• Carbureting the 4AGE essentials

Posted: **Wed Mar 13, 2013 6:10 pm**

eightsixgts wrote:Thanks for the response, I forgot to include the lift of the cams is 8.5. With the current idle jets I have now the idle is at a very steady 14-15AFR with the idles turned 1.75 out. When I'm in 5th gear cruising at 65mph with the stock 4.3 final I'm seeing AFRs around 12.5-13 which I really want to lean out. If I do the same 65mph in 4th gear I get a more comfortable AFR I'm actually looking for. I will actually be swapping to a 4.77 so maybe my issue won't be such a problem, but I still want to see if I can correct it a little bit. Tuning guides say you can get most carbs tuned to run well in a very general way, but if you're tuning for power, you're giving up mileage and drivability, and if you're tuning for mileage and drivability, you're giving up power. Oh well, I enjoy spending the time changing things up with these and taking notes so I'll be sure to continue to update with my findings.

12.5-13 AFR on your setup is prety good performance for a daily driver. Last time I tuned my car, my idle AFR jumped around in the mid to high teens but i was more focused at tuning WOT & 12.5 optimum was my goal which I eventually got.

My truck however, I had a really hard time dialing in my 3 circuit 750 dominator.. The AFR was never close to what my car was, & much like the dcoe's air restrictors, I had to open up the air bleeds quite a bit for each circuit..idle, intermediate & high-WOT, jotting numbers down & keeping track..it's a task & time consuming

Posted: **Wed Mar 27, 2013 4:44 am**

Hi, I am currently putting together my 4age with weber 40 dcoe's...they have 32mm chokes right now...is this the suggested size to use?

Posted: **Fri Mar 29, 2013 11:58 am**

amaze wrote:Hi, I am currently putting together my 4age with weber 40 dcoe's...they have 32mm chokes right now...is this the suggested size to use?

32mm will do just fine on a stock motor.

Posted: **Fri Mar 29, 2013 12:09 pm**

I was asked in another carb related thread to share the notes I took when I was looking around jotting other jet charts down. I took notes of peoples jet charts that were similar to mine from what I was able to gather going through the multiple pages on the old carb thread.

16v largeport
304/288 8.5lift
11.8:1 compression

My current notes are:
140main F16emul 195air
60/F9idle
45pump
no bleed

Grumpus(11:1 smallport 268 cams)
140main F16emul 230air
60/F9idle
45pump
?

Phogetful(Very similar to my build)
160main F16emul 180air
65/F9idle
40pump
no bleed

ZenkiSR5(Same build, different climate)
155main F16emul 180air
55/F9idle
40pump
modified progressive circuit(?)

Posted: **Mon Apr 01, 2013 11:26 am**

For your cam profiles and compression this is the ballpark I've come up with assuming 7000 is about the peak power (which is low for that high of compression and cam profile imo):

Chokes: 36
Mains: 145
Etubes: F16
Airs: 180
Idles: 45f9
Pumps: 40

Posted: **Fri Apr 05, 2013 5:18 pm**

They need to stickie this thread, TTT!

I picked up a T3 adapter, manifold, linkage n a used set of DCOE 45's, don't kno what size venturi's but they are missing 2 locking screws underneath

They came w/:

150 mains F16 emul 195 air
45 idles
45 pumps
No bleeds

Jus got um cleaned out n rebuilt, nothing's mounted yet, have yet to drop n clean out the fuel tank. I'm slacking hard, I kno... Not much of an update but it should start n run off of what I got, jus accumulating more parts for the build, TTT!

Posted: **Sat Apr 06, 2013 2:18 am**

I'm looking for a solution to fit a throttle position sensor to a set of weber 45dcoe's.
The problem I have is that there is not enough room to fit the weber tps kit on the end of the throttle shaft because
the cylinder head water outlet gets in the way, the only option I can see is to fit the tps onto the other carb but
that means the tps goes the wrong way and it won't turn.
Any ideas ?

Posted: **Sun Apr 07, 2013 7:59 pm**

Make a mounting plate for the linkage shaft and whittle/modify the end to work with your TPS.

OR

If you have room, try the 2nd carb (in between them).

Posted: **Sun Apr 07, 2013 8:02 pm**

808AE86inAZ wrote:They need to stickie this thread, TTT!

I picked up a T3 adapter, manifold, linkage n a used set of DCOE 45's, don't kno what size venturi's but they are missing 2 locking screws underneath

They came w/:

150 mains F16 emul 195 air
45 idles
45 pumps
No bleeds

Jus got um cleaned out n rebuilt, nothing's mounted yet, have yet to drop n clean out the fuel tank. I'm slacking hard, I kno... Not much of an update but it should start n run off of what I got, jus accumulating more parts for the build, TTT!

Run either 30 (5500 peak power) or 32 (6500 peak power) chokes.

Accelerator pumps should be 40s. Make sure to get your fuel pressure right (3.5psi, 4 really is noticeably too much. It was even for a 20R with a torquer cam).

Posted: **Tue Apr 09, 2013 9:55 am**

Ok, so when u guys are talking about chokes, ur referring to the auxiliary venturi's correct?

Posted: **Tue Apr 09, 2013 12:29 pm**

808AE86inAZ wrote:Ok, so when u guys are talking about chokes, ur referring to the auxiliary venturi's correct?

Posted: **Sun Apr 14, 2013 3:36 pm**

Did u guys cut/slim down oem engine harness or make ur own? Jus spent the last 2 days weeding thru my GTS eng harness for all the shyt I'm not using (fuel inj etc) & all the shtuff I'm gonna keep (oil pres, ect, starter signal, wipers n washer.) I did have ?'s on 2 wires tho, 1) B/R wire I'm assuming is power to ign switch, which comes from round black 1 pin connector under eng fuse panel & terminates at connector in pass side kick panel, 2) B/O wire, I'm assuming is main EFI pwr from ign switch, comes out of eng/body crossover connector & splices into eng harness a couple times???? 1) B/R I removed all splices & made one continuous wire from batt to pass kick panel. 2) I cut shy of where it entered the eng harness & spliced that into my msd ign pwr wire. Other than that it seems straight fwd, ign coil & distributor wiring comes from msd 6530, add tach adapter & that should be it, right? Questions, comments, concerns?

Oh & I got 35's for chokes btw... TTT!

Posted: **Wed Apr 17, 2013 8:49 pm**

It might be too late but it may have been better to keep the GTS harness unharmed by pulling it and grabbing SR5 harnesses. That way you can easily go back to EFI should you ever want to in the future.

Your essentials are lights, alternator/charging system, ignition, bypass AFM COR (circuit open relay) connection for the in tank fuel pump which can then be used for a low pressure, high volume, electric fuel pump. The bulk head connector at the firewall is central to a lot of things.

The EWD manual is a great friend to have. Check out AEU86.org for a link.

Posted: **Wed Apr 24, 2013 11:18 am**

I have just completed a 4AGE transplant into an MG Midget.
Large port Red Top,standard compression/cam profiles.Homemade exhaust headers.Distributor converted to house a Lucas 45d advance mechanism.Carbs are Weber 2x 40 DCOE 18, set up as follows;
36 mm chokes
2.00 air correctors
1.45 main jets
0.50f15 idle jets
4.5 pump jet
F15 emulsion tubes
Engine runs very sweetly.There is a little hesitancy when transitioning from idle circuit to main,a little lean on the idle jets I think.
The chokes are probably too big,I'm going to try 34mm and 4.5f9 idles.
Its certainly not far off the mark though I feel can be improved.
Good luck ,David
:mrgreen:

Posted: **Wed Apr 24, 2013 5:19 pm**

I have to rebuild my Mikunis. I took them off today since I ordered T3 injector plugs, I figured I'd clean and inspect them. I found the front carb would shoot gas out of both barrels like a champ, the rear carb did nothing. I took the float covers off, the front level would drop every time I pulled the throttle, rear never moved. Also the two check balls (called check balls in the manual but they are little barrels kinda) were stuck in the rear carb where someone tried to rebuild it and got RTV in the tubes. Gas shoots out of these with the float cover off on the front carb but the rear stayed dried. So I dumped all that mess out and flipped it over. All the linkage and external mechanisms seem to work fine. I pulled the pump covers off, the front one was near empty but the rear one was full. There you go, pump diaphragm in the rear carb is bad. I will do a full rebuild on both of them anyways; when I get a spare $150 to send to Wolf Creek.

But I'ma look hella dope with my T3 plugs! :lol:

Posted: **Thu Apr 25, 2013 4:43 pm**

Hey Dexter, yeah sounds like you're pretty close. Before switching out the chokes try 40 pumps. Going to smaller chokes will get you better low end response but rob you of top end power (if you're running mod to aggressive cams).

Carbd7age - yeah, I robbed my BT of a pair of freshly rebuilt Miks and slapped them on my 16v hi-comp to bring her back to life. Wow what a difference! You'll love it.

Posted: **Fri Apr 26, 2013 6:56 am**

dr.occa wrote:Carbd7age - yeah, I robbed my BT of a pair of freshly rebuilt Miks and slapped them on my 16v hi-comp to bring her back to life. Wow what a difference! You'll love it.

Carbs on a 20v? Please share pictures.. I've been debating this kind of project

Posted: **Fri Apr 26, 2013 5:37 pm**

eightsixgts wrote:
dr.occa wrote:Carbd7age - yeah, I robbed my BT of a pair of freshly rebuilt Miks and slapped them on my 16v hi-comp to bring her back to life. Wow what a difference! You'll love it.

Carbs on a 20v? Please share pictures.. I've been debating this kind of project

Here ya go.

Posted: **Sat Apr 27, 2013 4:18 pm**

I picked up a gallon pail of Gunk brand carb cleaner from the store today. Hopefully the main body will fit inside lol. It comes with a nifty small parts basket so you don't have to reach inside the pail for stuff.

Posted: **Mon Apr 29, 2013 6:30 am**

It's usually a pretty tight fit but you can get a stripped down Mik body in there sideways. If you want to do both simultaneously, pick up two gallons & one the autoparts store's empty buckets and fill it up with both gallons and plop both those Miks in there.

Posted: **Mon Apr 29, 2013 7:18 am**

The bucket is a smidge to small, but I reckon I can use a big C clamp to turn the bucket a little oval shaped and it'll plop right in lolzzz. I have all the small parts soaking right now. I gotta order some rebuild kits.

How do I know if I need to replace the needles and pump diaphragm? I know one carb wasn't pumping, but I think that was because of RTV gumming it up. Both diaphrams look good, they're flexible with no tears. And I reckon the needles are good cuz they move freely and the float.chambers fill up easy. I ask because a gasket kit is under $30/carb, but a full kit with needles and diaphragms is $75/carb.

Posted: **Mon Apr 29, 2013 4:59 pm**

When I took these carbs apart, the spring inside the accelerator pump, one was on top of the diaphragm, the other was below. I think that was my problem. I just need gasket kits now!

Posted: **Mon Apr 29, 2013 5:21 pm**

Yeah, I think all you need is just a gasket kit by the sounds of it.

You want to make sure the springs on the pump diaphragm are sandwiched between the metal disc of the diaphragm & the body of the lower block with the diaphragm piston being actuated by the pump lever.

Posted: **Mon Apr 29, 2013 5:46 pm**

Yeah I thought it was weird that the levers on the outside acted different. One was springy and the other didn't do anything.

Posted: **Tue Apr 30, 2013 4:13 pm**

Occa, thank you so much for sharing the carb manifold you found. I knew this would be one of the bigger hurdles of carbing a 20v. As far as ignition, I was hoping I could somehow use the OEM distributor the same way I'm using the bluetop distributor on my current 16v. Do you know if the 20v dist has a signal that can be used as a pickup for an MSD 6AL box? Also, how would you plan on going about utilizing VVTI if you weren't to use Megajolt? I've understood some people have used a window switch to enable it manually with carbs, but I'm open to other ideas as well. I'll probably be going through with a carbed 20v swap here soon now that things look much easier to work out than I always thought they were. 8-)

I think i'll put feelers out there for my 16v longblock now

Posted: **Tue Apr 30, 2013 8:42 pm**

If you prefer to stick with MSD than I highly recommend the programmable 6AL 2. It's about over $200 but it has a programmable ignition curve which you'll need though I can't say for sure that it'll work with the 20v dizzy.

As for energizing the vvt-i solenoid, unless the 6AL-2 has inputs/outputs for additional controls a momentary switch is the only practical solution at this point. One other idea is an on/off trigger that engages the solenoid as it monitors rpms.

Posted: **Thu May 09, 2013 4:57 am**

carbd7age wrote:The bucket is a smidge to small, but I reckon I can use a big C clamp to turn the bucket a little oval shaped and it'll plop right in lolzzz. I have all the small parts soaking right now. I gotta order some rebuild kits.

I have a pair of kits on the way! And I did get a carb body into the parts bucket. You gotta use a clamp or vise that opens a little wider than 6". Then just hammer the lid back on to round it back out.

Posted: **Sun May 12, 2013 9:22 am**

I got my kits, they don't come with the figure-8-shaped O-rings that seal the jet blocks to the carb bodies. I don't want to reuse them, especially since they took a bath in solvent for a couple days. I might have to anyways, and just use a dab of gasket sealant on both sides.

Posted: **Mon May 13, 2013 12:52 am**

Just another week or two and my EDIS set-up will be ready. Feels like christmas haha

Posted: **Mon May 20, 2013 5:17 pm**

Proud to say that my Carbed 4age is now apart of the Megajolt Community

Carbureting the 4AGE essentials

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