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#1073837 - 05/06/22 06:51 PM Modifying CCC systems for performance  
Joined: May 2007
Posts: 5,105
Buick Runner Offline
10+ Year
Buick Runner  Offline
10+ Year
Member

Joined: May 2007
Posts: 5,105
Dharma station 1 the Hydra
There are some myths going around that you can' t get high performance while retaining the CCC systems. This is hogwash being parroted by lazy people who don't want to perform research. Qjet guru Cliff Ruggles stated that E4ME are excellent carburetors and that he has setup MCSSs with CCC into the 12's and even high 11's. So CCC is hardly a performance shackle. He also states there is no reason to go to older non CCC Qjets to improve performance given the chosen cam makes enough vacuum. One just has to be intelligent with camshaft choice. Cliff warns that many aftermarket cams have excessively tight LSAs that leaves a lot of power off the table, especially for street cars.

E4MEs are more identical than different from older Qjets, the idle and secondary setups are highly similar. Nearly all Qjets have borderline lean idle circuits for the stock camshafts. Again Cliff states that any camshaft change will require idle circuit modifications for most Qjets.Displacement, compression ratio, heads, camshaft, ignition timing, etc all affect the idle circuits. Another Qjet guru Sean Murphy gives similar advice for CCC Qjets about enriching the stock id9le circuits.Sean states the stock main jets in L69 carbs are ample enough for performance.

With modifying Qjet idle circuits, you want enough idle fuel so the mixture needles are effective and enough bypass idle air to keep the throttle plates at a low angle at idle to prevent main nozzle drip. Advancing the base ignition timing also helps to keep the throttle plates at a low angle. There are 4 calibrated restrictions in the Qjet idle circuit that must be measured and enlarged if need to enrich the circuit. These are the idle tubes, the down channel restrictions, the entry port to the mixture needles, and the the discharge ports into the primary bores. Sean also likes to enlarge the accel pump discharge ports to help improve off idle operation. Of course you need to be conservative with enlarging any orifices inside your carburetor. The idle tubes generally only need a .002 enlargement.

Cliff warns that later Qjets have very fine metric idle mixture needles that can require several turns for a reaction. Moreover, he also states that later Qjets have large idle transition slots that can feed a lot of fuel and can trick the user thinking the mixture needles are supplying enough fuel with the lean drop method. Worn throttle shafts, plates, or distributor shaft bushings can interfer with ifle adjustment along with vacuum leaks and worn fuel pump pushrods.

The secondarys fof E4MEs operate thd same as non CCC Qjets. Modifications here include swapping rods and hangers, adjusting the spring tension for the air flaps, drilling the the fuel and air pickup tubes, drilling the choke pulloff.

On the electronics side, there are a few improvements such as hotter tunes from PROM burning or swapping like the ZZ4 PROM and heated O2 sensor upgrade.

Last edited by Buick Runner; 05/06/22 09:51 PM.

SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1073839 - 05/06/22 11:02 PM Re: Modifying CCC systems for performance [Re: Buick Runner]  
Joined: May 2007
Posts: 5,105
Buick Runner Offline
10+ Year
Buick Runner  Offline
10+ Year
Member

Joined: May 2007
Posts: 5,105
Dharma station 1 the Hydra
Here are a few resources to help modify your Qjet.

Doug Roe's book on Qjets.

https://www.amazon.com/Rochester-Carburetors-Revised-Doug-Roe/dp/0895863014

Cliff Ruggle's book on Qjets.
https://www.ebay.com/itm/4028821010...SZFtLAJ0PxYmInz-msbX-_8zkoRoCQtQQAvD_BwE

An Article about Sean Murphy modifying a MCSS Qet.
https://www.ebay.com/itm/4028821010...SZFtLAJ0PxYmInz-msbX-_8zkoRoCQtQQAvD_BwE

Another article featuring Sean Murphy performing more extensive modifications on a CCC Qjet for a Camaro Z with Twisted Wedge heads.
https://www.smicarburetor.com/ecom/download/Chevy_Hi_Po_Elec._Qjet_9-07.1.pdf

Some threads from Cliff's Qjet forum.

https://cliffshighperformance.com/simplemachinesforum/index.php?topic=651.0
https://cliffshighperformance.com/simplemachinesforum/index.php?topic=4262.0
https://cliffshighperformance.com/simplemachinesforum/index.php?topic=1497.0

Here is a handy drill size chart.

[Linked Image]

Last edited by Buick Runner; 05/06/22 11:03 PM.

SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1073858 - 05/08/22 03:13 PM Re: Modifying CCC systems for performance [Re: Buick Runner]  
Joined: Jul 2020
Posts: 67
69hurstolds Offline
Member
69hurstolds  Offline
Member

Joined: Jul 2020
Posts: 67
Aiken, SC
Good info.

The first Sean Murphy article link is of Cliff Ruggle's book, so not sure what article you originally intended. Probably a copy/paste error.

Although that old CHP article from 2007 was decent considering the amount of space they had to work with, it was not accurate in a couple of places. The carb they were working on was a 3-point adjustment carb with separate lean/rich stops. One of the pictures said the rods hung from the paddle plunger which is incorrect. They actually are spring loaded to open fully and are simply held down to the proper position by the paddle plunger. Also, they pointed to the rich stop and incorrectly called it a rich/lean stop. 2-point adjustment carbs came with a rich/lean stop that was adjustable, but the rich stop was fixed height above the lean stop as they were adjusted together. The lean stop is the screw that holds down the solenoid in the correct adjusted position so when the plunger is pulled in, it closes the metering rods to the proper "closed" position. Keep in mind the CCC system cycles those rods up and down all the time. The dwell of the off and on of the solenoid is what determines how much fuel is delivered to the engine based on all the inputs to the ECM. So it works a bit differently than the old vacuum operated primary metering jets.

The solenoid lean stop is best adjusted by a height gauge that comes in the J-33815 carb adjustment kit. It's 1.304" tall and sits on top of the main jet. Thus, there's a hole in the center to allow it to sit on top of the main primary jet securely. You can maybe make one yourself by taking maybe a 1/4" aluminum tube and cutting it to 1.304" exactly. The other dimensions of the gauge are 0.219" OD, and 0.169" ID for the hole that goes in about 0.818" deep on one end. If you have some digital or dial calipers, those would come in real handy to measure the dimensions.

Like maybe it can be made by using this tubing below. I've never done it myself as I already have the specialty tools, but the dimensions are pretty close. OD= 0.25", ID= 0.180"

https://www.amazon.com/Precision-83...&hvtargid=pla-908718667845&psc=1

The 3.5 turns out from bottom on the lean stop adjustment method MIGHT work, if the 3.5 turns equates to that 1.304" space. Otherwise you may or may not be where you want to be. You're making a "window" of range for the metering rod travel, but you also want the travel to be adjusted for the proper fuel flow during the dwell cycles. So it's important to start with the gauge height on the lean stop first during assembly, remove the rich stop from the top of the carb and remove the lean stop and rich stop plugs in the air horn to allow for adjustments on the car. Again, you'll need a specialized tool to do any adjustments of the lean and rich stops once the top is back on (tool J-28696-10 or equivalent). Then you set the rich stop to obtain 4/32 (1/8") target total paddle travel, or whatever is specified for your particular application. There's different ways to get there, but GM recommends using the slightly filed down Kent Moore float gauge measuring method to measure the total paddle plunger travel. Remember to replace the plugs when completely done as those plugs will retain the adjustments as well as cover up the holes. Especially the lean stop hole as it would be open to atmosphere otherwise, leading to dirt entry, or fuel control issues if not plugged.

Once you get your engine where you want it to be, then worry about your CCC carburetor mods. If you plan on upgrades later, make sure you can get those adjustments to be able to work with your new engine upgrades. Otherwise, you're marrying your carburetor to the engine mods you dialed it in to be. The CCC carbs are pretty responsive and a bit adjustable within reason, but 25-35 degree dwell (always shoot for 30) on the mixture control solenoid is your friend.

This sheet belwo should give you an idea of how to set up the MCS and air bleed valve adjustments on the bench prior to making any final adjustments on the car. There is a specialized tool for measuring the idle air bleed bench setting, too. On the car, the final idle air bleed valve is dwell set depending on if it has a letter stamped in the top or not. Extra step for the letter type. TIP: tiny springs on primary metering rods. When removing, be extra careful not to lose them.

[Linked Image]

#1073859 - 05/08/22 04:35 PM Re: Modifying CCC systems for performance [Re: Buick Runner]  
Joined: Jan 2000
Posts: 5,609
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 5,609
Pottstown, Pa
Here is what I think is the bible on setting up a CCC primary side to factory specs. Although the Dualjet is the two barrel CCC version of the four barrel the setup and operation of the primary is identical.
http://tocmp.com/manuals/Carbs/Rochester/DualJet/E2M/service/1980DualJetE2M.pdf

Yes there is nothing in that manual about modifying the primary side for more fuel flow when changing engine demands it does tell how to get to that correct starting point for a "factory" rebuild.

Years ago when the CCC was running on the 305 in the 86 an effort was made to improve the pri side performance. At the U-pull-It every CCC i ran across in the yard, primarily the Dualjet cars, were pulled apart and the pri jets and rods were "taken". I didn't feel bad about that because absolutely no one was in the yard shopping for a Dualjet on a V-6. They crushed cars after 30 days sitting in the U-pull there.
What i found was most all V-8 CCC 4 barrels used a 56 or 57 pri rod. From the Dualjets I pulled others rod sizes, .049, .052, .053, .056, .057, .060, .062.
A set of the .053" rods i ran in SS carb for years. What i found was that improved part throttle response for just a second until the slow CCC processor caught up the increased richness and initiated the 14.7 rule. But the rod change was noticeable.
Bob

#1073860 - 05/08/22 07:05 PM Re: Modifying CCC systems for performance [Re: 69hurstolds]  
Joined: May 2007
Posts: 5,105
Buick Runner Offline
10+ Year
Buick Runner  Offline
10+ Year
Member

Joined: May 2007
Posts: 5,105
Dharma station 1 the Hydra
Originally Posted by 69hurstolds
Good info.

The first Sean Murphy article link is of Cliff Ruggle's book, so not sure what article you originally intended. Probably a copy/paste error.

Although that old CHP article from 2007 was decent considering the amount of space they had to work with, it was not accurate in a couple of places. The carb they were working on was a 3-point adjustment carb with separate lean/rich stops. One of the pictures said the rods hung from the paddle plunger which is incorrect. They actually are spring loaded to open fully and are simply held down to the proper position by the paddle plunger. Also, they pointed to the rich stop and incorrectly called it a rich/lean stop. 2-point adjustment carbs came with a rich/lean stop that was adjustable, but the rich stop was fixed height above the lean stop as they were adjusted together. The lean stop is the screw that holds down the solenoid in the correct adjusted position so when the plunger is pulled in, it closes the metering rods to the proper "closed" position. Keep in mind the CCC system cycles those rods up and down all the time. The dwell of the off and on of the solenoid is what determines how much fuel is delivered to the engine based on all the inputs to the ECM. So it works a bit differently than the old vacuum operated primary metering jets.

The solenoid lean stop is best adjusted by a height gauge that comes in the J-33815 carb adjustment kit. It's 1.304" tall and sits on top of the main jet. Thus, there's a hole in the center to allow it to sit on top of the main primary jet securely. You can maybe make one yourself by taking maybe a 1/4" aluminum tube and cutting it to 1.304" exactly. The other dimensions of the gauge are 0.219" OD, and 0.169" ID for the hole that goes in about 0.818" deep on one end. If you have some digital or dial calipers, those would come in real handy to measure the dimensions.

Like maybe it can be made by using this tubing below. I've never done it myself as I already have the specialty tools, but the dimensions are pretty close. OD= 0.25", ID= 0.180"

https://www.amazon.com/Precision-83...&hvtargid=pla-908718667845&psc=1

The 3.5 turns out from bottom on the lean stop adjustment method MIGHT work, if the 3.5 turns equates to that 1.304" space. Otherwise you may or may not be where you want to be. You're making a "window" of range for the metering rod travel, but you also want the travel to be adjusted for the proper fuel flow during the dwell cycles. So it's important to start with the gauge height on the lean stop first during assembly, remove the rich stop from the top of the carb and remove the lean stop and rich stop plugs in the air horn to allow for adjustments on the car. Again, you'll need a specialized tool to do any adjustments of the lean and rich stops once the top is back on (tool J-28696-10 or equivalent). Then you set the rich stop to obtain 4/32 (1/8") target total paddle travel, or whatever is specified for your particular application. There's different ways to get there, but GM recommends using the slightly filed down Kent Moore float gauge measuring method to measure the total paddle plunger travel. Remember to replace the plugs when completely done as those plugs will retain the adjustments as well as cover up the holes. Especially the lean stop hole as it would be open to atmosphere otherwise, leading to dirt entry, or fuel control issues if not plugged.

Once you get your engine where you want it to be, then worry about your CCC carburetor mods. If you plan on upgrades later, make sure you can get those adjustments to be able to work with your new engine upgrades. Otherwise, you're marrying your carburetor to the engine mods you dialed it in to be. The CCC carbs are pretty responsive and a bit adjustable within reason, but 25-35 degree dwell (always shoot for 30) on the mixture control solenoid is your friend.

This sheet belwo should give you an idea of how to set up the MCS and air bleed valve adjustments on the bench prior to making any final adjustments on the car. There is a specialized tool for measuring the idle air bleed bench setting, too. On the car, the final idle air bleed valve is dwell set depending on if it has a letter stamped in the top or not. Extra step for the letter type. TIP: tiny springs on primary metering rods. When removing, be extra careful not to lose them.

[Linked Image]




Not sure how that link got messed up but here is the corrected link for Sean Murphy working on a stock MCSS Qjet.
https://www.motortrend.com/how-to/ccrp-0908-qjet-carburetor-rebuild/

Cliff Ruggles has mentioned a few times that modern ethanol gasoline formulations leans out the fuel mixtures. So even with bone stock engines, the borderline lean idle circuits may still require some enlarging to compensate for the ethanol. Plain carb rebuilds don't always fully resolve problems, sometimes you have to modify a few things even in stock applications.

Keep in mind the adjustments mainly affects mixtures, not volume going into the carb. Carefully enlarging the circuits allows for more volume while maintaining the same mixture through the adjustments. At idle a little air flows past the closed throttle plates, additional air from the throttle bypass system, and air / fuel mixture out of the idle needle discharge ports. These 3 elements combine into the final idle air / fuel charge. The off idle slots act as airbleeds at closed throttle but become fuel mixture discharge ports when the throttle plates are cracked open a little to let in additional air / fuel mixture into the charge. As the throttle plates open, the lowest pressure point shifts from the idle ports under the plates, past the off idle slots, and finally to the main discharge ports.

Last edited by Buick Runner; 05/08/22 09:32 PM.

SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.

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