International Lancia Forums

sounds more like a flat spot??? But I had fitted 35mm dellortos from a 1.6 Zagato which went fine to my 1.6HF for the Turin trip (to save fuel???? well went from 24mpg to 28 so did!). Trouble was they were fine to 80-85 mph then no performance at all - they were just undersized. Back to the 42's and no problem.

Tim

Hi Tim,

I will be very glad if you could send to me the details of the tool to measure the float level.

Thank you in advance,

Carlos

Carbs off, all jets and emulsion tubes replaced with those from the other carbs. All the calibration numbers were the same but the washers were missing from under the heads of one carb's emulsion tubes. That might make a difference as the holes in the tubes would be at a lower level.

Washers reinstated, floats with the lower level, as installed by the carb rebuilder, also reinstated. Refitted, resynchronised, idle mixtures reset. Out on the road and yes, maybe better with a bit more bite at high revs but still not as effortlessly smooth as before.

Then today, a brainwave. It has been very cold here in England these last few days, with frost most mornings. Carburettor icing? Is that not why there's a winter setting on the air filter spout, which draws air from around the exhaust manifold via a convoluted tube? So I set the spout's flap to winter mode and have just been out for a run. Above the fizz of the body dissolving in the road salt (not really, there's loads of Waxoyl under there) I could feel and hear a happier engine. I think it has regained its former energy and accelerates cleanly to 6000rpm if perhaps a touch less smoothly than before. That could just be the surrounding coldness and the reduced resilience of engine and subframe mounts, though.

Anyway, it seems the hot-air tube is worth keeping although I have heard that some people throw it away. But then they might not drive in near-zero temperatures.

Tim very kindly sent me the dimensions for the tool to set the float correctly, so I'll make one when I get a chance and see if any of my floats are anywhere near correct. Meanwhile, I think I've cracked it. The idle has just crept up to 1200rpm, though. Which is heading towards where we came in...

John Simister

John

I dont use the hot air tube. What made the change for me was timing the cams accurately. Now the car is transformed.

Tim

For many years I have indeed driven without the hot air hose from exhaust to air filter box. However, some weeks ago I reinstalled it on Tina, one of my 1967 coupe rallye 1.3 Fulvia's. Tina is now in for some work such as subframe drop for a repeat waxoyl job and solving some oil leaks on rear crankshaft seal and gearbox.. This week I am driving around in Elena my other 1967 rallye 1.3.She does not have the hot air hose but does run smoothly. The weather is cold but the air is dry. The get ice one needs sub zero temperature and water. When the temp drops significantly below zero there is not enough moisture in the air to get ice. It is indeed as you say around zero (degrees C of course) or just above are the temperatures which are most likely to cause ice. Evaporation of the petrol reduces the temperature by a few degrees.

The worst situation occurs at a few degrees above zero when closing the throttle after a high power run. The fuel evaporating during the high speed run will cool down the carburetors. Ice will not form because of the high air flow but will form when the throttle is suddenly closed and the airflow is reduced.

Note that the rather small summer - winter flap does close the hot air inlet when in summer position but it does not close the main inlet even by half when in the winter position.

I have experienced icing a number of times (mainly in old ford cortinas in a past life) and the effect is dramatic. The car effectively dies as the ice round the central fule delivery shuts off the fuel. 10 minutes on the hard shoulder and the ice melts and drops into the plenum and one is on ones way again!

Tim