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Title: What can I get out of a pair of Dellorto 40s Post by: Chris bugster on June 17, 2011, 11:33:12 am I need some help with advice on an engine build.
The spec is 1914cc Scat Wedge ports 44x38mm 40mm Dellortos I mainly want to know what cam would be best in this combo that is probably limited by carb size. I think the largest size vent I can use is a 36mm. It's going in a very light car (700 kg with driver) with tight gears. I was thinking about an FK10, but wanted to hear from you guys. Is the cam too big? I would like to get something between 150 and 160 hp. Title: Re: What can I get out of a pair of Dellorto 40s Post by: warp on June 17, 2011, 20:29:28 pm Your valve size and carb size does not match very well.
You need a lot of cam for those big heads but the carbs will probably limit the performance of the engine. Title: Re: What can I get out of a pair of Dellorto 40s Post by: Fasterbrit on June 18, 2011, 08:57:37 am Ditto what Warp says. You will struggle to go past 145 bhp on 40's. You really need bigger carbs to make those heads work.
Title: Re: What can I get out of a pair of Dellorto 40s Post by: Chris bugster on June 18, 2011, 13:02:00 pm I know you're right fellas, but thought I might get away with it. I guess I'll have to run the 1914 with a C45 and 1.25s and a set of 40x35 heads that I openened up the intake ports to 35mm on and staightened out the exhaust on. Just need to finish the chambers, fit seats, guides and they'll be good to go. I know this combo works, so I'll stick with it.
Title: Re: What can I get out of a pair of Dellorto 40s Post by: Chris bugster on June 23, 2011, 11:04:42 am After reading another topic regarding cam choice and the answers posted by two very respected European tuners, I have decided to use those big heads. I also remember, digging deep into my memory, a 1914 we had on the rolling road about 16 years back, that ran a pair of 40s made almost 160 hp with an Engle 130(?) some nice heads and about 10.5 to 1 squeeze.
Title: Re: What can I get out of a pair of Dellorto 40s Post by: AntLockyer on June 23, 2011, 11:24:02 am My 1914 had pretty big vents in, I believe some machining took place to fit them. I'll see if I can find them later. It ran 13s with a 130 cam, full steel 67 with stock box.
Title: Re: What can I get out of a pair of Dellorto 40s Post by: Lids on June 27, 2011, 18:36:47 pm my 1914 had 44 x 37 heads by JC @ stateside with a 120 and twin del 40's. Took a while to spin up, but once it did :)
Title: Re: What can I get out of a pair of Dellorto 40s Post by: Chris bugster on June 27, 2011, 19:17:52 pm Lids- Could you be more specific as to the 1914 engine you had? Where did it start to wake up, where did it stop pulling and did you ever get it on a dyno?
I know JC's work as I used to work for him about 14 years back. Title: Re: What can I get out of a pair of Dellorto 40s Post by: Lids on June 27, 2011, 20:30:40 pm I know, you were there when i bought the heads. You took me out to listen to the sound of your straight cuts in a yellow bug. round about 98.
Came alive at about 2.5-3k never span it more than 6k as i was using stock crank, but it had more to come. I frightened the life out of my wife, we pulled out of Sainsburys on the A10, i floored it and all i could see were sparks out of my rear view mirror (it was night), the exhaust rubbing on the tarmac as the front lifted and the rear squatted. Title: Re: What can I get out of a pair of Dellorto 40s Post by: Torben Alstrup on June 29, 2011, 22:46:36 pm Wedge ports on a 1914 is too much, unless you want to make max power at 8000 rpm. The 40 Dells wohnt follow that high, so the combo is a mismatch, which will never perform well due to the airflow never being right...
If you have the C45 cam, use it along with the set with 40/35 mm valves, and add 1,4 rockers. and 9.5 - 10 - CR. If the heads are good, and the exhaust matches, you can pull 150 very usable hp with the Dells. (Even on 2275īs I often REDUCE port size, and make more power, as long as we are not talking 310+ degree cams) T |