DCNFs on a T/C, advice needed please.

[Guy Croft]

Without a photo I'm struggling a bit, but yes, the cable should alwats be hooked up to the master carb which then actuates the slave in flawless synchronicity..

GC

[nickp]

Cracked it!!!
It was a combination of things on the linkage that were both causing the 'master' carb to be open a fraction. The spring on the quadrant arm and cable tension itself. Even though I'd isolated the spring before with a tywrap, I didn't realise it was then still open slightly due to the cable then going tight, because I was concentrating on the other carb I guess. So I've cured it by shimming the spring plunger so it's now only in light contact with the other carbs arm and adjusted the cable play once this was right. I've put the mixture and bypass screws back to their base settings and the engine will happily tickover at about 750rpm now with a much steadier rythm to it. It's took a while to get there but with your help and advice I've learnt a few things along the way too. Wouldn't life be boring if everything worked perfectly first time?
So now it's ready to go to the rollers and see what it's got. From the spec below, what would be a reasonable power figure to aim for? Presuming I've done a decent job on the head.

84.6mm pistons
STD Monte cams
9.3:1 CR
DIY ported 'volumex' head with 43.5mm inlets
42 DCNFs, 36mm chokes on Alquati manifold
Ansa 4-2-1 manifold with straight through silencer (180 airs, 140 mains at present)
Electronic ignition in STD distributor
Monte g'box casing with Volumex internals
Delta HF Turbo clutch

If it makes what it should on the std cams then the plan is to upgrade them once the budget allows. I've already got vernier pulleys on there to dial in the STD cams.

Thanks again,
Nick

[Guy Croft]

Well done Nick!

I love it when a plan comes together!

I'd be a bit concerned about the 36mm chokes in 42mm DCNFs, would use 34mm myself. I would be looking for something on the right side of 138bhp @ 6000 rpm (at least 113 at wheels) there with a lovely strong torque curve, pulling easily from under 1800 rpm peaking with about 138lbf ft - or more - at about 3800.

Do make sure you are now getting full throttle!

GC

[nickp]

The chokes were machined by a friend. The original plan was to have some 'hot' cams in there from the start so I told him to do them to 35-36mm. Then the cams didn't arrive but I couldn't get in touch with him in time to tell him to do them to 34mm. If it is a problem then I've got another small set I can have machined.
I'll let you know how I get on at the rollers. I might wait until the spring, as it's a bit late in the 'season' now.

Thanks again,
Nick

[Guy Croft]

OK - try the chokes and see how she behaves, if the bottom end to mid range isn't brilliant get smaller ones,

G