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| | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | | | | | | Joined: Sep 2008 Posts: 872 Shop Shark | | Shop Shark Joined: Sep 2008 Posts: 872 | Nothing super obvious. Are you having a problem? | | | | | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | They look like wide gap. Are you using HEI?
See the USA in your vintage Chevrolet! My Blog | | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | Im running HEi so I have a larger gap. think its .06 odd. Cant remember off the top of my head but i can always verify of check my record sheet when i get home.
Just wondering if some others might think its lean. Nothing i can really do anyways as the jets for the carbs I have are impossible to get.
I have been fiddeling with the truck since last fall after getting my second set of new carbs but the truck still has no real get up and go. Granted its better than last summer but still seems lacking. Im at my wits end with trying to tune it. | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | My first impression was it is running lean. What kind of carbs are they?
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | The ever so famous Tom L progressive 2 barrels that i dove into rather than planning it out correctly. | | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | Talked to Tom last year about possible new jets and he seemed awfully offended that i asking about changing the jetting. He said the stock jetting setup is always perfect. | | | | | Joined: Oct 2006 Posts: 843 Shop Shark | | Shop Shark Joined: Oct 2006 Posts: 843 | I agree that they are lean. Ideally the porcelain should be a tan colour.Try 45 for gap on the plugs. | | | | | Joined: Jan 2014 Posts: 3,690 'Bolter | | 'Bolter Joined: Jan 2014 Posts: 3,690 | Talked to Tom last year about possible new jets and he seemed awfully offended that i asking about changing the jetting. He said the stock jetting setup is always perfect. Complete shot in the dark: Does Langdon know what kind of manifold you're running? There are a number of folks here who seem to run that setup very successfully, but I'm guessing vast majority are using one of the more commonly available Offy or Fenton intakes. Looks like you have something a bit unique. Is it an Edmunds? Perhaps the various two carb manifolds have different flow characteristics?
1951 3100
| | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | Im using a Edelbrock intake. Have talked to tom lots of times over the last few years. He Knows of my intake and full setup. The full system setup other than the intake was purchased thru him. | | | | | Joined: Feb 2004 Posts: 29,881 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,881 | Try blocking the choke plates partway closed. If the performance increases and the plugs go tan or at least not pure white, you're definitely lean. Carburetor jets and number drills go together nicely, but you can't "un-drill" one if you get it too rich.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | I agree that they are lean. Ideally the porcelain should be a tan colour.Try 45 for gap on the plugs. Checked the current plug gaps and my paperwork from Tom and they are to be set to .065. Changed them down to .55 yesterday and now the truck has zero power. Takes forever to get going. | | | | | Joined: Oct 2006 Posts: 843 Shop Shark | | Shop Shark Joined: Oct 2006 Posts: 843 | I was gong by a GM book I have for the gap. I did see that early GM HEI used a .065 gap. Sorry for the mis-information. | | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | no worries i was interested to see the results anyways. | | | | | Joined: Sep 2008 Posts: 872 Shop Shark | | Shop Shark Joined: Sep 2008 Posts: 872 | If the mix was to lean wouldn't the base ring also be 'clean'? Seeing that all 6 plugs show some carbon on the base ring tells me that the mix is *maybe* at the upper end of of proper range.
The heat zone on the center electrode also looks to hot (not mixture wise, but heat zone wise).
Maybe go down in heat range on the plugs?
Does the motor ping under load?
The original AC-44-5 plugs were mid heat range... like a 4 or 5 on a scale of 1-10.
The rj18yc6 seems to be a hotter plug rated 6-7 on the 1-10 scale. Maybe try rj12's or rj14s and see what looks (and runs) better.
Last edited by pfarber; 04/24/2015 9:56 PM.
| | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | i will give the 14s a try this weekend and let you guys know how it turns out
| | | | | Joined: Oct 2006 Posts: 1,847 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 1,847 | I have spoken to Tom as well, although my issue was a little different. But in any case I was trying to get larger jets too. He said it was most likely some crud stuck somewhere, and to take them all apart and clean them. As you have mentioned he seemed somewhat aghast that anyone might need to actually tune an intake system. But I have read several articles/posts about/by people who changed the jet sizes in this application, by either drilling them out, or getting new ones, (at least one of the people was successful in locating different jets, and no I don't remember, or I would be getting some for myself.) So I don't suppose it is completely out of line to figure you might need to do a bit of "ADJUSTING", I mean you need to tweak pretty much anything you buy anymore, don't know why this should be any different. | | | | | Joined: Mar 2010 Posts: 10,310 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,310 | I would guess that Tom's reservations on recommending re-jetting are based more on people's knee jerk response to do that before trouble shooting everything else, rather than arrogance.
It is synonymous with when we have a rough running, factory stock engine and make the mistake of jumping into the carburetor before looking at EVERYTHING else first.
Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Sep 2008 Posts: 872 Shop Shark | | Shop Shark Joined: Sep 2008 Posts: 872 | The second set of plugs look similar to the first and I really don't see a huge issue. What are people seeing that makes them say the mix is lean??? HERE IS A CHART that shows lots of plugs and to be honest yours look like the 3rd row from the top first or second from the right... marked 'Good'. Can someone clarify what I might not bee seeing?? | | | | | Joined: Feb 2004 Posts: 29,881 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,881 | That chart is about as up to date as a T-Rex. I haven't seen plugs with those colors or those type of deposits since they quit putting lead in gasoline.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2014 Posts: 385 Shop Shark | | Shop Shark Joined: Sep 2014 Posts: 385 | The second set of plugs look similar to the first and I really don't see a huge issue. What are people seeing that makes them say the mix is lean??? HERE IS A CHART that shows lots of plugs and to be honest yours look like the 3rd row from the top first or second from the right... marked 'Good'. Can someone clarify what I might not bee seeing?? The info I see on the web seems to indicate to me my first set in question was possibly a bit lean. This second set in on now looks completely different to be vs the first set. Truck now seems to run the same now with the 14's as it did with the first set of 18's. I'm guessing I'm better to keep running the cooler ones anyways. I will recheck them in a few hundred miles when I fill up. Next issue to move onto us the fuel smell that I get swamped with as I accelerate aggressive. | | |
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