Lancia Motor Club

Model Technical and Interest => Fulvia => Topic started by: lancialulu on 22 June, 2020, 08:26:06 AM



Title: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 22 June, 2020, 08:26:06 AM
Well one of the jobs almost ticked off during lock-down is fitting a pair of 45 DHLA Dellortos to my 1600HF.

A bit of background. I restored my 1600HF in 2006 in time to go to Turin for the centeneary. My engine is non-standard, with a big valve ported head, Holbay cams, CPS 11.1 CR Pistons, and group 4 exhaust manifold. I also run an oil cooler and luminition ignition. As some may know I am a fan of the Solex 42's when properly set up, and these match the engine quite well.

As this is our "fun" Lancia I always thought a larger set of carbs would be an interesting experiment. I had acquired a pair of 45 DHLA's some 10 years ago off ebay ostensibly previously fitted to 2000 Pinto Ford. I cleaned them, noted the jetting etc and put them on the list of jobs for this car.

Just before lockdown I was lucky enough to find (at a cost) an unused works manifold for these carbs, so finally I could get round to the project to fit them.

First was to get the carbs in the right ball park re jetting etc. Asking around I ended up with:
Chokes 38, Main Jets 158, Idle jet 60, Emulsion tube 7772.6, Air correction jet 170, 10g floats set at 17mm from top of float lid (inc gasket), viton tipped needle valves
I would be very interested in anyone with 45 DHLA's fitted to their 1600 Fulvia who can share the specification and experiences
I got these parts from https://carburatori-italia.it/en/

The manifold actually turned out not to be plug and play needing all the engine side mounting holes relieved to allow nuts to go on with a minimal spanner clearance (1/12turn at a time), and even then I had to resort to using 12AF/M8 nuts on the underside as there was no room for 13 mm. I also had to port match on the engine side as my cylinder head had been ported. On the carb side everything lined up - unlike some of the manifolds out there. Next was to create clearance for the throttle lever and also the distributor, and re-route the servo vacuum pipe.

I intended to use "Misab" carb joints and "cosworth" and Thakwray flexi washers so need to make up a carb support plate and strap (to one of the engine mount bolts).

One of the biggest challenges was the alternator. I wanted to retain the OEM Ducellier if at all possible. I filed the slot deeper on the adjuster bracket and found after a bit of trial and error a 740x10 v belt gave me the ability to set the alternator below the front carb (a 735 belt was too short and 750 belt loo long).

I needed to reroute the fuel pipes and make a fuel return from an old solex part, set the fuel pressure to 3psi, and move the radiator as far forward as it would go (which entailed making a shorter top strap). The throttle/balance connection was another story as I could only deduce I had to make something as standard parts were made for an Alfa throttle system not a Fulvia.

On first switch on (no cranking) the fuel pump (silver top FACET with Filter King regulator filter) continued to pump fuel and this poured out of all 4 carb venturi. A bit of a panic..... and a bit of head scratching. I had originally set the float level to 14mm on advice of of the Italian Carb company. I did know the 10 gm floats are supposed to be et at 17mm from online sources so I whipped off the floats and reset their heights to 17mm and this time no fuel poured out.

Amazingly (without choke - still to be fitted if I need too) the engine fired and soon I was able to get a smooth idle of c900rpm. I have yet to drive it and there may be a flat spot on initial wide open throttle due to the large choke sizes, but it was always going to be compromises.

Oh I should say this manifold gives me c 7mm clearance from the top of the brass carb choke nut and the bonnet underside,

Any yes this pic is before I fit ram socks for road use.





Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: Neil on 22 June, 2020, 09:33:37 AM
Well done Tim, you are getting on well with this I see, I have bought parts from my DHLB35s in the UK, had good service from http://www.dellorto.com/, I also fitted return to my carbs, they stocked the original parts if you need to get one.


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 22 June, 2020, 04:20:51 PM
http://www.dellorto.com/, I also fitted return to my carbs, they stocked the original parts if you need to get one.
They are good and have extensive stock - same as Italian firm but if buying a few items it make sense to order from Italy. BTW I wanted that fuel return union but it is currently unavailable, hence the Solex addition....


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: DavidLaver on 22 June, 2020, 09:48:51 PM

A good challenge !!!


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 24 June, 2020, 04:35:52 PM
Well this is now all fettled. Float levels correct to 27mm depth of fuel with top of float chamber removed. Fuel pressure set to 3psi, and fully road tested. RamAir filters finishes it off.

This is a good upgrade with minimal stumble compared to the narrower 42's and linear power delivery.


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: Jay on 25 June, 2020, 01:08:52 PM
looks good, very tight plus a pre-warmed source of intake air.


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 25 June, 2020, 02:04:18 PM
looks good, very tight plus a pre-warmed source of intake air.
When I get round to it I will adapt the support plate to become an air box pulling air from within the inner wing, but at the moment I cannot feel the need as it runs great.


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: Charles Frodsham on 03 July, 2020, 04:09:38 PM
Hi Tim

How do you rate the 45ís compared to the Solex 42? Any plans to check power increase on a rolling road?

Charles


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 03 July, 2020, 05:22:14 PM
Hi Tim

How do you rate the 45’s compared to the Solex 42? Any plans to check power increase on a rolling road?

Charles
Charles it is quite a revelation and not expected. They are smoother in delivery than the 42's and don't stumble at the Achilles heel of the 1600/42 Solex with many stumbling at 1800-2300 rpm on large throttle demand. I was lucky I guess to get a part choke/jetting setting and use the remained of the jets /emulsion tubes that came with the car (it was previously used on a grass tracker Ford Pinto mill on 36mm chokes. I have upped these to 38mm (2mm increase on 42 Solex) and a larger main jet. Logic suggests this will not work but it does.

I am still fiddling around with float levels and fuel pressure, but it starts easily (easier than the Solex's) and holds a steady 900rpm tick-over. No plans to go on a rolling road yet I will look at that in due course should I feel I can get significant improvement I have yet to colourtune and gas analyse, but suspect from the right foot feeling and the not overly rich exhaust colour it is there or there abouts. My engine is at a state of tune that has benefited from this upgrade. I doubt it would be the same on a standard high mileage unit.

BTW anyone know of a competent rolling road that has dellorto experience (and a range of jets etc) south of Watford Gap?


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: Jai Sharma on 03 July, 2020, 07:37:56 PM
Rallytec in Boreham might be worth a look though not sure about their Dellorto spares


Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: Charles Frodsham on 03 July, 2020, 07:57:10 PM
Tim. I wonder if itís down to the Dellorto being an intrinsically better carb....less prone to wear on the spindles/chokes?



Title: Re: Fulvia 1600 gets 45 Dellorto treatment
Post by: lancialulu on 03 July, 2020, 09:05:56 PM
Tim. I wonder if itís down to the Dellorto being an intrinsically better carb....less prone to wear on the spindles/chokes?

Donít know. I rate the Solexís regardless.