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  #21  
Old 04-09-2009, 08:12 AM
The PIG Smith's Avatar
The PIG Smith The PIG Smith is offline
King Browless
 
Join Date: Nov 30, 2001
Location: Fort Wayne, Indiana
Posts: 6,525
Nice posting...great information...

<mini-hijack>
While I may have the skills to modify a carb meant for a small block Ford, I do not have the experience.
I am looking to make my J10 a semi DD with some trail riding from time to time.
What off-the-shelf 4BBL carb would you fellows recommend?
I was thinking of either a Holley Truck Avengeror but thought myabe that would be overkill for mostly street use.

...or would someone like to mod one of these SBF carbs and sell it to me?
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2005 Grand Cherokee Limited - HEMI! Current Daily Driver
1982 J10: Current Project, goal to be roadworthy in 2017: No Cab Brow!
1981 J20: Commercial flat bed. Long term Project: RUST! No Cab Brow!

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...but if it works, I wouldn't touch it.
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  #22  
Old 04-09-2009, 09:52 AM
Ristow Ristow is offline
 
Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
Posts: 17,047
truck avenger is a very good carb. spendy too. you can get a 4180 ,put a kit in it with a new throttle shaft for 75-100bucks.

i'd do one up for you. would not have the secondary block though,unless you bought 2,i have no spare blocks.
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I LOVE how Ristow has stolen my comment about him ... "Quoted" it ... and made himself famous for being an ***hole to people. Hahahahahahahahahha!


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  #23  
Old 04-09-2009, 10:23 AM
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smearig smearig is offline
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Join Date: Dec 20, 2007
Location: Austin, TX
Posts: 240
Quote:
Originally Posted by The PIG Smith
Nice posting...great information...

<mini-hijack>
While I may have the skills to modify a carb meant for a small block Ford, I do not have the experience.
I am looking to make my J10 a semi DD with some trail riding from time to time.
What off-the-shelf 4BBL carb would you fellows recommend?
I was thinking of either a Holley Truck Avengeror but thought myabe that would be overkill for mostly street use.

...or would someone like to mod one of these SBF carbs and sell it to me?

My Edelbrock 1406 seems to be working fine and all I had to do was adjust the idle out of the box. My friend has a brand spanking new 670 Truck Avenger for sale if you're interested.
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  #24  
Old 04-29-2009, 06:01 PM
Ristow Ristow is offline
 
Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
Posts: 17,047
Some advanced tuning.

well,after spending some time playing with the jetting,i found myself stuck choosing between 2 jetting scenarios',and i didn't like either.

i've seen 3 different #'s on the jets in these 4180's. 209,309 and 602. 602 is supposed to be a close tolerance #60. i assume the other 2 numbers are fords numbers for the same jet. problem is,a 60 main jet should have a .060" hole,and these are considerably smaller. a couple thou' smaller,which is a lot relatively speaking.

with the stock jetting,it cruised ok,slight surging. and it pinged when i got into the gas,and it lacked the punch when i really stepped into it. but it got real decent mileage.

so i stepped it up several sizes on the mains,and the punch returned. the pinging stopped too. the mileage ceased as well.

so,as it was i had 2 choices. good mileage with poor kickdown punch,and needing to retard my timing to avoid ping,further decreasing power. or,jet it up to have power,and losing economy.

i wanted the best of both worlds,and here is how it is done.

the main jets are what you cruise on. that is why jumping up on them killed my mileage. i drilled a set of stock jets out with a .059 bit,making a #59 main jet and installed them.

the fix lies in the PVRC's. Power Valve Resriction Channels. they are behind the power valve. these are the "second" set of jets that are allowed to deliver fuel when the power valve opens.



i measured the PVRC's on a couple metering blocks i had around,from 600 and 750 cfm holleys. they range from .051 to .063. so,that means when the power valve opens,it's like having a second et of jets,sized 51 to 63,on top of the main jets,supplying extra fuel to the mix.



then i measured the 4180 block. they looked large. too large. a peak inside showed they were counter bored,and considerably smaller inside. to the tune of about .040. it's hard to see in the pic,you can barely see it. the inner hole is about half of the visible hole.



the fix is to open up the PVRCs',changing only the power jetting,not the cruise jetting.



i opened the PVRC's up to about .045-equal to about 4-5 jet sizes over the stock .040 holes,and the punch returned,and the pinging stopped,allowing my timing to be set to it's optimum setting. economy returned too. i'm getting consistent 13.5+ mpg. i'm going to jump up a bit more on the PVRC still though,.048-.050. it'll need it when the headers/dual exhaust go on.

this is the one and only place the Carter AFB design offers tunability over the holley. however,i want to stress this procedure is RARELY NEEDED on a holley. this carb was an emissions carb,hence the small channels. all you guys running universal holleys,like the 1850,3310,or avengers-DO NOT TRY THIS! it is almost 100% not needed in those models. once this procedure is done,you can't easily go back.
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Quote:
Originally Posted by Hankrod
Ristows right.................again,




Quote:
Originally Posted by Fasts79Chief
... like the little 'you know what's' that you are.




Quote:
Originally Posted by Fasts79Chief
I LOVE how Ristow has stolen my comment about him ... "Quoted" it ... and made himself famous for being an ***hole to people. Hahahahahahahahahha!


→ Where the kids hang out...

fsjbuilder.org come for the mindless chat,stay for the hand drawn emoticons.

It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
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  #25  
Old 04-29-2009, 06:53 PM
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jpcoutts jpcoutts is offline
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Join Date: Jun 28, 2002
Location: Hot Springs, Arkansas
Posts: 1,963
Great write-up! What is the best mileage you got during this process? What is your technique for drilling. I've never tried because I've been told such bad stories about drilling out jets.
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  #26  
Old 04-29-2009, 07:13 PM
Ristow Ristow is offline
 
Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
Posts: 17,047
13.6,according to my odometer,which i'd call a 13.5 overall average. keep in mind this is a mildly built stroker,with oversize valves and a tad overcam'd with rhoads lifters.not really a fuel efficient build,so at 13.5 i'm real happy. i drive it rather easy,but even driving easy it's fun,the torque is strong even then.

i used my dremel,which worked well,considering the angle it's at. a hand arbor would be ideal i s'pose,but a bit tedious,and since this is the enrichment circuit,it don't gotta be real precise. main jets are easy on the other hand.
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Quote:
Originally Posted by Hankrod
Ristows right.................again,




Quote:
Originally Posted by Fasts79Chief
... like the little 'you know what's' that you are.




Quote:
Originally Posted by Fasts79Chief
I LOVE how Ristow has stolen my comment about him ... "Quoted" it ... and made himself famous for being an ***hole to people. Hahahahahahahahahha!


→ Where the kids hang out...

fsjbuilder.org come for the mindless chat,stay for the hand drawn emoticons.

It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
Reply With Quote
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