Machine Gun

Opinions Sought on Delco-Rebuilt Carburetor

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My '64 Skylark V8 has a Rochester 2GC that was installed by the previous owner. It's one that he got from one of the auto parts store chains and was rebuilt by Autoline. It wasn't working right when I got it, and although I got it working fairly well right now, it has some issues that have been annoying me for the past four years. I was thinking of sending it out to a reputable rebuilder, but the core is pretty messed up and so I want to replace the whole works. There's a Delco-rebuilt unit for sale that I'm thinking of picking up. By "Delco-rebuilt" I mean that it's in a Delco box and has a Delco tag on the bowl that says it was rebuilt for GM by an independent rebuilder. It's been on the shelf for years, so are there any words of caution about buying a rebuilt carb that's been sitting for decades, apart from perhaps dried out accelerator pump leather?

 

Jim

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 Jim, I cannot answer your question  .  I will make a suggestion.  If you drive this car a lot, install an EFI.  The after market ones are all pretty much self contained.  Almost unnoticeable with the air cleaner on. Completely reversible.  I did this 12,000 miles back on my '50 straight eight. With today's gasoline being formulated for FI, no way I would go back for a driver.  0 degrees?  No problem. Starts right up.  110 degrees? Same thing. No stuttering, no stalling.  

 

  Try it. You will like it.

 

  Ben

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If you buy an older rebuilt carburetor, HOPE that it has a leather accelerator pump. If it does, a few drops of light machine oil, and good as new. If it is synthetic, and more than a couple of years old, it will not hold up in E-10.

 

The only reason Rochester went to the synthetic pump was cheap. Carter never did.

 

Jon.

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5 hours ago, Ben Bruce aka First Born said:

 

 Jim, I cannot answer your question  .  I will make a suggestion.  If you drive this car a lot, install an EFI.  The after market ones are all pretty much self contained.  Almost unnoticeable with the air cleaner on. Completely reversible.  I did this 12,000 miles back on my '50 straight eight. With today's gasoline being formulated for FI, no way I would go back for a driver.  0 degrees?  No problem. Starts right up.  110 degrees? Same thing. No stuttering, no stalling.  

 

  Try it. You will like it.

 

  Ben

I am not familiar with these units.  Is there one you'd recommend?

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I'm not sure who "Autoline" is, but I've seen some decent reviews in other forums.  Doesn't mean it "as good as new", though, to me.  Depending upon the rebuilder, the quality of the items used in the rebuild can be variable in quality and durability.  AND at a price that can allow the auto supply chains to make a good profit on them.

 

How is your existing rebuilt carb "messed up"?  Just curious.  For any rebuilt carb that's been on a shelf for many years, it might work when installed and it might not.  As mentioned, it could have some issues when it's been exposed to current ethanol-blend fuels, too.  So it can be a "crap shoot", of sorts.

 

Ben makes a good point about modern fuels and how they get into the engine.  Only thing is that a higher expense is involved, parts and LABOR, that might not be financially-returned in fuel savings alone, IF that matters.  The other side of things is that when the Rochester 2bbls from the '60s and earlier '70s are "to spec", they are bulletproof in drivability and durability.

 

When we first got RFG in TX, I was driving an inherited '70 Skylark Custom 350 2bbl V-8.  I could document a 3% fuel economy decrease, as Chevron had stated on their website, in a section buried deep in the back of their website, devoted to ReFormulatedGas, at the time.  No performance issues, so I'd suspect nothing major with E10, personally.

 

In getting one of the older carbs rebuilt, you do NOT want a NewOldStock carb kit!  You want one that's more recent, to which you'll probably need a thick carb baseplate insulator gasket.  Adjust the idle just as you used to, get a new choke coil, or adjust the older one 1-2 notches "lean", as they get tighter with age.  Then do a tune-up on the ignition items.  That should put you in a place that should be "good" for about 10-15K miles down the road.

 

Just some thoughts,

NTX5467

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On the subject of daily driver, throw the heated choke to the side and go electric. Some people complain about them, but I have had zero issue with electric chokes and being in the PNW, I am subjected to every single type of weather possible except for hurricanes and tornadoes of course. I drive my car every month of the year except for when there's 6 inches of snow on the ground.

 

Anything that has been sitting on the shelf for years must always be rebuilt, regardless of what it is, in my opinion. Gaskets have shelf life, too. It's like installing a 20 year old mechanical fuel pump and getting mad it has stopped working after 3 months because the diaphragm ripped.

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14 hours ago, NTX5467 said:

..................................

 

How is your existing rebuilt carb "messed up"?  Just curious.  For any rebuilt carb that's been on a shelf for many years, it might work when installed and it might not.  As mentioned, it could have some issues when it's been exposed to current ethanol-blend fuels, too.  So it can be a "crap shoot", of sorts.

 

NTX5467

 

Same thoughts.

 

These carbs, when properly rebuilt, are good for 100k miles assuming normal maintenance of the fuel and air filters. Some of the more reliable auto parts ever built.

 

Jon.

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Thanx for the replies guys.

 

@Ben: I very much like the idea of EFI, but regardless of the relative merits of EFI over carburetion, my budget won’t accommodate a conversion.

 

@Jon: Whether the older rebuilt has a leather accelerator pump doesn’t worry me too much because I bought a rebuild kit from you about two years ago, so I know that I have a proper leather pump and gaskets out in the garage! See below for what’s up with my carb.

 

@NTX: The carb has been a royal PITA since day one when I got the car. The accelerator pump link on the outside of the carb was missing. It didn’t take me long to figure out why: the accelerator pump was jammed inside the carb. When I took it apart I found that the cheap plastic pump had come apart inside and jammed up the works. I put in a replacement pump and fabricated a link to get it working again. One of the choke hold down screw holes is stripped. The choke release piston won’t break the choke open with engine vacuum when the car starts, even though there’s proper engine vacuum, nothing is binding in the mechanism, none of the passages in the carb are blocked, and the air intake for the choke piston is clear. What I want to avoid is sending the carb out to a reputable rebuilder only to find that there’s so m much wrong that I would have been better off getting another whole unit, hopefully a decent rebuilt unit that at least has a solid core.

 

@Beemon: Understood and agree on the crap shoot surrounding an old rebuild, but I have a kit from Jon that I could use if need be. I don’t mind doing the labor, but I want to start fresh (somewhat).

 

I just started considering getting a new Holley 2-bbl for about the same money as the Delco rebuilt unit. The Holley will require a manual or electric choke, an adapter plate, some accelerator linkage mods, and an aftermarket air cleaner, all of which I can live with for then sake of getting things to work right.

 

If anyone has any other suggestions after reading the additional information I provided, I'd appreciate hearing them.

 

jfd 

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Assuming the rebuilt Rochester is correct for your car, it will:

 

(A) fit, without the adapter, the linkage mods, the aftermarket air cleaner, and possibly transmission linkage mods AND a Holley guru to tune it!

(B) produce more power

(C) use less fuel

(D) be more reliable

(E) have better driveability

 

Jon.

Edited by carbking (see edit history)
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In further thinking about your carb . . . IF I was going to change it, I'd look more toward a reman unit from a '70 Buick 350 2bbl V-8.  I believe that one is probably the same 1.44" throttle bores as I suspect you carb is, PLUS it would have an external vacuum choke pull-off.  Metering might be a hair leaner with the later model, but not by a great amount, I suspect.  I've dealt with those internal choke pull-offs and have not had very good luck with them, for one reason or another.

 

There might be some issues adapting/cross-breeding the choke thermostat between the earlier and later models, possibly.

 

As for EFI, Holley just released a Sniper 2bbl FI unit.  It's purpose is to replace the Carter BBD 2bbls on Jeeps.  Jeeps which go into terrain rougher than I'd ever want to be in, but some want to drive in it.  The EFI is a bolt-on unit, to replace the "small" Carter BBD 2bbl, which I suspect is the same baseplate bolt pattern as your Rochester probably is.  Still past $1K by the time it's running on the engine, though.

 

I believe your intake manifold might have the "heat track" in front of the throttle bores?  That might need the correct metal gasket (as the 4bbl version does) to keep the exhaust from leaking around a more recent gasket.  Just mentioning this as a possibility.  I'm not sure, off hand, if it's there on your manifold or not.

 

Just some thoughts,

NTX5467

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Very seldom do I disagree with NTX5467, but in this case I must.

 

First, the internal choke pull offs virtually never give problems, and when they do the issue is easy to fix.

 

If an issue arises, it will virtually always be a result of the heat tube inside the manifold burning through, and raw exhaust flowing through the tube into the choke housing and causing either a burr or slight warpage in the cylinder housing the pull off piston. To repair:

 

(1) Remove the choke housing

(2) If possible remove the choke pull off piston

(3) Measure the O.D. of the expansion plug sealing the lower end of the piston cylinder

(4) Go to your flaps and acquire two (never hurts to have an extra), also a small sheet of 1200 grit emery cloth

(5) Drill a small hole in the center of the expansion plug in the housing, and pry it out

(6) Measure the I.D. of the cylinder

(7) Got to the hardware store and acquire a piece of dowel rod the next size smaller

(8) Get out your special carburetor rebuilding tool (a.k.a. hack saw) and cut a small groove lengthways in the dowel rod

(9) Carefully wrap a piece of the emery cloth around the rod, with the ends folded in the groove

(10) Using a variable speed drill, slowly ream the cylinder

(11) Clean the piston, re-install the piston, and check that it moves freely

(12) Once the piston moves freely, install a new expansion plug, and peen it into place

(13) MOST IMPORTANT -- FIX THE HEAT TUBE IN THE MANIFOLD!!!!!

 

Now, as to the later carbs with the external choke pull off. Personally, I have NEVER liked them, as the divorced choke has to compensate for the mass of the connecting rod, placing additional tension on the choke coil. Better than electric, but still inferior to the integral choke pull off.

 

HOWEVER

 

Today there is an additional problem. The divorced chokes and choke pull offs before about 1980 have been discontinued!!!!! We bought the complete inventory of P & D, as well as a lot of Hygrade, and a couple of other brands. Walker still has a decent selection, but choke pull offs in the era are disappearing, and divorced chokes have mostly disappeared. A very few are being reproduced off shore (NOS does NOT mean new off shore!) for big block Corvettes, RA GTO's etc.

 

As to electrics: I learned this lesson the hard way. Discovered the burned out exhaust tube on the wife's vehicle, and was busier than I should be, and installed the electric. Twice, it stalled with her at a stop sign 3 blocks from the house, would NOT restart as the choke was now wide open, and she had to walk. Removed the manifold, fixed the exhaust tube, re-installed the hot air choke, and the car performed normally........and she was happy! If you must use an electric with an older automatic transmission, start the vehicle, and go back in the house for a couple of cups of coffee. By the time you consume these, the engine should be at normal temperature and the electric choke won't hurt you. Or you could always upgrade to a manual transmission! ;)

 

Jon.

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Never had an issue with electric chokes. I understand everyone is privy to different circumstances and Jon is the carb king. However, a choke stove coil will stay open just like an electric coil after the engine is hot. When you turn the car off, both of them will be cooled the same due to ambient engine bay heat. I'm not sure the circumstances but seems a bit weird to me. The only difference would be how fast they heat up, where one is based purely on the exhaust manifold heat and will heat up with the car versus the other that heats up the same every time due to electrical heat. 

 

I have had issues with putting an electrical choke on a WCFB and having the vacuum piston leg bind on the backside of the choke, leaving it open. It's possibly the same issue. 

 

As always, though, I defer to Jon's wisdom. I just will always feign ignorance and use electric because I have never gotten a choke stove coil to work properly in 20 degree weather. 

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Ben - you hit on the issue - how quickly the different chokes open.

 

Older automatic transmissions can create more load on the engine. The older electric chokes (I have been told there are now adjustable ones available) would go completely off in 45 seconds to one and one half minutes. Since the choke is now off, the fast idle circuit is out of play and if one stops at a stop sign BEFORE the engine is warm, it will stall due to too slow an idle. Since the engine is still cold, it REQUIRES choke to keep it running when restarting. If one waits 15 minutes for the coil to cool, it will start; but many do not wish to wait.

 

Note in my previous post the reference to two cups of coffee? That gives the engine an opportunity to warm, as well as the transmission juices, and stalling does not occur. Once the engine is warm, there is no difference in the function of the electric or the hot air choke.

 

Personally, 2 of my 3 collector vehicles have been UPGRADED to manual chokes! :P And the one that came originally with a dogmatic transmission has been UPGRADED to a manual transmission! :)

 

But I believe keying the opening rate of the choke to the temperature of the engine is a good idea on older vehicles with automatics.

 

Jon

Edited by carbking (see edit history)
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Wow, this got complicated! First, I'm going to remain neutral in the Great Electric Choke War of 2018 ?. Second, my car doesn't have a heat tube because the choke thermostat is water-operated. I had the choke piston out last year and there wasn't any obvious crud on the piston or in the bore, and there was no binding as might result from a burr. Because there is no possibility of exhaust gases entering the choke housing, warpage of the bore seems unlikely, assuming that exhaust heat would be the only cause of a warped bore.

 

BTW, one of the reasons that I was considering picking up the Delco rebuilt carb is because it doesn't require a core return. That's of concern to me because of the makeshift accelerator link and the stripped screw hole I mentioned earlier. I don't think a rebuilder would accept the core as-is, and that would add quite a bit to the cost.

 

FYI, the carb I'm looking at is this one: https://www.ebay.com/itm/Buick-SPECIAL-SKYLARK-1964-300-8-cylinder-engine-DELCO-REMAN-CARBURETOR/382169976109?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649. In addition to the concerns associated with a rebuild that were already brought up, I've not been able to verify that it's the proper carb for my engine. I messaged the seller to ask if there was a printed part number on the box, or paperwork that verified the part number (the metal tag is missing, and pencil scribbles on the outside of the box don't do it for me). He said that the paperwork indicated a part number of 12-164, which I can't find a cross reference anywhere. Needless to say I don't have the warm fuzzies about this being the correct carb.

 

At the end of the day I might just install a manual choke and be done with it, not sure yet. Anyway, I appreciate all who took the time to weigh in and offer suggestions. As I normally do, I'll provide an update after I decide on a course of action.

 

Jim

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Jim - the carb in the link is correct for 1964 Buick 300 CID automatic transmission.

 

I would suggest disassembly and rebuilding with a currently produced rebuilding kit. It appears the original Rochester velumoid gaskets were used (observe corrosion beads around gasket surfaces). Velumoid had a high sulphur content. If the original gaskets were used, PROBABLY the original type accelerator pump was used, and the neopreme won't last 3 weeks in modern fuel. Since it has obviously been rebuilt (Delco did a great job for the fuel then use), you won't need one of our kits; just one of the cheap ones from your FLAPS.

 

Another one with a 60 day warranty is 272055405463 and it still has the original tag.

 

Jon.

Edited by carbking (see edit history)

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I'll admit that the few times I had any dealings with the internal-piston choke pull-off, it was in about 1968 as I was trying to help my Band Director get his '52 Chevy to run better.  The whole linkage stuff looked flimsy to me.  But, as Jon mentioned, there were probably other things involved that I had no knowledge of, in getting the vacuum to the piston to make it all work as designed.  To me, the external pull-offs were a much better arrangement.

 

From what I've seen on the automatic chokes on the care I own, few were calibrated (to factory specs) in a manner that resulted in their best performance, for how I drive AND our climate.  I usually ended up re-bending the external links to the choke linkage, re-setting the fast idle speed screw, and (usually) leaning out the choke thermostat setting (a notch or two).  End result was that even in 30 degree F weather, the engine was at close to "base idle" in about two miles of driving.  No need to let it run, just drive it easy once it starts and runs.

 

ONE part of this strategy was the NGK V-Power plugs I came to use.  That particular electrode design puts the spark out to the edge of the ground electrode, for more exposure to the air/fuel mix.  Once my Camaro would fire off, cold, I'd put it in reverse to back out of the driveway.  If is acted like it would falter, a short at on the accel pedal to get a quick pump shot from the OEM-spec 9895 Holley 4175 was all it would take to keep it running.  By the time I got to the 2nd stop sign from the house, it usually was on base idle, running reliably.  Without a "snorkel" air cleaner.

 

When the Camaro was new, it had the stock 2bbl on it.  Sometimes, it wouldn't come off of the top fast idle notch, even with the windows steaming from the defroster.  I'd have to put it in gear and turn the ignition off.  THEN it would release.  Never did figure that one out.  On those middle-70s years, the carb choke got its heat assist from a tube which was in the center heat crossover passage in the intake manifold.  A neat and easy to access system!  But it also required a piece of special high-heat silicone vacuum line to get the heat from the crossover tube into the choke coil area.  Normal hose would melt!

 

When I upgraded to a 4bbl intake with an electric choke, I got the Holley Thermister.  It was supposed to vary the amount of juice to the electric choke by engine temp.  Didn't work for some reason.  I spliced into the brown wire from the alternator, which later entered into the harness "+" system.  Tried to run it via a 3-prong oil pressure switch, but that didn't work, either.  So I just used a normal hot lead, of sorts.  Then tweaked it until it worked like I wanted it to.

 

To me, the Rochester 2bbl is one of the most bullet-proof carbs ever produced -- period.  It just works and stays working for a long time.  There were some emission tweaks in the '70s models, in some cases, and also several 1.69" throttle bore versions, too.  One of the best stock-running Chevy 350s I drove (a friend's '70 ElCamino) had that larger version on it.  For many people, it runs as good as a QJet 4bbl 350, on a stock engine.  Be that as it may. 

 

And then there were the 1.44" throttle bore models that were on many Buick small V-8s.  Very good off-idle throttle response, being basically the same size as the primary side of a QJet.  So for most drivers, runs at least as good as QJet 4bbl, but without the "top end rush" power.  

 

To be sure, a normal Buick 350 QJet engine will run and feel better than a similar small block Chevy 4bbl, by observation.

 

As I've progressed in age, as have the cars I own, the number of service techs that know what they're looking at has decreased.  This is one reason I made that "later model carb" suggestion I did.  Plus what I consider a more modern way of doing things with the automatic chokes.  Thanks for the updates on the choke pull-offs, too, Jon!  Another reason I tend to gravitate toward recent-production carbs rather than used, OEM-spec carbs of questionable internal condition.  Just my preference, for what it's worth.

 

I commend Ben on his progress with his EFI system on his Straight 8 Buick.  As I recall, it's increased both highway fuel economy plus basic drivability, which it should, in theory.  The newer self-learning EFIs, too, require a compatible distributor input, typically, in addition to just the EFI kit itself.  I do feel that they can improve many operational parameters, BUT much of their improvement can also relate to how "out of whack" the factory calibration might have been in the first place.  Especially if a more efficient intake manifold compliments the installation.  In the mean time, I'll stick with the carbs I know how to work on.

 

As time progresses, too, there will be more self-learning EFI kits for more engines.  The recent Holley Sniper kit for a Carter BBD 2bbl Jeep application is one such item.  With good fuel tank baffling, the EFI will allow the vehicle to get into even MORE challenging terrain, I suspect.  But it can also be added to other small V-8s where the small BBD was used, possibly with some fuel curve tweaking for the 5.2L V-8s.  AND, the price will decrease as time goes on, too!  But with new Holley 4175s now being near $500.00, in comparison, that $1000.00+ price of a self-learning EFI becomes more reasonable, for many.

 

What Ben used is an OEM-based TBI system, with a "custom chip" for his application.  Similar in concept to the many ScareBird item upgrades, but for EFI and instructions, from a different place.

 

Just some thoughts,

NTX5467

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Thanks for the kind words, Willis, but what is this " I'll stick with carbs I know how to work on" you speak of?:D   Why do you have to work on them?  The only time I have had to do ANYTHING is when I pinched an injector HOT wire between the air cleaner and throttle body.

  Seriously, nothing wrong with the carbs.  Gas , ethanol notwithstanding, today is formulated differently. I think. That's my story and I am sticking with it.

 

  Ben

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"Know how to work on", from prior experiences.  Once done, no issues for 100K+ miles, typically.  Even on the Holley 4bbls.  "Your experiences might vary".

 

NTX5467

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Jon: I decided to buy the other carburetor that you pointed out to me. I chose that one over the Delco rebuilt unit mainly because it's a newer rebuild, and so it's less likely that I'll have to do anything to it like replace old gaskets or the accelerator pump. It also comes with a 60-day warranty, for whatever that might be worth. I think that one is a lower risk overall, and the seller accepted a lower offer. Thank you and Beemon for the thoughts on the older gaskets, something that I hadn't considered.

 

Regarding EFI, I have mixed feelings about it. It's a very attractive option, but for me part of the pleasure of having and driving an older car is reliving the full experience, annoyances and all. I would certainly think differently if it was my daily driver.

 

Jim

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5 hours ago, Machine Gun said:

the pleasure of having and driving an older car is reliving the full experience, annoyances and all. I would certainly think differently if it was my daily driver.

 

This is why I've kept my car mostly stock, but it is trying at times... especially for a daily driver lol. Good luck with the carburetor, let us know what happens!

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6 hours ago, Machine Gun said:

 

 

 , but for me part of the pleasure of having and driving an older car is reliving the full experience, annoyances and all. 

Jim

 

 Well said sir.  My sentiments as well concerning my Buicks.  Good luck with your purchase!  

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The carb arrived on Friday, and I installed it yesterday morning. It performs perfectly. The vacuum-operated choke release works as it should, and the car accelerates from a dead stop and also while at speed without stumbling, two issues that I had unsuccessfully battled with over the four years I've owned the car. The only issue that came up is that the thermostatic coil assembly that the coolant runs through leaks inside the choke housing. I contacted the seller to request a repair or replacement of the part. I swapped it out with the one from my old carb for the time being so that I can keep the car on the road this weekend. So there you have it.

 

Jim

Edited by Machine Gun
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