Cliff's Quadrajet Parts and Rebuild Kits
Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: dlong70elcamino on June 06, 2016, 08:44:46 PM
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Boy i,m really fighting with this Q jet i built for my Elcamino it acts like it running out of fuel at the drag strip above 5000 rpm I usually shift at 6500. It launches great but bogs out at high rpm like someone shut off the fuel. Gonna try a 110 gph mechanical fuel pump next.It,s weird it didn,t do this with the 600 Holley that was on it but it had two fuel bowls and this one has only one acts like bowl is sucking dry if i let off it will come back but when i push it open again same thing. Bummed :( It had 6-7 psi with old pump don,t know what it is at high rpm.
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I've seen people have success with this problem by removing the small inlet fuel filter and installing a larger in-line filter between tank and carb. If that doesn't help, remove the nylon sock in the tank. Those can get clogged with rust, sediment, etc.
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What is your quadrajet number?
What is your float height set at?
Did you use Cliff's High flow needle/seat?
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It,s a 17057213 carb all parts came from Cliffs 135 needle and seat float was set to spec for that carb don,t remember the setting but its not low most Q jets the float should look level in the carb when set right.
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Measure the float. set to 9/32"
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Pretty sure its set at 1/4" that is what Cliffs book says and that is what he told me to set it at. So 9/32 is actually lower so why do you think that will work do you think its flooding out cause normal street driving its fine as long as the 4bbl is not open a long time.
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You said the float was set to spec for carb. You didnt indicate you set it by Cliff's recommendation. If it is truly set to 1/4 then that is fine.
I am just trying to help.
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Boy I hope you didn't think I was ungrateful carmantx im glad you chimed in that is how stuff gets fixed is when someone knows more than you which there always is or they have had that problem and know the fix. I appreciate your help buddy I worked as a GM mechanic for 28plus years and you got to use ALL your resources to fix stuff. I replaced the pump yesterday ill take it to the track today and keep ya updated Thanks ....Dan
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How much power does the engine make and how quick does the car run?.....Cliff
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Cliff not sure of the power output.but i think i finally got it to not run out of fuel with a new 110 gph mechancal pump I got from summit.I had to Norwalk last night and it ran a best of 14.30 at 93.41mph I was hoping to get into the 13s several years ago it ran a 14.55 with 2.56 gears and a 600 Holley no other changes.It dont seem to want to pull hard over 5500 rpm. It does come out of the hole like a beast now with the Q jet 60 ft is 2.011 I know its a heavy car have not had it weighed but most of what i read about 3800lbs no driver. Maybe its too much carb? engine specs- 350 stock bore 10.0 to 10.4 cr 202 1.6 heads 165 runners Torker 2 intake 17057212 Q jet cam is 520 lift 292 dur 114 LSA
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You aren't making enough power or running quick enough to be having fuel delivery issues with a .135" fuel inlet seat in that carb. Not sure what's going on, but for sure I would check everything before the fuel pump to see if there is a restriction someplace.
Some fuel tanks uncover the pick-up quite easily at the track as most are front located and the back part of the tank has a long slope to it.
The T-II intake isn't helping things much, unless you have a lot of gear/converter the carb woln't leave hard and take while to get into the good power. The T-II is also set up with a square flange and requires an adapter from what I can remember, another potential "choke" point in the system.......Cliff
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Cliff I got the running out of fuel problem fixed with the new pump I even had the fuel tank down to 1/4 tank or less and it was ok. I just think the engine should make better power at higher rpm I am wonder if its too fat on the secondary side I am going to take some secondary metering rods to the track next time and lean it back some to see what it does. I got some AY,CP,DP, and its got CEs in it now.
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I agree, with 292 duration on a 114LSA it should pull really hard past 5000rpm's, that's a LOT of cam for 350cid at 10 to 1 compression. I only run 289/308, 236/245@ .050" cam in my 455 at 11 to 1 compression and it makes great top end power and still pulling really hard at 6000rpms.....Cliff
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Update:well Cliff I had it to the strip this week end and it ran great. Man I was about to give up on this Q-jet. Here is what i did took out the carb filter replaced with a in line filter and took out the choke plate and added 4 degrees to the base timing now the base is at 14 degrees didn't check it at all in advance but the engine loved it. Got the car weighed its at 3760 with me and 1/4 tank of fuel. It ran a best time of 13.66@ 97.98 mph 60 ft was 1.9 on all 6 passes and mph was 97 on all 6 too boy i was pumped 14.30 was the best it was running I,m shifting @5500rpm ran it clear down to 1/8 tank of fuel no problems. Thanks for your help. Dan........ :)
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Good news! Nice runs, but I think there is more in it, should be running over 100 mph for that ET, keep tuning......Cliff
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Update: Cliff its getting better got timing set at 14 base 38 total ran it yesterday got a 13.58@100.24 mph its getting there its spinning like crazy on street tires have to launch soft might have to get some slicks next. Q JET POWER loving it.If anyone says you cant run fast with a Q JET they don,t know what they are talking about. Thanks again Cliff.....Dan
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Good news. Everything changes with slicks, typically ET picks up quite a bit at about the same MPH, keep us updated on the results.....tks....Cliff
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Update: Cliff had her at Norwalk last week on Wed ran best of 13.30@ 100.18 mph new record on street tires and headers uncapped won 3rounds of eliminations. One happy camper here. It may have more in it i will keep tinkering. Qjet POWER .......Dan
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Last update for the season Cliff had it at Norwalk on 10-12-16 ran the best of all season got 74 passes on the car this season a lot of round wins and a best run of 13.24@ 102.25 mph 3760 lb car with a 350 ci Chevy on 93 fuel and a 750 Q-jet not too bad.Thanks again for all your help and good parts Cliff.......Dan
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Good news. We've been blessed with warm weather this month. I think that's all about to change. When do they shut down for the year?......Cliff
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Cliff that was their last Wed and the Halloween Classic was last weekend. I think I'm gonna run the Camino down at pacemakers on the 28th and that will be it for this year. I think I'm gonna pull the motor this winter and look it over and do some head work. I built it 12 yrs ago and haven't even pulled a rocker cover since lol.
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I didn't make it to Pacemakers this season, or anywhere else. Need to pull the engine in the Ventura for a freshen-up first.....Cliff