Mrfred 30 Report post Posted January 14, 2017 Hi All, I though I would start posting abut my latest upgrade to my 1965 Hillman Super Minx. A few months ago I bought 2 Weber IDF 40 down drought carburetors to fit. I know it will never be a speed daemon but I just like building things. Carb's are new to me as I mostly work on injected engines so this was bit of a learning curve (still is). I will add some more posts of the build when I get more time. Here is a photo of the carbs when they arrived 5 Quote Share this post Link to post Share on other sites
Mrfred 30 Report post Posted January 14, 2017 As this engine has the intake and exhaust manifolds in one flange I have to build the Intake and exhaust at the same time. Using Solidworks I sketched up the flanges and got them laser cut out of 10mm mild steel. Shopping around I found that Stainless Design was pretty good on price and and had good service (also have a work account with them). I started looking around for Extractor calculations to get the right size pipe diameters and primary lengths. I found it hard to find a reliable formula as some of the sizes seemed too small or too long. In the end after talking to a few people I just went with best guess. My first design was 4-1 style extractors but after reading a few forms and doing some research I settled on a 4-2-1 design. Lucky there is quite a bit of room in my engine bay. In the end the Intake is 38mm, Exhaust is 32mm Diameter for the first 315mm then 40mm after the join with a total length of 1100mm finishing with a 50mm section 9 Quote Share this post Link to post Share on other sites
Mrfred 30 Report post Posted January 16, 2017 Built up the rest of the manifold. It was a little rough (ie not grinding down all the welds) as I planed to heat wrap (not sure any more though) Once Installed I had to build the synchronization link between the 2 carbs and run new fuel lines plus accelerator linkage. I decided to work late to get it all done. Finally finished it at about midnight and thought I would lake it out for the first run. Everything was going well until I pulled out on the the main road and the accelerator pedal fell to the floor. Luckily the idle was high and I managed to ride the clutch until I got off the road. Turns out I didn't put a split pin in the accelerator linkage and it was lying on the ground. After some tweaking I was good to go again. Definitely more power and acceleration. Hopefully I'll post a video of it running soon. 6 Quote Share this post Link to post Share on other sites
