Cliff's Quadrajet Parts and Rebuild Kits
Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: hiy_po on October 17, 2019, 04:57:19 AM
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Looking for advice to setup my Quadrajet 17059596.
I have a 3.3litre 202 ci Inline 6 cyl Holden engine.
It kind of looks like a smaller version of your Chev inline 6's.
It runs a Rajay Turbo draw threw turbo system. I have a Quadrajet 17059596 It is modified to reference the power piston from after the turbo and has a one way so dos not blow into the power piston.
Some engine specs - After market Alloy head 12 port 1.5 ex 1.7 in 70cc chamber
.462 valve lift LC 112 with a 1.65:1 roller rocker
7cc dish tops 7.3:1 c/r
Ignition is via an ECU fully adjustable with MSD 6AL igniter and MSD coil Blaster 3
5 speed manual 3.08:1 LSD diff
My progress so far
FIRST Carb (Stage Two Ver 3)
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Idle Down tibes 1.6mm 0.064' #52 top 1.2mm 0.046' #56 bottom
Idle Down-Channel Restriction 1.59mm 0.062' #52
Idle Discharge tube 3mm 0.118' #32
Upper Idle Air-Bleed 0.4mm 0.18' (Air horn)
Upper Idle Air-Bleed 1.78mm 0.070' #50
Lower Idle Air-Bleed 2.2mm 0.087' #44
Idle Air By Pass throtle plate outlet 2mm 0.079' #47
Main Air-Bleed Airhorn 2.3mm 0.090" #43
Primary Jet 0.073
Primary Rod o.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods 0.044 inch tip “DA” code
Secondary hanger bracket B
Measurements in mm then thou then Index size if known.
My progress so far
FIRST Carb (Stage Two Ver 3)
________________________
Idle Down tibes 1.6mm 0.064' #52 top 1.2mm 0.046' #56 bottom
Idle Down-Channel Restriction 1.59mm 0.062' #52
Idle Discharge tube 3mm 0.118' #32
Upper Idle Air-Bleed 0.4mm 0.18' (Air horn)
Upper Idle Air-Bleed 1.78mm 0.070' #50
Lower Idle Air-Bleed 2.2mm 0.087' #44
Idle Air By Pass throtle plate outlet 2mm 0.079' #47
Main Air-Bleed Airhorn 2.3mm 0.090" #43
Primary Jet 0.073
Primary Rod o.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods 0.044 inch tip
Secondary hanger bracket B
Measurements in mm then thou then Index size if known.
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It runs but Idle is lean, Idle mix screws are 3.5 turns out and carb does respond to them, Touch throttle and goes rich.
Idle stop screw is about 2 and a half turns out.
0.067" #51 I think is what will work for IDCRs
I have two Upper Idle Air Bleeds 1) from throttle bore to Idle down channel on a downward slope.
2) In Air horn see attached pic.
Should I block the top ones?
I would need to know the specs in thousands of the following items.
The idle tubes (bottom or restriction at the end of them)? - 0.046' #56 bottom
Lower idle airbleeds? - Lower Idle Air-Bleed 0.087" #44
Upper idle airbleeds and location? (There should only be one pair either just above the DCR's or in the airhorn, not both) - I have both see above Upper Idle Air-Bleed 0.18' (Air horn)
Upper Idle Air-Bleed 0.070' #50 IDC.
Main airbleeds in the main casting? - unkown look small in a brass bleed.
Main airbleeds in the airhorn? - 0.090" #43
if I am doing something that isnt the best, would like to hear about it.
Things that matter, Engine is low compression and is 10/12 Hg at Idle.
Is a 3.3 inline 6 cyl.
My aim. Get good fuel economy for long trips but have 12s AFR at WOT with Boost.
My theory
Need large jets and orifices to counter low vacuum, but 6cyl doesnt need the same amount of fuel as a V8 so highly sensitive but low volume supply.
Things I dont know and would like to,
The Idle tubes, should I be opening the bottoms of the idle tubes and leaving top of tube standard?
Will opening the Air-Bleed to the main circuit in the venturi have more effect than opening the one in the air-horn?
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My settings mm removed
Idle Down tibes 0.064' #52 top 0.046' #56 bottom
Idle Down-Channel Restriction 0.062' #52
Idle Discharge tube 0.118' #32
Upper Idle Air-Bleed 0.18' (Air horn)
Upper Idle Air-Bleed 0.070' #50
Lower Idle Air-Bleed 0.087' #44
Idle Air By Pass throtle plate outlet 0.079' #47
Main Air-Bleed Airhorn 0.090" #43
Primary Jet 0.073
Primary Rod o.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods DA 0.044 inch tip
Secondary hanger bracket B
Needle seat 0.130
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Main Air Bleeds (In the main casting) - 0.025"
Drilled my IDCR - 0.067 #51
Measured the Main Air Bleeds in the Main casting while I had top off.I have a 0.026 Bit so am thinking will use it while apart. So upgrade that size -
Main Air Bleeds (In the main casting) - 0.026
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Just went for test drive, mains are still rich and Idle mixture screws are 3 1/4 turns out, Throttle stop screw is about 2 turns out Idle is around 950 rpm and close to stoich maybe 14.2:1 AFR.
I am noticing I dont seem to get a leaner cruise with some manifold vacuum, seems not much if any difference between driving at 4Hg and 1psi Thinking need to hit the main air bleed in the main body with the next drill size up.
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Where I am at
Idle Down tibes 0.064' #52 top 0.046' #56 bottom
Idle Down-Channel Restriction 0.067' #51
Idle Discharge tube 0.118' #32
Upper Idle Air-Bleed 0.18' (Air horn)
Upper Idle Air-Bleed 0.070' #50
Lower Idle Air-Bleed 0.087' #44
Idle Air By Pass throtle plate outlet 0.079' #47
Main Air Bleeds (In the main casting) - 0.026
Main Air-Bleed Airhorn 0.090" #43
Primary Jet 0.073
Primary Rod o.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods DA 0.044 inch tip
Secondary hanger bracket B
Needle seat 0.130
Float setting 0.240.
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Not sure why your LIAB's are .087". That is HUGE and will cause a pretty big leak-path and reduce "pull" on the DCRs's, idle tubes,etc. Then you have two pairs of upper IAB's?
That will require a big idle tubes and DCR's, and probably not the best set up for the little 6 cylinder engine.
You only need one pair of upper IAB's. I'd rather see the LIAB's reduced to .070", block off the UIAB's in the main casting, and open up the UIAB's in the airhorn to .040".
Then you can use small idle tubes, and much smaller DCR's and bring in PLENTY of fuel at idle and to the transfer slots for improved off idle transition.
A few Q-jets were used on smaller CID engines, specifically the Pontiac OHC in line 6's from the 1960's. Those carbs have very small idle tubes, DCR's, and tiny IAB's. They work quite well on those engines and I'm sure the factory used the smaller specs for a reason.......Cliff
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OK that will give me something to do tomorrow. Will try and make those changes.
My thinking was I have very low vacuum at Idle so need things open up big to get the fuel flowing.
I will try peen the LIAB closed a bit and redrill to 0.070 If I cant peen them maybe try to melt some lead into the holes and redrill.
I can lead fill the UIAB in the main body, blocking them and resmooth and drill the holes in the Air-horn to 0.040
I was just experimenting but can see why I joined because I do need some guidance.
And you are correct about it pulling hard. It looks like my AFRs are close but it just kept picking up speed evenly it is missing the hard pull. The push back in the seat is not there.
Once I have it to your specs will test it again and re think the Idle tubes and IDCRs
Thank you for taking the time to read and comment.
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Rather than trying to peen them smaller get some 6-32 brass setscrews for the lower bleeds 8-32 for the DCR.
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Well I tried to peen, was getting to awkward and difficult, so lead filled it, the lead fell out when I drilled it. so yes it is now fitted with a Brass bush. I have one in but looks like I am going to have to make it smaller as it looks like its blocking half the passage.
Those Brass grub screws are incredibly hard to get in Aus. Something so simple you can walk into a corner shop and buy are not available here. I have searched EBay and online, I have found suppliers in USA but this is the message I get when I try to order them
Cancelling Your McMaster-Carr Order on 10/06
Contact photo
From McMaster-Carr
To hiy_po@hiy-po.com
Date 2019-10-07 21:26
Message Body
Hi Adam,
Thank you for considering McMaster-Carr for your purchase. However, we will not accept orders from your location due to the cost of complying with US export regulations.
Andrew
Have found another place as well with branches in US and Canada, I cant even get an account because I am in Aus.
And our dollar is incredibly weak, what costs $US10 costs me $AU60 delivered.
I have one other Question is my carb an 800 CFM casting?? Looks like it has the lumps.
Tried to take a pic but turned out blury. Took some othe pics of progress.
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800 CFM cast main body ??
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have you tried going to a local machine shop and seeing if they have or can get the hardware you need? I would do this before looking online personally.
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I dont live near a city, I live rural WA about 4 hours out of Perth. Its an hour away to nearest machine shop and they can supply grub screws but not in Brass.
I can not get Brass 6-32, 8-32 or 10-32 cup point set screws locally or online.
Only way I can get them is if Cliff wants to sell me some or someone wants to send me some, I will quite happily pay for a bag of 50 of each.
I may be needing a new set of Gaskets as mine are looking very used so maybe if I order some gaskets can order some screws as well.
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I need the next step in setting up this idle circuit as its Idling very rough and have no control at all with Idle mixture screws. Seems to be running richer as well. I do notice when secondaries kick in it pulls harder. But need some idle control back please. My guess is smaller bleeds are pulling more threw the big IDCR and Idle tubes. But will wait to hear it and what sizes are recommended.
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Her ya go everything you need.
https://www.mcmaster.com/brass-set-screws
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Cancelling Your McMaster-Carr Order on 10/06
Contact photo
From McMaster-CarrAdd contact
To hiy_po@hiy-po.comAdd contact
Date 2019-10-07 21:26
Message Body
Hi Adam,
Thank you for considering McMaster-Carr for your purchase. However, we will not accept orders from your location due to the cost of complying with US export regulations.
Andrew
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That's a bummer. If all you need is some set screws, I'll see what I have & could send you some in the mail.
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I dont know if I can do it, but if possible I would buy some and send to your address or any US address and get you to forward to me. I would just need to know postage costs and if you want a fee just add it on and can send you a payment by what ever method works.
This car is my daily driver and am out in the bush so I do need to get it going again asap. It is really running to rich now to drive.
If you do have half a doz 6-32 and maybe 4x 8-32 you have spare and could stick them in an envelope and send me I am at
Adam Hill
19 Monger street
Bencubbin WA
Australia 6477
It is absurd That I have been chasing these things for over a month and cant get them.
I have used the mounts from an old computer mother board (see pic) to do the LIAB, and made my MAB adjustable as well. but am out of them nowl. The original MAB look to be the same as the IDCR's so have soldered the bottom and drilled to 0.040. Just waiting on Cliff to give me a size to Take them to and I can get this thing at least good enough to drive.
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Cliff
is there any chance I could get a spec sheet or a link to what the small cubic inch motor Quadrajets were setup like. I have searched but with the exception of a couple articles that dont go into detail I cant find any thing. It would ne extremely helpful to know what these factory carbs were set to. With my low compression I dont expect they will work perfect in mine but it would be great to have a base.
I need to order a gasket set and some grub screws to.
And what size should I have my IDCRs drilled to?
Thanks.
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I'll see what I have, I should have at least that many. We'll give it a try.
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Wow I thought I finally had some until I added shipping
1 bag 25 screws
1 bag 30 screws
$US171
Good grief.
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We ship overseas daily, typically about $18-24 to most places if the weight is less than 2 lbs.
I also stock screw in and drive in air bleeds....
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OK so what do I do just go on the website and click away??
Will go look now. By the way I bought another Quaddy today but a pre emission one I think without the APT. Just got to wait for the post man to bring it.
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Do you want the screws from me or do you want to see what Cliff can do for you?
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I cant actually see them on his website???
I will grab a basic kit and screws if can find them but dont seem to be there.
If You still send me some let me know what you send and will buy them off Cliff to send to you to replace what you send. If that just isnt a logistic nite mare in the making.
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I cant list my self as Australia it only gives me USA option
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OK I'll get em out today 6/6-32 & 4/8-32.
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Thanks heaps. If I cant get anything else at least I will have them.
If I cant get any any other way I will buy from them and send to you.
MSG from ASMC
Is it seriously $US137 to ship two small bags of Brass set screws?
9:40 PM
Hi Adam,
the freight is what it is. If you have a forwarder in the US, you can always ship the order there (free), maybe they will give you a better deal than $137 for this small amount of material.
Thanks
Alex S.
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Let me know when or if you get the screws, PO said could take up to 2 weeks.
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I sat down today and had a good think about how this carby works, I drew up a picture of the Idle system and had a good hard look at it. It I am now thinking the Lower Idle air bleed is actually bleeding off the vacuum from under carby that pulls the Idle mixture threw the Idle system. The bigger the bleed the more the Idle down channel restriction needs to be open to compensate for less vacuum which means more fuel being pulled threw for Idle. I want less not more. So reduced the Lower Idle air bleed from 2mm down to 1.65 mm, This one change increased the vacuum on the whole Idle circuit so reduced the Idle Down Channel restriction from 1.7m to 1.2mm to pass less fuel down to the Idle mixture screws and closed the Idle jet at the bottom of the Idle tube from 1.3 mm to about 0.8mm. The theory is that once it comes off Idle onto the main circuit the small jet will not allow alot of fuel to mix in with the main system which is a more efficient fuel supply. The main system is better at emulsifying the mixture than the Idle system so I want that to be supplying the fuel not the Idle system.
On start up it idled well. Idle mixture screws are only out about 1/2 a turn out from fully seated and throttle stop screw is about 1 turn open, which suggests it is still pulling plenty of fuel from the Idle circuit. Got it to Idle as low as 600rpm but was a bit rough and was happy at around 800rpm. but was still showing rich. I want the Idle to go lean of stoich so thinking I can still go smaller just keep all three settings even untill the Idle mixture screws need to come out more than 3 turns, that would suggest The fuel coming threw the Idle circuit is getting low.
Quick drive down the road and back and transition seems good, no stumbles or spit backs but cruise is still rich so that is also suggesting I am still getting an excess of fuel from the Idle circuit mixing with my mains. Be interesting to see how far I can reduce it and if I see the mains go leaner as I do..
Thanks Cliff for your advice on the Lower Idle Air Bleed being a leak and they are setup smaller for a reason. I think I am getting alot closer now.
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Where I am at
Idle tubes 0.067" top 0.031" bottom
Idle Down-Channel Restriction 0.047"
Idle Discharge tube 0.118"
Upper Idle Air-Bleed 0.040" (Air horn)
Upper Idle Air-Bleed body blocked
Lower Idle Air-Bleed 0.065"
Idle Air By Pass throtle plate outlet 0.079"
Main Air-Bleed Airhorn 0.079"
Main Air-Bleed body 0.040"
Primary Jet 0.073
Primary Rod 0.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods 0.044' tip inch “DA” code
Secondary hanger bracket B
Needle-Seat 0.130"
Float setting 0.250.
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Too ambitious ?? How small can you go?
Have the Idle tubes down to 0.023 jet. They look pretty small.
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If you are using a .065" LIAB and .040" upper in the airhorn it will not need a lot of idle tube to put plenty of fuel to the mixture screws and transfer slots.
Marine carburetors used a similar set-up as they were not emission calibrated. They also use very small idle tubes and generous idle fuel at the mixture screws.
It's remarkable how responsive Marine carburetors are if you test one.
If you look all the way back to early production Q-jets, you'll also notice that early units thru 1967 will also use less idle air and smaller idle tubes.......Cliff
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OK I'll get em out today 6/6-32 & 4/8-32.
Thank you. They look alot better than my home made ones.
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My latest carb setup
FIRST Carb (Stage Two Ver 6-1)
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Idle tubes 0.063" top 0.024" bottom
Idle Down-Channel Restriction 0.041"
Lower Idle Air-Bleed 0.054" #54
Idle Discharge tube 0.118"
Upper Idle Air-Bleed 0.040" (Air horn)
Upper Idle Air-Bleed body blocked
Idle Air By Pass throttle plate outlet 0.079"
Main Air-Bleed Airhorn 0.064" #52
Main Air-Bleed body 0.040"
Primary Jet 0.072
Primary Rod 0.048
Custom: / (2-5) / 0.900' spring
ATP 2 turns up.
Secondary Metering Rods 0.044' tip inch
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I did a trip yesterday. 200 km round trip.
Was happy with approx 17litres/100km highway travel. I use 98ron pump gas.
I do seem to have a lean cruise. At very light throtle, low load, level cruise the AFR meter goes off the scale lean. Still seems to cruise ok if maybe a little hesitant.
Adjustment to APT does nothing as Vac is about Zero or even possibly just positive.
Have I created a gap between main and idle circuit???
Am thinking slightly enlarging IDCR will allow more idle system fuel to be added longer maybe bring it back on to the scale at least, or be better to just go up one jet size. it does make sense to me to try close the gap with the mains system rather than Idle system.
It is worth saying that engine didnt have any bad effects from it running lean. just really good fuel economy.
Will also try going to blocked Idle by pass air as that controlled air leak may be contributing to the lean.
Current recipe
FIRST Carb (Stage Two Ver 6-3)
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Idle tubes #52 0.063" 1.61mm top
#73 0.024" 0.61mm bottom
Idle Down-Channel Restriction #59 0.041" 1.1mm
Lower Idle Air-Bleed #54 0.054" 1.4mm
Idle Discharge tube #32 0.118" 3.0mm
Upper Idle Air-Bleed #60 0.040" 1.0mm (Air horn)
Upper Idle Air-Bleed body blocked
Idle Air By Pass throtl plate #68 0.310 0.79mm
Main Air-Bleed Airhorn #70 0.0270 0.68mm
Main Air-Bleed body #60 0.040" 1.0mm
Primary Jet 0.070
Primary Rod 0.048
Custom: / (1-4) / 0.900' spring soft thin wire
ATP 4 turns up.
Secondary Metering Rods 0.044' tip “DA” code
Secondary hanger bracket M
Needle-Seat 0.130"
Float setting 0.250.
Idle Screw 2 turns out
Throtle stop 2.5 maybe 3 turns
Am I using the smallest Cubic Inch engine on the site??
Any other 6 cyls ??
Still havent bought another pump but may do it at end of week.
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Tune for results not what a gauge is showing you. If you are lean to a point where the engine doesn't like it, at light throttle for example, the engine will surge, lack power, "flat" with a little throttle movement, or even backfire up thru the carb if it gets way too lean. So basically in certain scenarios you may see really lean on a gauge but the engine load is light enough it doesn't care.
Every engine has slightly different requirements across the load/speed range but most will like similar numbers as a general rule. Don't forget about ignition timing, especially the amount added by the vacuum advance. It is a load sensing device and designed to add timing when engine load is light and engine vacuum is high. This allows us to burn a much leaner mixture all else being equal, so don't forget to use it as part of your tuning......Cliff
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Am I using the smallest Cubic Inch engine on the site??
Any other 6 cyls ??
Still havent bought another pump but may do it at end of week.
Is that in a VK? Looks like a black motor.
Sound like you almost have it sorted.
I am enjoying reading the progress.
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Yes VK with a black motor 3.3
Quick question I am sorting the secondaries and have backed off the tension that holds the secondary air flaps closed until I am getting a slight cough back and splutter as I open the secondary throtle plates. Now I know I can just tighten them up again to get rid of it but I do want them open asap. Can I enlarge the secondary enrichment to compensate for the earlier openning of the air flap ??the secondary enrichment outlet seems to be about #70 0.028thou at the inner restriction.
Thanks.
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I prefer to use a timed choke pull-off to keep the flaps from "whipping" open too quickly vs spring tension. What I don't know is how intake pressure from using a turbo effects the drop in vacuum seen on N/A engines that allow the pull-off to dampen then fully open progressively based on the size of the restriction being used in it.
I wouldn't open up the POE system any if at all, at least not until you make sure the pull-off can't be used to delay the opening just long enough it prevents a lean condition. POE fuel comes in pretty quickly, and the fuel in the main passages leading to the secondary nozzles adds some fuel as well going quickly to full throttle.
Since it isn't using an accl pump there is a very slight delay for POE so using the pull-off to hold things back for just an instant really helps. There is of course some accl pump shot left over from the primary side to help out as well, so shorter pumps over there increase duration helping out even more......
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Had to strip it down for some turbo repairs. Made a start up video once had it all back to gether. Idles average of 600 to 650 rpm does drop as low as 500 rpm. enjoy.
https://youtu.be/F4uTnM00Yas (https://youtu.be/F4uTnM00Yas)
I was thinking if I was to use the Pull off would use the same boost ref line the power piston is using. Havent put the pull off back on yet but may do if I get the hesitation or stumble back as secondary air flaps open. Is hardly noticable atm.