ICT 34 adjustments

[james_stan]

Hi All

Have only run the ICT34s for a few miles on a 1776 C25 CAM all else standard engine but it appears to be running a bit rich.

The idle/primary jets a 60s and teh mixture screw is out about 1.5 turns which I think is minimum
recommended according to Redline set-up. Idle speed itself seems fine and it also runs pretty good
too, but thr plugs are as black as your hat and it smell rich (although I suspect some fuel smell is from a perished breather..)

Do I need to knock it down to 55s ? I also read somewhere that setting the idle as low as possible
adjusts the butterfly so that it block off fuel 'holes and will lean it up too. Correct ?

Cheers all

JS ..

PS not yet taken it on a long (m-way) run to see if that lightens up teh plugs a bit

 

[67panel]

well you can only get a accurate plug colour if you give it a good full throtle blast and turn engine off before it idles ,so if you know a duel track with a laybuy thats the best.wats your dizzy 009?timing setting?will all make a differance.

 

[james_stan]

well you can only get a accurate plug colour if you give it a good full throtle blast and turn engine off before it idles

That's what I heard before - will try and do that soon and let you know the outcome.

Cheers

JS

 

[Geeze]

What fuel pump are you running?
Those carbs aren't big fans of too much pressure and it can make well jetted carbs appear to run rich....

 

[sparkywig]

What fuel pump are you running?
Those carbs aren't big fans of too much pressure and it can make well jetted carbs appear to run rich....

Yes, mine runs much better with a fuel pressure regulator fitted as even a stock fuel pump can push up to 8psi.

 

[james_stan]

Hi all

Thanks for the replies. I did a plug chop after a decent run/quick stop and
the electrode was nice and brownish. However at idle it still looks/smells rich.

The pump is stock newish Brosol. I was going to order some 55 idles anyway
but perhaps I could try a regulator - is 3 PSI the going rate ?

Cheers

JS

 

[moler]

I've heard that brand new ICT's aren't jetted for a 1600 bus engine, even though sold as such, so need rejetting (smaller).

 

[sparkywig]

I've heard that brand new ICT's aren't jetted for a 1600 bus engine, even though sold as such, so need rejetting (smaller).

If you've got a 1970's Bedford CF van then they're perfect....


The jets as supplied are;
idle jet 52
main jet 130
air corrector jet 160
emulsion tube F78
needle valve 175

Laurie Pettit recommends these for a 1600 single/twin port
idle jet 55
main jet 150
air corrector jet 170
emulsion tubes F3/F6
needle valve 125-140

F3/F6 emulsion tubes have no drilling high up on the tube allowing the idle jet to do its job without adding early fuel from the main jet.

After much trial and error I've got the same jets fitted as Laurie recommends, but fitted a fuel pressure regulator set on 2.5psi and kept the 175 needle valves.

 

[james_stan]

Hi Sparky

Mine was a redline kit on a 1776 so not set-up too bad I think. Of course before I fitted them
I did write down the jet sizes but naturally I've lost the piece of paper! These idles (60s)
are the originals so it's not quite as CF van spec.
I've read some of Lauries advice on Vzi so willing to take heed of it.

Cheers

JS

 

[Geeze]

Hi all

Thanks for the replies. I did a plug chop after a decent run/quick stop and
the electrode was nice and brownish. However at idle it still looks/smells rich.

The pump is stock newish Brosol. I was going to order some 55 idles anyway
but perhaps I could try a regulator - is 3 PSI the going rate ?

Cheers

JS

No need to splash out on a regulator to set up a stock pump: beg / steal / borrow a fuel pressure gauge (you would need to do this to dial in a regulator anyway, so no extra bother) and then if you've got too much pressure, just shim the pump out by putting some extra gaskets underneath it. From memory, each gasket drops the pressure by about 0.3 or so