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Starting point for Carb needle

Posted: Tue Sep 20, 2022 11:56 pm
by moggiegeek
As the magic day of finally putting in new build engine arrives I'm needing a starting point for suitable needle/s
Engine spec is:
1275 pre A+, balanced. Minisport stage 3 head, Maniflow exhaust and inlet manifold, Kent 266 cam, HIF38 with K+N filter.
I'm using the HIF38 as I know it works! I also have HIF44.
Where should I start with needles?
There was an on line chark/resource I had at one time but it seems to have got deleted.
All help gratefully received.

Re: Starting point for Carb needle

Posted: Wed Sep 21, 2022 6:09 am
by Sleeper

Re: Starting point for Carb needle

Posted: Wed Sep 21, 2022 7:10 am
by oliver90owner
You may get away with playing with needle profiles with s single carb, but I reckon it needs rolling road checks to optimise any highly tuned engine.

Back in the 1970s, when we played with Fords, I never thought the relatively lowly DCD 28/36 was set up optimally for our modified engines (even more-so, with twin DCEO 40 carbs fitted).

I didn’t run long on the twin carbs as things were getting too expensive at the time (and I planned to emigrate, so sold off some of my kit). These days, I would invest in a mapped ignition timing set-up and a professional tune on a dynamometer if I were to fit substantially modified engine parts. Pay-back on fuel cost and improved power delivery is likely quite reasonable.

Re: Starting point for Carb needle

Posted: Wed Sep 21, 2022 11:15 am
by moggiegeek
Thank you both. In due course I would want to have a rolling road session when the engine is run in.
My current challenge is to start it up and run it in.
I saw Minty Lamb but wasn't sure how to use it, for an HIF38 it only seemed to be offering one needle AEM from memory.
Looking at the general spec of the engine does anyone have any educated guesses?
Thank you

Re: Starting point for Carb needle

Posted: Sat Oct 01, 2022 7:50 pm
by moggiegeek
After some research I thought I'd pass on the consensus for starting point for my engine as above.
Running a HIF44 - which was also recommended the starting point was BCE - CUD1152
Running a HIF38 - ABD - CUD 1027 was recomended.
Other suggestions were to opt for a slightly leaner needle for running in to prevent the fuel washing away cylinder lubrication.
Hope this info helps someone - we'll see what happens in due course.