Lancia Beta Forum

Technical stuff => Fuel System Carb => Topic started by: skattrd on September 09, 2014, 05:55:12 PM



Title: Installing twin 40's
Post by: skattrd on September 09, 2014, 05:55:12 PM
I won the auction for some twin Delorto 40's & GC manifold from ebay, link (http://www.ebay.co.uk/itm/Fiat-Lancia-Twin-40-039-s-Weber-dellorto-on-guy-croft-manifold-/141392651291?ssPageName=STRK%3AMEWAX%3AIT&_trksid=p2047675.l2557&nma=true&si=ZEislbNxOEHEycEtrHdHXdycK4E%253D&orig_cvip=true&rt=nc). From the description they should be correctly jetted for my 2000 Spyder.
I was planning on fitting an electric pump & regulator but have just come back from the garage where I had a chat with my brother-in-law (mechanic). He suggested that the standard mechanical fuel pump may be fine with twin 40's and they'd be worth fitting them as they are to check to see if they need a rebuild or re-jetting.

Thought/comments, would the twin carbs be ok with the standard mechanical pump or is that dangerous/risky?


Title: Re: Installing twin 40's
Post by: HFStuart on September 09, 2014, 06:58:52 PM
Looking at the auction there's a good chance the engine will run without rejetting the carbs  - whether it runs well or not you'll only find out by trying. Also the ignition may need adjusting to suit the carbs. The only sure way to set them up properly is on a rolling road.

Regarding the pump 40s are designed to run with in a given pressure range - the beta pump is unregulated as in standard set-up the fuel circulates through the return line back to the tank. If you plumbed it in to a blind end you'd probably flood the carbs. You could try it with the mechanical pump and a pressure regulator. Ideally you still want to divert surplus fuel to the return line - it will help prevent vapour lock in the fuel lines.

For fast road use (say up to 130bhp) the standard pump has sufficient capacity if it's working well. Again you should get this checked at the rolling road - if it runs too lean on full throttle at high rpm you're in trouble.


Title: Re: Installing twin 40's
Post by: rossocorsa on September 10, 2014, 08:32:02 AM
Electric pump is usually a better soution on betas and it also means you can then do the auxilary shaft lobe mod that adds to peace of mind on a 2 litre car. Be careful with tuning it can turn into bottomless pit.