DCNF 42 jets for Lancia Beta 2.0 ltr with standar cams

[cheitane2003]

Hello Guy:
Please,let me know wich should be your deicision about jetting my Lancia Beta 1919 cc with two Weber DCNF 42 with:
- Ported head
- Standar valves
- Lightened flywheel to 5,6 kg
- CR: 10-10,5
- Cams with true lift 10,8mm (I can not measure timming whit precision and there are no marks on them).
Now the carbs are fitted with:
Difusor: 36
Emulsion tube : F22
Main jet: 140
Air corrector: 200
Idle jet: 60
Acceration pump: 50
Auxiliar venturi: 3,5

I send an image of the cams in case you can recognize them or you know something about its time,I think they aren‚´t very radical because I got a very low and regular tick over.
Thank you very much.
Yours faithfully,

[Guy Croft]

That cam bears all the hallmarks of being a regrind of an OE cam, where the cast surface has been cleaned up to make them look, er 'more like a competition cam'. If I am right then the torque from them and bhp too will be disappointing.

As for jetting:

Diffusor: 36 do you mean secondary choke? if so I would not use 36mm on 42 DCNF with reprofiled cams. Actually I would never use 8V reprofiled cams but if you do keep them go down to 34 chokes or your torque is going to be very poor.

Emulsion tube : F22 OK
Main jet: 140 You might need 145
Air corrector: 200 I'd come down to 185
Idle jet: 60 Bit big really, 45 should be big enough
Acceration pump: 50 OK
Auxiliar venturi: 3,5 You never change this anyway.

Really you are wasting your time trying to optimise an engine when you don't even know what the cams are. And I'm guessing at the right jetting too. The cams are simply one of the most critical power producing components in the whole motor.


GC

[cheitane2003]

Hello Guy:
Thank you very much for your help.
I still have the original Beta cams with 13-45-49-9 and a lower TL of 10.4mm, but as I can see,the noses are sharfer than in the cams on the photo,so I supose the ones I installed have bigger overlap, that‚´s the reason of them precense in my motor.
So,al this point,do you recommend my to install the original ones again in the car with the carbs nummber you gave me?
I forgot to say the motor has a CSC 4-2-1 exhaust manifold.

[Guy Croft]

You've got two choices really in my experience anyhow.

1. Use std cams and restore the great torque characteristic they give with power peaking at about 6000rpm.
2. Use new billet competition cams, either a pair or just an inlet comp cam with std ex, this works very well for fast road. But the only firm who makes them with distributor drive gear on inlet is the Italian firm Colombo and Bariani. I am an agent for them but it could be a long wait for them as they do not stock the type with gear any more.

Because of the complexity of fitting and timing with comp cams etc - I'd be for going back to the OE cams.

GC

[cheitane2003]

Many thanks Guy!!!

[cheitane2003]

Hello Guy:
On the cams you can read CB-04 and CE-04.
The numbers in the shaft are: Fiat 335582 and 553382 but aren‚´t clear.
Do you know something about them?They are the cams of the previous photo.
Thank you very much.

[Guy Croft]

Regrinds, get rid of them.

GC

[cheitane2003]

Many thanks Guy.
At this point I can finish a bad story...