Tuning 4AGE Webbers

[75Ta22LT]

Hi Everyone.

Just wondering what simple processes anyone goes through in trying to gain a smooth idle with webbers. I KNOW that ill never get it perfect on this bitch as its got lumpy ass cams but I'd like to try.

Ive been to alot of sites out there and have got the general jist of what to do, however theres always hints and tricks lurking out there so I thought id put the question up in the air.

Basically, the engine was running with the idle mixture screws 4+ turns away from closed. Which is probably why the plugs where fouling up so quick.I have reset these to 1 turn from closed and the car idles a shitload better already (aka doesnt just die with no throttle).

Fresh fuel was put in yesterday and ill be finding some new plugs asap.

Checked the linkages for stickyness, reset the butterfly position to fully closed.

Still got a vacuum leak so theres no real point trying to tune it to much untill thats fixed.

Timing is 14 degrees right?

Anything Else????

[takai]

Timing is 10* BTDC not 14. 12* i found gives a good little bump in power, but i wouldnt go much further.

[Munki]

If you have a vacuum leak fix that first, as you said there is no point in doing anything until thats fixed.

next step would to make sure all the passages in the idle circuit are clean and the jetting is correct.

then balance the carbs. I always used a balance gauge (the onese that go over the throat). turn the idle speed up to 2-2.5k to get some airflow happening and then balance.

reset idle speed and reset timing

then play with your idle screws, a good place to start is 2.5 turns from closed.

re check your timing and then your done

this is a brief guide as to how i have done it on both webers and solex i had. Just on a side note the solex kept in tune much longer than the webers

hope this helps

Daniel.

[nb86]

follow munki's directions, and mine from your previous post.
12 - 14 desgrees is about right for webers at idle, but don't exeed about 32-34 at WOT and not below about 3000rpm.
BTW what sort of ignition are you running? if it's the standard ecu set the timing at 12 degrees BTDC.

[75Ta22LT]

NO ECU whatsoever

HEC (or MEC!?!?) 715 Bosch coil.

Recommended a MEC716B (make much diff???)

32-34 at WOT --- WOT???

Gonna rip the carbs off this arvo and see if I can redo the sandwhich plate seals. Been shopping around canberra for new seals but this'll do for the moment.

[takai]

715/716 is only the snout type. They are made for different spark plug leads, but no body difference. WOT is Wide Open Throttle.

[Munki]

you say no ecu? just curious how you are controling ignition a MSD 6a or something?

also in reguards with the seals on the carbs sounds like you dont have soft mounts for the carbs. This is most probably the cause of your vacuum leak.

soft mounts are your best friend with dcoe's so if you dont already have some get them!

Daniel.

[takai]

Vac advanced dizzys, they produced them for the 4AGE for a while.

[Screamn_Sleeka]

You need to choose you idle jets before u start playing around with 'tuning'
40 or 45 idle jets are good for 1600's, check what you have, its probably a complete mismatch.

You don’t want to be adjusting the idle very much, it should be able to idle well with the idle jets only, you will get terrible fuel economy if your idle is accelerating too much because you will be effectively using another 2 jets per throat (2x4=8).

[75Ta22LT]

As far as i know its a vac adv dizzy, however ill check this out asap, theres 4 wires coming from the coil, 2 go to the dizzy so ill trace the other 2.

Ive got $600 worth of receipt for the carbies being overhauled. Im pretty sure they are the soft mounts however its DEFINITELY leaking off of 3 cylinders (spray wd40/carbi cleaner over the seals and the idle goes all haywire).

MEC716B - B for ballast resitor????

Unfortunately it wasnt me that built the engine or id be able to throw all the ignition specs out there.

however -

16v 4age bigport (88kw)

High comp pistons

HIGH degree cams (gets there at 6500rpm)

tuned 4-1 extractors

port+polish

Dual 42 DCOE webbers (unmatched pair)

[Munki]

yeah 45 idle jets with f9 tubes would be my guess on a set of 40's

edit i just saw you had 42's that are mismatched sounds like you could be in a world of pain.

42's with a cam that 'comes on' at 6500 is not a good combo.

["Z" UTE]

75Ta22LT, if you run into any drama's with the tuning, contact Steve Millar, or Roger McConachie from the Canberra Celica Group.

Rog does a lot of carb tuning, and Steve millar has a real "ear" for side draught carbies.

cheers Chuck.

[Ben Wilson]

I'd be very surprised if the cams are really that big. I think with proper tuning you'll find a much wider power band.

[Screamn_Sleeka]

34mm main venturi's will JUST do for a 6500rpm 1600cc, and thats the max size for 42's.
Unless ur restoring a maserati people usually stick to 40s or 45s.

[poida]

Good info, my twin solex's need a tune also.

Sorry for the slight hijack but, I was wondering where i might be able to get a new diaphram for my 2tg dizzy as mine is punctured? I have asked around and i've been told to try and match it with a newer item, any ideas?

Or if cant a a new part, who in SA can reco?