problem was diagnosed. 
 

My thoughts were if a bypass filter system as used on early Buick Riviera was installed would this resolve the issue rather than the regulator. This system was used on AC cars to prevent Vapor lock. The dual outlet can style filter would bypass any excess fuel back into the tank.

 

Would this reduce the pressure enough so it does not overwhelm the float needle by bypassing back to the tank. 
 

I realise the AC cars had the full return line but on a NON AC CAR could it just be teed back into the supply line BEFORE the fuel pump. Basically recirculating the excess fuel.

 

My theory and solution may not work but would be interested to hear what others think.

Rodney 😀😀😀😀😀😀
 

PS Photo kindly suppled by eBay 😀😀

Edited August 10, 2022 by rodneybeauchamp
Photo (see edit history)

[Bloo]

I have retrofitted that system to other cars in the past when chasing fuel boil problems. It doesn't lower the pressure, or at least it shouldn't in a well functioning system. The spring under the diaphragm in the fuel pump sets that. Back when I was using that trick, I misunderstood what it was for, but it still helped. @carbking has an article on his website somewhere explaining what that third port is really all about. I just went to his site but couldn't find the link or I would post it.

 

Edited August 10, 2022 by Bloo (see edit history)

[Machine Gun]

Good news and bad news. The good news is that enough time has passed where I'm satisfied that the fuel pressure regulator solved my years-old problem. The bad news is that I ran out of Balvenie. Fortunately Bushmills got the job done. Thanks to all who weighed in.

 

[EmTee]

2 hours ago, Machine Gun said:

The bad news is that I ran out of Balvenie.

Well, times are tough... 

 

Glad the fix is working!

[Ben Bruce aka First Born]

7 hours ago, Machine Gun said:

Good news and bad news. The good news is that enough time has passed where I'm satisfied that the fuel pressure regulator solved my years-old problem. The bad news is that I ran out of Balvenie. Fortunately Bushmills got the job done. Thanks to all who weighed in.

 

Bush is an improvement!

 Ben

[Machine Gun]

6 hours ago, Ben Bruce aka First Born said:

Bush is an improvement!

If one day we have the pleasure of meeting, remind me that I owe you an argument 😜

Edited August 14, 2022 by Machine Gun (see edit history)

[Ben Bruce aka First Born]

12 hours ago, Machine Gun said:

If one day we have the pleasure of meeting, remind me that I owe you an argument 😜

Challenge ON!   Warning!   I am hard to convince.   May take several trys. 

 

  Ben

[Machine Gun]

The overflow problem recurred this morning. I surrender. One of two things will happen: I will man up and live with it, or I will replace the carburetor with a new aftermarket unit like a Holley. While I genuinely appreciate all of the suggestions offered to date, I'm not looking for additional suggestions. Seven years, two carbs, two rebuilds, and a fuel pressure regulator later, I'm done with this. At least I didn't waste a shot of Balvenie on it.

[Ben Bruce aka First Born]

2 hours ago, Machine Gun said:

The overflow problem recurred this morning. I surrender. One of two things will happen: I will man up and live with it, or I will replace the carburetor with a new aftermarket unit like a Holley. While I genuinely appreciate all of the suggestions offered to date, I'm not looking for additional suggestions. Seven years, two carbs, two rebuilds, and a fuel pressure regulator later, I'm done with this. At least I didn't waste a shot of Balvenie on it.

 

 HAH!   Tried your Balvenie!   Stand by my first comment!😁

 

 Ya want that thing to RUN?   NOT suggesting, now , just saying.    Try AFI !

 

  Ben

[old-tank]

1 hour ago, Ben Bruce aka First Born said:

 NOT suggesting, now , just saying.    Try AFI !

I knew that was coming...Ben, do you have a link to a specific unit for that 2bbl manifold?

Seriously, get rid of that slobbering carb before you and/or the car end up as crispy critters.

[60FlatTop]

4 hours ago, Machine Gun said:

, I'm not looking for additional suggestions.

From my experience that comment is right next to incomprehensible in the Big dictionary. Ironic that it goes right along with "All I want to do is vent!"

[Ben Bruce aka First Born]

2 hours ago, old-tank said:

I knew that was coming...Ben, do you have a link to a specific unit for that 2bbl manifold?

Seriously, get rid of that slobbering carb before you and/or the car end up as crispy critters.

😁😁

 I don't know how to do links.  Here is the web site for the one I use.

 

  www.affordable-fuel-injection.com

 

  Not a huge company.   Holley has one that uses a throttle body that looks like and is the same size as the 2GC and allows the use of the original air cleaner if one wants.

 

  Ben

[Machine Gun]

5 hours ago, 60FlatTop said:

From my experience that comment is right next to incomprehensible in the Big dictionary. Ironic that it goes right along with "All I want to do is vent!"

What's incomprehensible about my statement? You seem to have figured it out: "All I want to do is vent!" Mission accomplished. "Veni, vidi, venti."

 

Just go clarify...I'm not wanting any new suggestions on what to do with my 2GC. I'm done messing around with it.

 

6 hours ago, old-tank said:

Seriously, get rid of that slobbering carb before you and/or the car end up as crispy critters.

That's the plan.

Edited August 21, 2022 by Machine Gun (see edit history)

[NTX5467]

As mentioned, Holley has recently unveiled a family of Sniper EFI 2bbl replacement units.  Self-learning, they claim.  Might even handle the ignition system, too.  BUT most of those aftermarket EFI systems need a distributor of a particular style, which might also dictate the use of an electronic voltage regulator unit, too.  Careful installation can probably hide many of the additional wirings and such, too!

 

Enjoy!

NTX5467

[NTX5467]

The "vapor separator/fuel filter" SHOULD let any expanding fuel in the fuel line, before the needle and seat, to be sent back to the fuel tank.  Just putting that fuel back into the supply line will not help things, unless THAT fuel is forced back to the tank in the main fuel line.  So that "return fuel" needs to go all the way back to the tank with some sort of return line items.

 

Under the return line fitting (on the output side of the "vapor separator/fuel filter") is a drilled orifice of a particular size.  Small enough to keep the carb supplied, but big enough to send the rest of the fuel/vapor mix back to the tank for re-cycling.

 

Enjoy!

NTX5467

[Aaron65]

Maybe you've tried this (and I hate throwing parts at a car), but have you tried another fuel pump?  If you're worried about fuel pressure (and you've tried a regulator, which I've had dubious luck with in the past), it might be worth the money before making a more drastic change.  

[EmTee]

I hate to mention this, but if you're considering TBI, depending upon the system you're considering you may need to add a return line to the tank anyway.  If so, you could simply make that update first and leave the carb in place for awhile.  If that eliminates the problem then you may not need to go so far as adding EFI...

[Machine Gun]

@Aaron65Fuel pump is new, along with a regulator that is set to maintain proper fuel pressure into to the carburetor (5 psi). The full saga can be found further up in this thread.

@EmTeeI looked into TBI systems and decided that it's too big a job for me to complete before I leave for my Route 66 trip next month. Besides, I'd prefer a more economical solution, something like modern Holley carburetor. I've got one picked out, but I need to wrap my head around the concept of an electric choke. I've already read many of the pros, cons, and horror stories associated with them. Still, that would be preferable to the possibility of one day driving down the road in a rolling bonfire. To date I've never experienced the overflow problem at any time other than at first startup, but I can't help but wonder if it could someday occur while driving. Worst case I'd install a manual choke. if the electric gives me fits. Anyway, a new carb is #1 on my list, but I'm not ready to pull the trigger on one until I convince myself that I'm done overthinking all this.

 

As for a fuel return line, I'm not sure how that might help. I'm not being dismissive of the suggestion, just wanting to understand what it could do. I will do some research this evening.

[EmTee]

20 minutes ago, Machine Gun said:

As for a fuel return line, I'm not sure how that might help.

I think it would help avoid too high fuel pressure.  The deadheaded regulator you have is not foolproof; a flow-through regulator would be much more likely to perform reliably (I think...).

[Machine Gun]

I continue to ruminate over what my next step will be. Adding a return to my deadheaded system will be simple enough. Based on information contained in the factory parts catalog, a fuel return system was used on '64 Skylarks only for A/C-equipped cars. The fuel pump and fuel tank were the same for both systems. The only differences were the fuel filter that had a return fitting, the tank sending unit that had a return fitting, and of course the addition of a return fuel line. If I go that route I could keep the regulator, swap out the fuel filter, and add a return line. Seems pretty straightforward. It may be worth a try. Even if it doesn't solve my problem, having a return to guard against vapor lock can't be a bad thing (not that I've ever had a vapor lock episode on that car).

 

Is this thread beginning to read like the script of a cheap soap opera, or is it just me? 🙄.

Edited August 21, 2022 by Machine Gun (see edit history)

[EmTee]

3 hours ago, Machine Gun said:

Is this thread beginning to read like the script of a cheap soap opera, or is it just me? 🙄.

I can hardly wait for the next episode! 

 

[NTX5467]

Which new Holley carb are you considering?  Why will it be better, other than "new"?

 

Just curious,

NTX5467

[Machine Gun]

27 minutes ago, NTX5467 said:

Which new Holley carb are you considering? https://www.summitracing.com/parts/hly-0-80350

 

Why will it be better, other than "new"?

 

I don't expect that it will be better. I'm hoping that it will be better. "Newness" doesn't enter into the equation. That would be a pretty shallow reason for the expenditure, and I like to think I'm capable of more rational analysis. My principal rationale for considering the candidate carb is because it's spec'd to tolerate higher fuel pressures (up to 7 psi vs 5 psi for the 2GC), and therefore might better handle pressure surges that a deadhead pressure regulator might present under varying load conditions.

I've made no decision at this point as to what my next step will be. A new carb and adding a fuel return are the two options currently under consideration. When in doubt, I do nothing. Still thinking...

Edited August 22, 2022 by Machine Gun (see edit history)

[NTX5467]

The reason I was inquiring is that I know of ONE Holley 2bbl that might be a bolt-on for the intake manifold.  It is the 2210 family which Chrysler started using in the 1970 model year.  A great and responsive carburetor, but it has one issue related to excessive torque on the air cleaner wingnut.  Other than that, adapting the linkage to what is on your car.  Plus the divorced choke on it, too.

 

Other than that, a 500cfm 4bbl would be the next option, which would be a lot of changes and some throttle linkage adaptations.  Plus the aluminum intake manifold.

 

Possibly a Rochester 2GC from a slightly newer model year?  As long as the throttle bore size matches the one on your car.

 

IF the needle is sticking to the "seat" in the carb, perhaps some doses of Marvel Mystery Oil (as a lubricant added to the fuel) might help to diagnose the situation, IF that sticking is the issue?  If the sticking is the issue, then both the needle and seat should have some shiney witness areas on them to prove that theory.

 

Perhaps, too, you might decrease the "Float Drop" setting so that the float does not move quite so much when the fuel level drops?  Which might mean the needle would remain more "in the seat" so that it might not cock to one side and stick and not move upward when it needs to, as the fuel level rises again.

 

Just some thoughts,

NTX5467

[Machine Gun]

@NTX5467Funny you should mention a fuel additive. That thought crossed my mind as a possible way to mitigate modern fuel residue, assuming that's what at the root of the issue. When I had the carb apart some weeks ago there was no evidence of needle or seat issues with regard to travel issues or sticky residue after I let it all dry out. Float travel? It's currently set as it should be per the manual, but maybe it needs some tweaking outside the box as you seem to suggest.

 

There are so many possibilities that I could spend a boatload of money and the remainder of my years on Earth trying this, that, and something else. Part of the problem is its intermittent nature, as it can take many weeks before I can know if my latest "remedy" worked. Of the myriad suggestions offered to date, and all seemed reasonable to me, I acted only on the two that made the most sense to me: disassemble and inspect, and reduce the fuel pressure to spec. The only thing I'm confident will put the issue to bed is to convert to fuel injection, but as I indicated earlier I'm not inclined to go that route.

[Ben Bruce aka First Born]

10 hours ago, Machine Gun said:

I've made no decision at this point as to what my next step will be. A new carb and adding a fuel return are the two options currently under consideration. When in doubt, I do nothing. Still thinking...

  That last sentence!   Keeps one from making a LOT of mistakes.

 

  Ben

[60FlatTop]

My comment means it is incomprehensible that you don't want any more suggestions.

[Frank DuVal]

On 8/20/2022 at 4:54 PM, Ben Bruce aka First Born said:

I don't know how to do links. 

Bring up website, use mouse/trackball to highlight the words in the address bar (the words you typed) control C for copy. Then instead of typing the words, do control V for paste. Just as easy as how you  do the quotes in your replies!😉

[Frank DuVal]

On 8/21/2022 at 10:06 AM, Machine Gun said:

regulator that is set to maintain proper fuel pressure into to the carburetor (5 psi).

By a pressure gauge, not just believe the 5 on the regulator,  right?

 

 

If you could borrow a working carburetor that was a drop on replacement, that would be a great troubleshooting tool. It does not even need to be a perfect match performance wise, just bolt on with no modifications so it can be removed after testing. 

Edited August 22, 2022 by Frank DuVal (see edit history)

[Machine Gun]

1 hour ago, Frank DuVal said:

By a pressure gauge, not just believe the 5 on the regulator,  right?

I have a pressure gauge that I used to check pressure before and after installation of the reguator. I did not rely solely on the gauge that I installed on the regulator, although the readings are nearly identical.

1 hour ago, Frank DuVal said:

If you could borrow a working carburetor that was a drop on replacement, that would be a great troubleshooting tool. It does not even need to be a perfect match performance wise, just bolt on with no modifications so it can be removed after testing. 

Good suggestion, but the carb that's now on the car is the second one that exhibited the problem.

[Machine Gun]

5 hours ago, 60FlatTop said:

My comment means it is incomprehensible that you don't want any more suggestions.

I'm sure you've been at a point where you've tried every sensible solution to a problem that just keeps coming back, and you're tired of it all. That's where I'm at now. There is no shortage of expertise on this forum, and I'm grateful that you guys took the time to chime in, share your knowledge, and make suggestions. However, I'm at the point where I think all of the reasonable suggestions have been exhausted. Admittedly I'm not a carburetor expert, but my sense is that there's nothing more to try with my existing setup, at least nothing that won't cost more time and money chasing a long shot. I could very well be wrong, but my gut tells me otherwise.

 

I did come to a decision this morning after a lengthly telephone call with a well-respected carburetor expert, the same old-timer who rebuilt mine two years ago. Think of him as a Carb King, but one who is still in the business of doing rebuilds. After feeding information to him and answering his questions along the way he arrived at much the same conclusion as Carb King and JohnD1956 (and possibly one or two others) did: the problem is most likely related to modern ethanol fuels and the residue they sometimes leave behind when they evaporate, which may have a particular impact on the construction of the 2GC. He admitted that it's just a guess on his part, but it squares with others' suggestions that it's probably fuel-related. So what to do?

 

Let me begin with what I'm not going to do. I'm not going to spend upwards of $600 on a modern carburetor that will probably solve my problem. Likewise I'm not going to spend $1,500 - $2,000 on a fuel-injection retrofit even though it will solve my problem. Instead, I'm going to pre-fill the carburetor bowl with fuel when the car has been sitting for awhile, and then wait for whatever residue may be in there to dissolve and hopefully free the float and/or clean the needle and seat. That suggestion was brought up by others in this thread, and it was also suggested by my carb guy this morning. I'll crank the engine long enough to fill the bowl, stop cranking before the engine fires (or shut it down immediately), have a second cup of coffee, and then go back to the car and start it up. That won't be terribly inconvenient because the problem only occurs after the car has been sitting for at least ten days, often longer, so I won't be a big hurry to get on the road. My sense tells me that's the fix for my 2GC.

Edited August 22, 2022 by Machine Gun (see edit history)