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#1
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'62 4cyl Rochester 4gc
I've got a little dilemma here...after patiently (which I'm usually not lol) waiting 2 years to find a stock Rochester 4gc for my '62 Tempest with the 195, there's a part missing from it and it's the only Rochester model that I've seen with it...the fitting located between the 2 mixture screws on the throttle body. The one I got has a hole in this location about a 1/4" wide and looks like there's a shiney piece of metal lodged deep in it...don't know what it is and what it's for. The 1962 Tempest Shop Chassis Manual doesn't say or point out what it is. From pix that I've seen, it looks like a fuel line screws into the fitting but the hole in the throttle body isn't threaded, so it must be a tight fit. Can I find a part like this anywhere or have a machine shop make one? Or even find a throttle body for this carb (7020066)? Thanks
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#2
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Post a picture
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#3
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DeeRock, Sorry I haven't got back to you before now. I just looked at my 4GC, and It does not have what you are describing. Not surprising though, because my carb that came on my 4bbl intake had no tag or any identification anywhere on it. I ordered a kit from Carb King, but it was all wrong. I had to go to my local wrecking yard and buy another carb with a tag and then built it. Neither of which came on a 4 cyl. Tempest. If your carb is original, can you tell me what jets are in it? The jets I got from Carb King were 46's. The ones in the other 2 carbs are 57/67 and 58/69. Probably WAY to much jetting for the 4 cyl. even with being +.030, more cam, header etc.
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#4
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__________________
My Pontiac is a '57 GMC with its original 347" Pontiac V8 and dual-range Hydra-Matic. |
#5
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A picture of the throttle body, Ace. Give people a clear idea of what he's talking about.
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#6
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When I get home, I'll post a pic of the carb throttle body I got and then post a pic of 2 others, one of which is from the shop manual, to make a comparison. My apologies for the delay.
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#7
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This is from the shop manual...it's that cylindrical part between those 2 idle mixture screws. For the pic below, here's a shot of some guy's Rochester 4gc setup in his '62 Tempest...that "problem" part has a line hooked up here and I don't where the other end hooks up to. Last edited by DeeRock Lemans; 07-02-2013 at 12:38 AM. |
#8
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Here's mine...in these shots, it looks like it's in a lot rougher shape than it really is but it's just really dirty, after sitting outside on an 87z code engine for who knows how long. But notice the hole where that fitting is supposed to be? This is actually an old shot (my camera is charging up right now), but in the hole there, I cleaned it out a little and there's a shiny piece of metal in it, thought it was a screw at first but looks little damaged. Will take a shot of it later. Last edited by DeeRock Lemans; 07-02-2013 at 12:36 AM. |
#9
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Here's a shot from the underside...in that small hole between the 2 smaller jet holes, there's a small corkscrew-looking piece of metal in there and have know what it is, what it's for, or if it's even supposed to be in there...maybe it's a part of that metal piece in the hole. Haven't taken it apart yet, so maybe some answers will be revealed then. This is one strange carburetor! |
#10
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missing part
Looks like a vacuum port to me. There should be a fitting screwed into the carb base that connects that port to a line that supplies vacuum to the automatic transmission vacuum modulator.
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#11
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Yep, manifold vacuum. If not blocked, carb cleaner in the hole would come out the bottom port between the primaries.
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#12
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Thanks fellas, looks like we're starting to get somewhere now. A vacuum port...wow. So in order to make this carb to work, I'd have to have that part in the vacuum port removed (something I'd have a professional do, like maybe Carb Doctor), have the hole threaded, and then have a machine shop make a fitting? Might cost a little $, but, if that's what needs to be done....
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#13
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If you don't plan on using it then chase some threads into it and plug it. Nothing to it. Bet Keith can set you up. Didn't he help you with some other stuff?
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#14
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carb pictures
Agree with banshee, if you are running a stick, thread the hole with a pipe thread tap and plug it. If you are running an automatic, find a fitting from another car and thread it in....or the one barrel 4 cylinder motors I have take manifold vacuum from a fitting on the intake. You could do the same with your 4 barrel intake and leave the carb plugged.
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#15
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OK..mine's an auto, the stock 2-speed.
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#16
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Derek,, If you have a caliper, measure the hole & let me know what size it is. I have pipe taps. Should be no problem. The stock 1 bbl setup draws vacume off of a fitting behind the carb. Just leave that as is & we can plug the hole in the carb. Are you rebuilding it yourself?? or taking it some where? Either way, it needs to be tapped out before its rebuilt.
__________________
Keith Collier 61-63 Pontiac Tempest Tech advisor POCI.org |
#17
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OK...so being that mine is an automatic, it sounds like it needs the fitting on it, clearing that piece of metal (maybe it was put there as a plug) out of that hole? Sounds like if it were a stick shift, then it would need to be plugged? And yes, Banshee, Keith helped me put the motor mounts in a few weeks ago, made a huge difference! Great guy to meet and we spent 2 hours talking Tempests afterward. But yes, I'm planning on rebuilding it myself, just like last year, when I rebuilt the 1bbl carb myself, for the first time. Never messed with carbs or even understood how they worked before that and while it was a little tricky at first, it got done and she drove and ran a million times better after that. But of course, the 4bbl is bit more complex...when I put it in, I might feel safer having Keith work with me on that. The manual has a whole section covering how to adjust the 4bbl, but looks like it maybe a 2-man job.
One more thing, that sucker needs to be cleeeeeaned, so before reassembling, would it be a good idea to dip the parts in that carb cleaning solvent that comes with a metal basket? Last edited by DeeRock Lemans; 07-02-2013 at 08:45 PM. |
#18
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Poncho-V,
It's all good, sounds like you had a lil carb dilemma there, too. I don't know what kind of carbs you got, but from what I've read about Rochesters, sometimes, they have the model number stamped on carb body somewhere, but I don't think they all do. I'm just barely learning about these 4gc's, mine came with a tag. But the 7020066 is the only model I've seen come with that fitting, no other 4gc's that I've seen have that. As for jets...can't tell you, at least until I get the rebuild kit and then I might be able to find out. Is your Temp a stickshift? Have you tried asking the guys at Carb Shop in MO? Another place that might help you is Chicago Carburetor...I've never done business with them, but they might be worth a try. |
#19
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Yeah, DeeRock, it's been an ordeal. I have talked to just about all the carb places I can find. Mine doesn't have the number stamped on it. From looking back on pics I took before disassembly, it looks to me as if my trans vacuum line would have gone to the port you are describing. You can see mine went to a port on the front passenger side. If you could, I would be very interested in knowing what jets are in yours from the factory. That would at least give me a good starting point.
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