Race Engine Forum UK

hi all!

i've post this on a few forum, but nobody can answer...my LMC no has twin 42dcnf, lighted flyweel, balenced shaft, pistons...CSC exhaust, well the minimum for a montecarlo!
problem is i'm not so satisfied about power and torque improvement.of course, i did not expect my car to become a RED one, but i think engine is not working as it should.
it suffers from throtle "hole" (still uses standard electric fuel pump at 0.4 bar of pressure, maybe not enought?)and engine achived maximum RPM too fast (flywheel is about 7.3 kgs)
i think jetting are not good for my engine, even if i did it with the help of a data sheet made to now how to jett...
help!
antoio

OK

I don't know the full spec but with 2 liter TC on pair 42dcnf - this should get you close:

chokes anything from 34/35/36, I would not go smaller than 34mm
main jet 130/135 (I mean 130 or 135, whichever works best)
Air corrector 170/175
Emulsion tube F21
idle jet 45/50
pump jet 45/50

If it's gasflowed/billet cams go towards the richer mains (bigger) and richer air correctors (smaller).

Ignition timing 10deg at 750-900 rpm, 34 deg total advance (idle or static plus centrifugal) at around 5500. Carb idle mixture and balancing is imperative for good results, make sure you are getting full throttle with pedal fully depressed.

Weber UK have a marvellous helpful site, if you want to learn about the parts and operation of racing carbs go here:

http://www.webcon.co.uk/weber/40dcoe.htm

GC

[quote="Guy Croft"]If it's gasflowed/billet cams go towards the richer mains (bigger) and richer air correctors (smaller)

does it means cams that open valves more than stock?

i 've checked my jetting, i understand why engine was not so good

main is 145
air is 210
main is 145
emulsion is F39
idle jet is 60
chock is good, 36
i'll try to buy this parts somewhere.

pedal fully depressed gives full throttle.i'll go back to my local garage and ask for a new ignition timing.
antonio

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