Author Topic: modifying E4ME carb need advice  (Read 3756 times)

Offline 454scotty454

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modifying E4ME carb need advice
« on: September 10, 2011, 01:14:44 PM »
Cliff,
   Here is the stock specs I pulled off of my carb:
Idle tube - didn't remove yet
idle down channel 0.0465
lower idle air bleed 0.076
upper idle air bleed (main casting) 0.033
Accelerator pump discharge holes 0.024
main air bleed (main casting) 0.120
main air bleed (air horn) 0.116
idle screw holes 0.0635
idle bypass air 0.0635
secondary accelerator well holes 0.038
secondary accelerator discharge holes 0.042
air flap 1.415
   This q-jet is going on a HT383 which is mild and pulls good vacuum. According to the first recipe, i should open up the upper idle air bleed to 0.070, open idle bypass air to 0.080, mixture screws to 0.090. The main air bleeds are huge, should I reduce these?
This is my gameplan for tuning this carb, please correct me if I am wrong. After resizing, set the rich and lean stops to the factory setting. Use the idle bypass air to tune the carb to 30 degrees dwell, if this does not work resize the main air bleeds smaller. Then adjust the idle mixture screws.
Cliff I bought your rebuild kit and just doublechecking the specs before I modify the carb.
Thanks for any and all help

Offline Cliff Ruggles

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Re: modifying E4ME carb need advice
« Reply #1 on: September 23, 2011, 04:35:09 AM »
The CCC carburetors have an adjustable upper airbleed system, leave the upper airbleed stock.

I wouldn't go too big on the holes under the mixture screws either, as the screws may not have enough threads to full seat if you get the holes too large.

It may not come in range with the large main airbleeds.  We have drive in bleeds if you need to richen things up some?.....Cliff

Offline 454scotty454

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Re: modifying E4ME carb need advice
« Reply #2 on: September 30, 2011, 07:54:56 AM »
Cliff,
    Thanks for the heads up!!! I was going to hog out the idle mixture screw holes. I ended up drilling to 0.076 inch, from stock 0.0635 inch. I think its a tad too big, as when I seated the screws and tested them with solvent it slowly leaked. I think it should be OK though.

Could I just swap a pre-CCC carb baseplate to get the normal idle mixture screws instead of the fine metric idle mixture screws on the later CCC carb? I was thinking a 78-80 baseplate.

I'm almost done with the rebuild. I have all the factory tools (thanks ebay!) and set the carb back to factory specs according to the factory service manual. I'll let you know if I need smaller main air bleeds.

THANKS!!!!

Offline Cliff Ruggles

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Re: modifying E4ME carb need advice
« Reply #3 on: October 02, 2011, 04:40:04 PM »
The baseplate will be fine, none of them form a perfect seal.  If the screws weren't bottoming out, solvent would be rushing past them during testing.....Cliff

Offline 454scotty454

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Re: modifying E4ME carb need advice
« Reply #4 on: December 15, 2011, 08:57:49 AM »
Cliff,
   I got the carb running. With the enlarged idle mixture screw holes being 0.076 inch from 0.0635 inch, i needed 7 turns out from seated to get the dwell in the right range (bench set idle air bleed screw). Do you think that is too far out? I was debating if I should go a little bigger so I do not have to turn them out that far. You also said that these mixture screws are metric fine pitch, so I should be OK. The carb runs fine so I am leaving it as is for now.
Thanks for all the help!
Scott

Offline Cliff Ruggles

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Re: modifying E4ME carb need advice
« Reply #5 on: December 16, 2011, 03:49:09 AM »
7 turns isn't really that far out, considering the fine pitch threads, taper of the mixture screws, and how small the hole is under them....Cliff