Cliff's Quadrajet Parts and Rebuild Kits
Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: kilowattkid on September 17, 2017, 06:39:10 AM
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Greetings,
I just wanted to put this out there on what I'm working with and Cliff is helping me with. He'll be giving me a baseline to work with hopefully this week. Anyways, here's my combo and carb info-
Cliff,
Here is the total recap of our emails and info on car / carb.
carb ID - 7044513
ordered HP kit, tubes and power valve springs - invoice ID#169
motor specs - SBC 385, 10.5:1 CR, scat crank and rods, full floater flat top pistons
Cranking compression - 1-165, 2-185, 3-170, 4-180, 5-165, 6-165, 7-180, 8-170
cam hydraulic roller 242 duration at .050, .585 lift with Harland Sharp 1.6:1 roller rockers - cam card attached
heads - dart iron eagle , 180 runners, 64cc chamber, 2.02 int, 1.60 exh
intake - edelbrock performer
exh - hooker super comps
car - 74 Nova full interior
trans - TH350 w/ 28-3200 TCI 10"
gear 3.42 posi
carb info -
idle tube - .040
idle channel restriction - .055
upper idle air bleed - .085 (this is the one that had the rivet in it, I'd like to plug it and make upper idle air bleed in air horn) picture attached
lower idle air bleed - .055
mixture screw hole - .067
idle bypass - .098
idle bypass restrictor - .028 picture attached
primary throttle plates - 5/16" hole drilled in them
pri rods - 36b
pri jets - 71
sec hanger - J
sec rods - AX
Let me know if you need any other info and let me know what else I may need (jets and rods)
Thanks for all the help,
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I'm going to give a recap of my 60+ emails between Cliff and I in regards to this carb. It's been a process, but we got it. All these posts will be by me, but I''ll distinguish what me and what's Cliff.
First and foremost, he told me I will need jets, needles, Piston springs and more idle air and fuel.
I then gove him all the info in my first post in regards to cam and engine combo. He let me know I'd need some more timing and lots of air. My cam is the biggest problem. Sounds good, but not real friendly.
We determined that the base line was way off, and created baseline.
I sent him pics of the throttle plates for a baseline, and now he'd seen I was fully on the main system.
I also gave him cranking compression readings due to the cam overlap really wanting a little more compression.
We also seen a few mods that were not right. Those are shown in some other pics in my last post.
more to come in another post
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more info to cliff
Any ways, in regards to that plug in the upper idle air bleeds, instead of tapping, plugging and drilling, can we plug it and put upper idle air in the air horn?
I also have a 7044224 body I could use.
Okay, here's my measurements-
Idle tube top- .052
Idle tube bottom - .040
Down channel restriction - .055
Upper idle air bleeds (had plugs in it) - .086
Mixture needle opening - .067
Idle bypass (bottom of baseplate)-.098
Idle bypass (top of baseplate, restrictor in place) .028 (picture included)
Pri rods -36b
Pri jets -71
Sec hanger- j
Sec rods- ax
Sec main well bleed tubes, top -.046
Sec main well bleed tubes bottom -.025
Sec accelerating tubes bottom -.073
Sec accelerating tube hole in air horn -.052
I think that's all of them, if not, let me know.
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Forgot to add that the primary throttle plates have a 5/16" hole in them.
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I'll post more later, but bottom line, we made wholesale changes to timing and air / fuel mixtures. Petroleum Picasso he is. LOL
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Bottom line though, I s my stuff was so far out of wack, but cliff worked me until we got it right. I.m amazed at what we did to make it work. like I said, more to come.
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Good news, glad to see that it's coming around well for you and you can enjoy the car a few more weeks before the bad weather sets in here.
It's interesting that just a few days ago I got blasted in public Forum by a new member for wanting details on the engine combination that they wanted help with. He went on to tell the readers how simple this stuff was and that there was no need for detailed engine specifics to get a good starting point on one of these carburetors.
I think you'd agree at this point that nothing could be further from the truth!
Anyhow, glad to see it's coming around well and I'd love to see some track numbers on the car if you get a chance to race it.......Cliff
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I would agree that engine specs are critical to setting one of these up. Unfortunately that member will be the guy to continue to call them "quadra-junks" when he can't get it set right.
Adding to my other posts, We ended up with the following-
blocking the upper idle air bleeds with a 4-40 set screw (loc tite of course) and drilled the air horn at .040"
put the new idle tubes at .036" instead of the.040" that they were
removing the welch plug and APT to add the external on in the kit
set the bypass air to .110"
put .046" drive in restrictor in the main air bleed in the body and air horn
70 jets and 46 rods
Fired it up and noticed quite a bit of improvement, but still too much throttle angle. after many more e-mails and stories we ended up with this to add-
moved vac advance to ported source
added base timing to 14 degrees and took bypass air to .140"
at this point we were real close, but not quite were I wanted it. I kind of thought though that I was running out of room.
Ended up going to .160" on bypass with no change, but on a whim and without advice from Cliff, I went to .180" on my bypass air, making sure that was the size through all the channels and it seemed happy and I was able to go to 16 degrees base and 34 mech advance and I had a very happy motor.
I have used q-jets on this car for 30 years and I thought I knew a lot about them. My motor has always been a 355 and now it's a 385 and I have never had an engine with this much cam and overlap, which was the biggest issue to overcome. I have definitely learned a whole lot more through this process and in reading the book.
I'd like to share the whole process, but with over 70 e-mails of info and stories, I don't know if that's possible.
Think about that for a minute, over 70 emails! That my friends is what customer service is all about.
Cliff, I can't thank you enough and please feel free to share with the forum any other info I may have missed. It was a pleasure in dealing with you on this.
Jerry Harter
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Thanks for the kind words Jerry and I'm glad that you got the carb where it needed to be and the engine performing like it should.
I don't mind putting the time in with these sort of things as a good end result is on our list of priorities for our customers. We took a slightly different direction with your carb that I do with most of the ones we set up.
Your engine combination for sure was more challenging simply because of the size of the cam (duration) and tight LSA in comparison to the CID and true static compression ratio.
It does however show us that even a later model emission calibrated Q-jet can be made to work fine far outside of it's original application......nice work!......Cliff
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Well, my neighbors may have thought I was just starting it, stopping it, starting again, high idle, rev it up and generally making noise.
In actuality, it is amazing to listen to the progression and go from gurgling pig rich with high throttle angle and lots of nozzle drip to a clean idle and a crisp throttle response. Certainly adds another element of knowing your car inside and out.
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That's one reason we bought property WAY out in the country back in 2003 and built our shop out here. There isn't anyone close enough to us so that we're bothering anyone running loud engines and such.
Back when I lived in Pittsburgh Pa there wasn't a week went by someone didn't call the Moon Twp Police and have them pay me a visit for doing exactly what you were doing!.....Cliff
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@Cliff Ruggles
Long time , no type!
Wanted to bring you into the new chapter on this car and possibly a little direction from you.
I just got the car home from the body shop with new skin on it. While it was in there, I decided to change out to Pro-Filer 195CC heads, Edelbrock RPM performer and a 1" spacer. Everything else remained the same. Well, everything except the converter that you helped me out with, Tri-Shield 9.5" 3500. Very tight for getting about, instant flash to 35K when needed.
We slapped the motor in before paint and ran it a little bit. I noticed that I had to increase the angle of the primary blades to keep it running. Mixture screws had little to no effect. At the time I'd figure I would deal with it later.
Well later is now. I figure with the added flow and assuming air velocity, I'll probably need more of both idle air and fuel. Before I go digging into this too deep and leaning over fresh fenders and such, I was wondering what your thoughts are on the changes needed for this increase in flow.
I'll add a gratuitous car picture once I figure out how.
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What 1" spacer, 4 hole, fully divided, fully open, semi-open?.....
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it's a 4 hole Mr. Gasket - https://www.summitracing.com/parts/mrg-3406?seid=srese1&gclid=CjwKCAjw8symBhAqEiwAaTA__GC_Slj7t_ZUYZGt82_mPwx9KogBnPZlWgCayYTAbZbdSvWFVGShWRoCeQ4QAvD_BwE
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The reason I went with a 4 hole is that I thought it would leave the pulse signals the same. Apparently I am wrong. I should have researched this site a bit more rather than thinking I knew what was needed. It seems that I would be better off with an open spacer or no spacer at all. I would like to read your thoughts though on the science behind it.
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I have done EXTENSIVE testing with spacers and before I go any further I'll simply say that most folks reading this are NOT going to like my results.
I've tried them on the street, dyno, and at the track, on several different engine/drivetrain/vehicle combo's and remarkably came up with the same results every single time.
The spacers tested were 4 hole, fully divided, fully open and semi-divided (open between the secondaries only.
First you have to divide the testing into two categories. Single plane intakes and dual plane intakes.
Single plane intakes absolutely LOVE at least a 1" spacer and often work very poorly without one leaving a LOT of power and vehicle performance on the table. They like fully open spacers the best and one that is nicely blended into the plenum area.
Dual plane intakes do NOT like spacers much. Fully open and four hole were the WORST when we tested them. We saw some power on the dyno with fully divided and semi-open spacers. However at the track we saw losses in 60' and short times that were NOT made up by a slightly stronger top end charge.
I'll also add here that anytime we had to use a drop base or air cleaner assembly that moved the lid closer to the carb we LOST power and vehicle performance, far more than was added by installing the spacer.
Anyhow, it would take many pages to cover all the testing, but for the most part they are a waste of time/funds on most set-ups they end up on. To this day I chuckle to myself when I walk thru a car show and see how many people have installed them on engines making a lot less power than the ones we tested them on, and think that somehow they are helping them out someplace.......FWIW.....
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That's one reason we bought property WAY out in the country back in 2003 and built our shop out here. There isn't anyone close enough to us so that we're bothering anyone running loud engines and such.
Back when I lived in Pittsburgh Pa there wasn't a week went by someone didn't call the Moon Twp Police and have them pay me a visit for doing exactly what you were doing!.....Cliff
Haha... didn't know you lived in Pittsburgh. I grew up in the west end.