Carbureting the 4AGE essentials

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dr.occa
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Base Jettings (DCOE style) for stock 4AG motors

Postby dr.occa » Wed Aug 28, 2013 7:24 am

Phil, I forgot to mention that the above jettings are geared for "Power" rather than all around driving and where peak power is at 5500.

Here are more base jettings:
If other jettings share the same size(s) as the previous sets then I've omitted them. Please reference the set above the one you are currently electing to use for any missing jet sizes.

Jetting sets for all around driving will be in green.

Jetting sets for power will be in red.

rpm: 5000
all around driving
chokes/inner venturis: 26
idle/pilots: 45f9
mains/secondaries: 105
air correctors: 160
pump jets: 40
emulsion tubes: F11/F15/F9/F16

rpm: 5300
all around driving
chokes/inner venturis: 27
mains/secondaries: 110

rpm: 5500
all around driving
chokes/inner venturis: 28
mains/secondaries: 115
air correctors: 160

rpm: 6000
all around driving
chokes/inner venturis: 29
mains/secondaries: 120
air correctors: 170

rpm: 6300
all around driving
chokes/inner venturis: 30

rpm: 6500
all around driving
chokes/inner venturis: 31
mains/secondaries: 125

rpm: 6800
all around driving
chokes/inner venturis: 32
mains/secondaries: 130
air correctors: 180
emulsion tubes: F15/F9/F16

rpm: 7000
all around driving
chokes/inner venturis: 34
mains/secondaries: 140



rpm: 5000
power
chokes/inner venturis: 28
idle/pilots: 45f9
mains/secondaries: 115
air correctors: 160
pump jets: 40
emulsion tubes: F11/F15/F9/F16

rpm: 5300
power
chokes/inner venturis: 29
mains/secondaries: 120
air correctors: 170

rpm: 5500
power
chokes/inner venturis: 30


rpm: 6000
power
chokes/inner venturis: 31
mains/secondaries: 125
emulsion tubes: F15/F9/F16

rpm: 6300
power
chokes/inner venturis: 32
mains/secondaries: 130
air correctors: 180

rpm: 6500
power
chokes/inner venturis: 33
mains/secondaries: 135

rpm: 6800
power
chokes/inner venturis: 34
mains/secondaries: 140

rpm: 7000
power
chokes/inner venturis: 36
mains/secondaries: 145
Last edited by dr.occa on Wed Sep 13, 2023 5:49 am, edited 1 time in total.

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Fri Aug 30, 2013 11:20 pm

Soooo in lieu of all that, I'm finally to that tuning/test drive stage of my carb swap, keep in mind I've got Weber 45 DCOE's on a red top small port hi comp. My current settings here in PHX are:

- 35 chokes
- 70 IDLES!!!!!!!!!
- 150 mains
- 195 airs
- 45 pumps
- F16 emuls

I mean PHX does have high levels of ethanol in our fuel, guessing anywhere from 8-12%, but 70's freakin really?! MSD 6AL2, run retard set from 0-1000 curving 5-10deg BTDC, from there it curves up to a max of 30deg by 4500. Now, I got the carbs w/ 45 idles, got it to fire, sync'd n idling but when I snapped throttle it fell flat on its face. Roll into it slowly n she runs like a raped ape! Top end seems there or at least close. Tried 50's n 55's, nope... Got 60's n 65's, freakin awesome getting closer, like off idle if I laid into it she'd drop out. 70's are sooooo close but something still ain't right.

Current idle needle settings are:
-1. 3/4 out
-2. 7/8 out
-3. 1 1/8 out
-4. 5/8 out

Current idle screw settings don't make sense at all, but I think I got the EGT's somewhere around 60deg of variance from front to back. Speaking of which, does 550-600+deg taken at the exh man at the head, sound too hot? Either which way, a wideband is in the works very soon. In the mean time, I'm gonna do an ignition tune up on it, chk the old plugs, run compression n leak downs again, n order air filters.
Here's a teaser, build thread in the works...

Image

In this...

Image
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Re: Carbureting the 4AGE essentials

Postby Phil Bradshaw » Sat Aug 31, 2013 1:35 pm

Thanks Gents,

Scored a t50 yesterday with a quick shift. May have lead on an AE86 big port complete so may end up going that way instead of small port. Phil..

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Re: Carbureting the 4AGE essentials

Postby s24a » Mon Sep 09, 2013 6:29 am

dr.occa wrote:Phil, your name sounds so familiar.


Dr. Occa...

Maybe you heard of Phil from HERE?

http://home.clear.net.nz/pages/phil.bradshaw/Index.htm

Phil has a great background in transplants and conversions of Toyotas.
Also great info on adapting EFI on engines.......
"When the going gets, wierd, the Wierd turn Pro" -- Hunter S. Thompson

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Re: Carbureting the 4AGE essentials

Postby dr.occa » Sat Sep 14, 2013 9:17 am

s24a wrote:
dr.occa wrote:Phil, your name sounds so familiar.


Dr. Occa...

Maybe you heard of Phil from HERE?

http://home.clear.net.nz/pages/phil.bradshaw/Index.htm

Phil has a great background in transplants and conversions of Toyotas.
Also great info on adapting EFI on engines.......


Yep, that's where! Thanks for the jog s24a.

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Re: Carbureting the 4AGE essentials

Postby lukeruss » Tue Nov 12, 2013 12:43 am

Hey guys was wondering if you could help me out with a few questions.
I have a smallport 4age and I am in the process of fitting it with twin 45 carbs and putting it in my ke70.
I've read up a fair bit about the ignition setup on this forum and only found that you can use either a modified 4k dizzy or the dizzy out of a bluetop 4age with a msd setup.
I am wanting to go down the road of msd but havent found any info about if I can use my stock smallport dizzy with an msd setup.
If you can't use smallport dizzy with msd would you know if bluetop dizzy fits into smallport head without any mods?
I emailed msdignition directly but have not heard back from them.
Any help is greatly appreciated.

Cheers.

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Wed Apr 02, 2014 11:19 am

lukeruss wrote: I am wanting to go down the road of msd but havent found any info about if I can use my stock smallport dizzy with an msd setup.


I dunno but good question. I got one at the house, so I'll open it up when I get home n let u kno.

lukeruss wrote: If you can't use smallport dizzy with msd would you know if bluetop dizzy fits into smallport head without any mods?


It does. I've got a small port red top and I'm running a blue top dizzy. The main thing is that u tap into the lower/inner pickup coil that's at the 4 point rotor. Trust me, I initially hooked in to the TDC pickup and was left scratching my head as to why it wouldn't start till I figured it out, "oh duh..."

I do have questions for the Doc or anyone else running the 6AL-2, what's ur timing locked out at? What's ur ignition map look like? Reason I ask is that I apparently got mine locked out at 37deg BTDC and the most Run Retard you can get outta the 6AL-2 is -25deg. Therefore, the lowest I can dial back timing to start and at idle is 12deg BTDC. Help plz? Mahalo's in advance
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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Sat Apr 05, 2014 2:57 pm

Found this, thought I'd share

http://joltfreak.tripod.com/id28.html

Very comprehensive but as far as selecting idle jets, they recommend much smaller ones than I'm currently running. Of course, it will vary from elevation to elevation as well as state to state due to varying octane levels as well as ethanol content. Good reading tho
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Re: Carbureting the 4AGE essentials

Postby dr.occa » Sun Apr 06, 2014 7:56 am

808AE86inAZ wrote:I do have questions for the Doc or anyone else running the 6AL-2, what's ur timing locked out at? What's ur ignition map look like? Reason I ask is that I apparently got mine locked out at 37deg BTDC and the most Run Retard you can get outta the 6AL-2 is -25deg. Therefore, the lowest I can dial back timing to start and at idle is 12deg BTDC. Help plz? Mahalo's in advance


What's wrong with 12 degrees BTDC at idle? What exactly is it that you're wanting to do?

The programmable 6AL-II is going to give you the control you need to properly manipulate your timing.

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Re: Carbureting the 4AGE essentials

Postby Gregxster » Thu Apr 10, 2014 9:13 pm

My first post... I've been lurking around this forum for over a year. I am installing a Blue Top 4age and 5spd trans into my 1969 Triumph Spitfire! At first I was planning on using the stock fuel injection system. After looking at the complexity of the FI system and having to install a high pressure fuel pump and fuel return, I've decided to install a pair of Weber 40mm DCOEs. Check out my build journal: http://www.triumphexp.com/journal/Gregxster

I just purchased a Redline Weber DCOE kit off ebay from John's Foreign Engines, aka "My4n". It was a bit pricey but I wanted new, clean, properly jetted (or at least close) setup. The kit was dropped-shipped directly from Redline and was here in 2 days!

A couple of comments on the manifold:
The casting is a bit "rough". It can easily be filled or ground down to smooth out the casting edges. The manifold fits my "big port" head very well. The ports and bolt holes line up Okay, but the port edges will need to be cleaned up. The mating surfaces are flat and square. I am planning on cleaning it up and powder-coating it. I will post pix later...

QUESTION! I will be using my stock distributor and need to know which 2 wires (red-white or green-black) to hook-up to the coil? I have a MSD 6a and will be adding a timing controller. I won't have it running for a few months, the car is almost ready for the body shop!

Gregg

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Re: Carbureting the 4AGE essentials

Postby dr.occa » Fri Apr 11, 2014 4:35 am

Gregxster wrote:...

QUESTION! I will be using my stock distributor and need to know which 2 wires (red-white or green-black) to hook-up to the coil? I have a MSD 6a and will be adding a timing controller. I won't have it running for a few months, the car is almost ready for the body shop!

Gregg


This might help.

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Re: Carbureting the 4AGE essentials

Postby demby123 » Tue Apr 22, 2014 6:00 am

I'm in the process of installing a 4age with a set of Yamaha 600r bike carbs into my sr5. Looking at the carbs I just noticed the throttle wheel is much smaller than my sr5's aisin carb. Anyone here running bike carbs have a short gas pedal?

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Wed May 07, 2014 7:44 pm

dr.occa wrote:What's wrong with 12 degrees BTDC at idle? What exactly is it that you're wanting to do?

The programmable 6AL-II is going to give you the control you need to properly manipulate your timing.


Ok so the 6AL2 only has -25deg of run retard. From what I've found thru trial n error, is that the Bluetop dizzy has 13 teeth, thus each tooth is 27.69deg. This is hard to put into words so bear w/ me. While trying to lock out the dizzy I found that one tooth back dizzy set to full advance, max timing was 22-23deg BTDC but I could achieve single digit timing at idle where it runs smoothest. But 23deg at WOT, c'mon... Ok so one tooth fwd, dizzy set to max retard is 37-38 BTDC, thus max run retard achieved via the 6AL2 is 12-13deg BTDC at idle.

Honestly, I was chasing a runs rough at idle and severe hesitation at off-idle/tip-in and I thought at the time it was attributed to timing. I just got er back from being tuned at a local VW shop and it's 95% better! They changed to smaller idles, smaller mains, smaller air correctors, and different e-tubes. It idles a little high but smooth, AFR's are a little high but safe, overall drivability and power are great but there's still an occasional intermittent slight and brief hiccup/hesitation. I'm really happy with it tho, I can't wait to put miles on it.

My current settings are:
55 idles
140 mains
160 airs
F7 emuls
45 pumps
35 chokes

Thx for all the help Doc, u rock!
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Re: Carbureting the 4AGE essentials

Postby dr.occa » Thu May 08, 2014 8:18 pm

Glad she's running better for you. 13 tooth!? You must be sporting a high-comp dizzy. The factory largeport dist should have a 4 point trigger wheel. That's the one you would want to hook up to your 6AL mag pick-up leads. Makes a world of difference believe me.

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Re: Carbureting the 4AGE essentials

Postby totta crolla » Fri May 09, 2014 12:52 pm

I'm guessing the 13 teeth refers to the drive cog on the base of the distributor.

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Fri May 09, 2014 3:45 pm

totta crolla wrote:I'm guessing the 13 teeth refers to the drive cog on the base of the distributor.


Yah, that's what I meant...

dr.occa wrote:Glad she's running better for you. 13 tooth!? You must be sporting a high-comp dizzy. The factory largeport dist should have a 4 point trigger wheel. That's the one you would want to hook up to your 6AL mag pick-up leads. Makes a world of difference believe me.


Thx Doc! Yessir, got a brand new Bluetop dizzy in it n MSD pickup is wired to the lower 4 point trigger. Lol, when I initially wired it up I had it tied into the upper TDC trigger n it wouldn't start :oops:
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Re: Carbureting the 4AGE essentials

Postby demby123 » Sun May 18, 2014 6:47 pm

Managed to get my 4age started up and running today but with a bit of a problem, it runs lean as hell and pops through the carbs with any sort of throttle. I'm thinking the main jets would be the cause since idle is mostly fine. Idle jets may come in handy too though since the idle mixture screws are out a good 6-10 turns.

The mains that came in the carbs were keihin 155s IIRC (I still have them in a bag with the car at the moment so i'll have to verify that tomorrow) And I switched them out for 160s. Since keihin jet #160 should be 1.6mm I and the recommended drill size for most bike carbs on a 4age is 1.6 or so mm I figure it would work, but most engines running bike carbs use R1 carbs which are bigger in bore size and are used with a bigger 1L engine, so mabye 160s are a bit too small for mine, which come off a yamaha 600r.

https://www.youtube.com/watch?v=HL-uNMXSYsQ
https://www.youtube.com/watch?v=UgfkifkiiUk

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Re: Carbureting the 4AGE essentials

Postby ogdougynutty » Sun May 18, 2014 7:46 pm

Your main jets are not the problem, mains only deal with 3/4 - full throttle. From the video it looks like your barely touching the throttle, and that is all through your needle jet/jet needle. The needle jet/jet needle control your fuel from about 1/4 ~ 3/4 throttle.

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Re: Carbureting the 4AGE essentials

Postby demby123 » Mon May 19, 2014 4:59 am

ok, it goes lean at full throttle as well, but I haven't given it too much throttle since the engine is on a fresh rebuild and it was still warming up at the time. Damn I don't want to wait another week for jets to come in... I might be able to shim them a bit.

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Re: Carbureting the 4AGE essentials

Postby demby123 » Tue May 20, 2014 7:40 pm

I fixed the issue on throttle, I only wanted to run it for a little while so I let the fuel pump fill the bowls and cut it off and forgot it was off... :roll: kept it running and it revs but runs a bit rich at times then lean. The real confusing part is, while driving it down the street to see how it would react with a little load on it, throttle leans out and when you lift off throttle, it goes rich. And when idling it will start off at around 14-14.9 and slowly get richer and richer. I've also tried shimming the needle jets but that just makes it run a bit too rich on part throttle. Things are getting a bit confusing but I'm not giving up on this...


The fuel pump is leaking fuel so for now I'll have to wait for a new one to come in and start over once I get that in...

Heres were I am now...
https://www.youtube.com/watch?v=MqLUUL0D2zo&feature=youtu.be

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Re: Carbureting the 4AGE essentials

Postby ogdougynutty » Tue May 20, 2014 9:29 pm

Well as long as it is drivable it should be good, once you get you fuel leak fixed go out and drive it. Because the AFRs will be different with load on the motor.

The usual way with these, you do the mains first then work your way to the needle settings. And the lift off "richness" is normal.

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Re: Carbureting the 4AGE essentials

Postby demby123 » Tue May 20, 2014 9:55 pm

ogdougynutty wrote:Well as long as it is drivable it should be good, once you get you fuel leak fixed go out and drive it. Because the AFRs will be different with load on the motor.

The usual way with these, you do the mains first then work your way to the needle settings. And the lift off "richness" is normal.

Is there any way to reduce the rich mixture on liftoff? Kills the engine braking a bit. I'd assume i'd have to lean out the idle a bit?

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Re: Carbureting the 4AGE essentials

Postby demby123 » Mon Jun 23, 2014 8:21 pm

Haven't replied in a while because of silly crap that keeps popping up preventing me from working on the car. So far everything's working much better than it was, there was some lean out at high rpm/ high throttle but after researching for a bit I found out where the air correctors were for these carbs, which control AFR at high rpm( Didn't think there were any on these). I blocked them off and the leanout went away but it ran pig rich at higher rpms so I put together a little setup similar to this to control it better. Unfortunately my MTX-L decided to die right as I began testing, so that will have to wait.

In the mean time I'm still trying to figure out why revs cut out at around 5500rpm. Timing light shows it cutting spark completely at that rpm rather than retarding ignition at the correct rpm set in the megajolt. I don't have a hard rev limiter and according to autosportlabs, the EDIS shouldn't have a built in rev limiter at all... :?

https://www.youtube.com/watch?v=4UwTzCyCgJQ

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Re: Carbureting the 4AGE essentials

Postby Devinmockk » Sun Sep 07, 2014 4:10 pm

Hey guys I'm doing a carbed swap on my 85 sr5 and I'm using a pair of delotro 40s and I just have a 3 rib bluetop. Where can I find a manifold? I've been looking the last couple of days and I haven't been able to fine any for a decent price.

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Re: Carbureting the 4AGE essentials

Postby El Gato Felix » Thu Sep 18, 2014 11:26 pm

I read the ignition essentials part, but didn't see anything about what type of spark plugs can be used. I was wondering what type of spark plugs would be best when running carburetors e.g. Mikuni, Keihin, FCR, Yamaha....... I'm currently using NGK V Power with my carburetor setup, and I'm wondering if I could I benefit from an Iridium spark plug..?? Is anyone using Iridium with their carburetor setups..?? Any input or opinions appreciated, Thanks :)

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Re: Carbureting the 4AGE essentials

Postby allencr » Fri Sep 19, 2014 12:47 am

El Gato Felix wrote:...I'm wondering if I could I benefit from an Iridium spark plug..??


NO, unless you're only looking for very long replacement intervals.

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Tue Nov 18, 2014 10:32 pm

Do chokes affect idle and off idle performance or drivability? I got 35's in a set off DCOE 45's and contemplating running 30's or 32's…
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Re: Carbureting the 4AGE essentials

Postby tiprock » Wed Nov 19, 2014 6:10 pm

808AE86inAZ wrote:Do chokes affect idle and off idle performance or drivability? I got 35's in a set off DCOE 45's and contemplating running 30's or 32's…


if your 4ag is close to stock, 34mm is supposed to be ideal.
since you have webers, this is a good book:
http://www.amazon.com/Build-Dellorto-Carburettors-SpeedPro-Series/dp/1903706750/ref=pd_sim_b_3?ie=UTF8&refRID=17BD05HH92XVSY42Y7SG
zenki levin hatch
kouki trueno coupe

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Thu Nov 27, 2014 2:46 pm

A word to the wise. If/when using the MSD Tach Adapter, do not mount it in the passenger compartment… the buzz it creates is annoying as all hell! Jus moved mine out to the eng conpartment today, SOOO much better!!!
Step 1: Remove head from ass.

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Re: Carbureting the 4AGE essentials

Postby 808AE86inAZ » Fri Jul 17, 2015 11:35 pm

Ummm… I killed a Carter in tank pump in almost 600mi exactly?!?!?! It's REEEEAAALLLY "warm" out here in PHX right now, thought I had vapor lock somehow after parking it. Got it home somehow, chk'd er after a few days, 0psi fuel pres, 12vdc at the tank, OFL fuel pump resistance?! Banged it on the ground, 3.9ohms, I'm sure it'd run again but F that, stuck a new one in… besides the singing alternator bearings, you tell me https://youtu.be/iQtGOzgZdC0


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Step 1: Remove head from ass.

ay fu@k u ok, u don't kno me bra

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