I need help with triple-choke Webers!

[a310man]

Hi 911 forum

I am new to the forum and, although not a 911 owner, have a question about triple-choke Webers.

One of my cars is an Alpine-Renault A310 V6 (website Alpine-Renault A310). I have rebuilt the car into a replica of the A310 that competed at Le Mans in 1977.

At present, I am running a Dutch Youngtimer Challenge engine, which means the capacity must remain standard at 2664cc. However, it has modified, pocketted Mahle pistons and race cams. To feed the go-juice, it is currently fitted with a triple Weber 42DCNF setup and runs well on this arrangement.

However, as I continue development, I have bought a pair of triple-choke Webers with 40IT 100 stamped one one of them. They came as a second-hand pair from the same car (911), plus repair kits with gaskets, 'O' rings, copper rings and float valves. I also have a carb manual, but the tops of the carbs are different from the carbs shown in the manual and different from most other triple-chokes I have seen in that there is only one fuel inlet on the carb top. The floats are suspended from the carb top, rather than 'floating' in the float chambers. I hope I have managed to add pics. Where can I buy float valves that fit in the underside of the carb top? And what car where these carbs originally intended for? They were sold as from a 911, but which one I do not know. HELP!!

[a310man]

Here is the engine with its 3 x Weber 42DCNF carbs. It is good for just over 200hp.

And here is the car itself.

[Quickstep192]

Try PMO at PMO High Performance Porsche 911 Carburetors & EFI & MFI Fuel Injection Kits

I find it best to fax them a letter with what you need. Include your phone number so they can reach you.

[Quickstep192]

Oh, one more thing......

If they're like the 40IDAs I have, you'll also need shims (washers) to adjust the float level when you replace the valves.

[Steve@Rennsport]

Love your A310,...

Wow,..in all my years, I've never seen any Weber triple IDA/IDT's in that configuration. Might those possibly be the Lamborghini version of that carburetor? Triple Webers were used on the Miuria and Ferrari 512 BB, as I recall.

Those floats adjust like a PMO or any other normal carb; by bending the tang on the floats to suit. The specs are in the Weber manuals or the Haynes version. Without seeing the float needles, I cannot tell you if they are standard ones or not.

[a310man]

Hi again chaps

Thanks for the information. I had only seen a couple of pics of the carbs when I bought them and it wasn't until I was ready to rebuild them that I noticed the odd arrangement for the fuel inlets and the float locations. There are no float needle valves fitted - just the holders. Those are the bits I need. Here is a pic of one carb showing the lack of float valves and the float fixing.


Oh - the engine is rear-mounted like the Porsche 911. Hung out in the breeze way behind the rear axle line. Handles somewhat sweeter than a similar vintage 911 though and it is nice owning three of these very different French coupes.

[a310man]

Thanks to Quickstep192 and Steve@Rennsport for the replies. I have contacted a German link from the PMO website and will update you as soon as I have discovered more about these carbs.

What a superb forum!