Edelbrock carb question (Gary, Bill or anyone)

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Edelbrock carb question (Gary, Bill or anyone)

Whisler
I have a #1806 Edelbrock carb on my 351W engine and I believe it is running somewhat rich. I read over the Edelbrock tuning manual and it gives very good info on setting the Cruise mode but only says to be careful not to set the Power mode too lean with no test method. How do you test for proper Power mode setting?
Any advice appreciated.
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Edelbrock carb question (Gary, Bill or anyone)

Gary Lewis
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The snippet below from that manual is what we need to discuss.  And in it the cruise mode is on the vertical scale and the power mode on the horizontal scale.

Assuming stock metering you should be at "1".  And to keep the power metering the same while leaning the cruise you could go to "19", but that leans it two stages or 8%, which is a lot.  Or you could go to "16", which will lean the cruise by 1 stage or 4%, although it will also lean the power mode by 2%.

And now to the question - it is hard to test the power mode quantitatively w/o an AFR meter.  But typically these carbs are tuned pretty rich in the power mode so leaning it a bit won't hurt, and 2% qualifies as "a bit". And if the engine still runs strong when you are "into it" you are fine.


Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: Edelbrock carb question (Gary, Bill or anyone)

Rusty_S85
In reply to this post by Whisler
Whisler wrote
I have a #1806 Edelbrock carb on my 351W engine and I believe it is running somewhat rich. I read over the Edelbrock tuning manual and it gives very good info on setting the Cruise mode but only says to be careful not to set the Power mode too lean with no test method. How do you test for proper Power mode setting?
Any advice appreciated.
Couple ways you can test your power mode.

First way is to install a O2 sensor in the exhaust pipe and read what your A/F ratio is when you nail the throttle and do heavy acceleration.  It should be rich preferably around 12.5:1 for max power/torque.

Second way is to listen for detonation when you nail the throttle listen for pinging under heavy load.  A lean fuel mixture will detonate while a rich fuel mixture will not.
"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2
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Re: Edelbrock carb question (Gary, Bill or anyone)

Whisler
Thanks guys.
Gary I was looking at the same chart but was unsure if I needed 19 or 16 setting and how much was "a lot" and how much was "a bit", as you put it. I'm not sure if the jetting has been changed in this carb as it is a used carb and came from an SS 396 Chevelle. I will check the jetting that is in it now and see what I have. 19 seemed like quite a change for cruise mode and 16 seemed more reasonable for cruise mode but not much change in power mode. but then I didn't know what 2%, 4%, or 8% amounted to in these carbs. I guess I will order a jetting kit for 1806 so I have the options I need unless you all think that is wasting money.
Any and all comments welcome. I need the education.
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Edelbrock carb question (Gary, Bill or anyone)

Gary Lewis
Administrator
If you think it is a bit rich then ordering a jet kit is the thing to do.  It will let you dial it in to your needs.

But back to the different "modes" of operation:

Cruise: This is when the vacuum is above the point where the metering rods come up, and that is determined by the spring under the piston.  And the air/fuel ratio is determined by the diameter of the primary main jet and the diameter of the cruise part of the metering rod - the larger diameter.  You want this to be lean enough to get good economy but not so lean that the engine falls on its face when the vacuum gets down near the pop-up point.  You can enrichen the mix slightly if it does that by going to a smaller rod or larger main jet, or increase the spring strength so the pistons pop up a bit earlier.  But be aware that changing the jet or rod may also change the AFR in Power.

Power: This is after the vacuum drops below the pop-up point but before WOT.  And the AFR is determined by the primary main jet and the tip diameter of the rod.  This AFR needs to be richer than Cruise so the engine picks up a bit of power to climb a hill or accelerate briskly.

WOT: This is when the secondaries come in, and that is determined by the amount of air pressing against the air valve and the tension on the spring that is preventing the air valve from opening.  The air trying to come in is due to RPM, and in the AVS that spring tension is easily adjustable.  But the AFR is not if I remember correctly as the secondary jets are not replaceable.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: Edelbrock carb question (Gary, Bill or anyone)

Whisler
Gary: Thanks for the thorough explanation. I will definitely buy the kit, because I am not sure the current jetting is stock. That will at least let me try stock jetting if it currently isn't.
Thanks and God bless.
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Edelbrock carb question (Gary, Bill or anyone)

Whisler
I went to Edelbrock to buy the carb. re-jet kit and they were out of stock. Summit has the kit but several of the reviews said that they received their kit minus the #1416 rod, just what I need to get to position 16 on the chart. Just my luck! Guess I will wait for Edelbrock to re-stock.
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Edelbrock carb question (Gary, Bill or anyone)

Gary Lewis
Administrator
Hang in there, surely Edelbrock will get them in stock soon.  
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: Edelbrock carb question (Gary, Bill or anyone)

Whisler
Update: Finally got my Edelbrock Carb re-jet kit and dived into the carb. Removing the rods I found them to be the stock rods (.068x.047). When I checked the jets I found them to be .098. This rod/jet combo (#11) gives the richest cruise setting on the the chart and the second richest power setting. No wonder it seemed rich and got lousy mileage!

I switched rod/jet combo to #16, 1 stage lean in cruise and 1/2 stage lean in power. Seems to run fine like that but later on I may try #19, 2 stages lean in cruise.
Thanks for the advice.
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Edelbrock carb question (Gary, Bill or anyone)

Gary Lewis
Administrator
Well done!  That’s the way to do it - trial and error.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI