Stromberg question

[TurboFource]

The needle in one of my slides seems to be spring loaded as it will pull slightly from the slide and then go back in, you can also twist it freely in the slide. My other slide the needle doesn't seem to be spring loaded and you can't twist it with your fingers. Which one is correct? How do you get the needle out of the slide? I would rather ask than mess something up....

[LotusJoe]

[SENC]

If you haven't found it, yet, the Buckeye Triumph site has a fantastic series of pages on the Strombergs.  The snippet below from that should help with your specific question, but worth a read.  I rebuilt a set for my Elan a couple years ago and have several spare bits so can grab pictures of anything "internal" should you need.  Also, the burlens site is quite valuable.

https://www.buckeyetriumphs.org/carburetors

[jbcollier]

The Stromberg needle comes in a holder (as shown in SENC's photo).  If it is a fixed needle, then there is a screw on the side that holds it in place.  The needle holder has a corresponding flat spot for the retaining screw to bear upon.  If it is an adjustable needle, it's a bit more complicated.  The screw on the side is a guide pin that fits in a slot cut in the holder.  In order to remove the needle, you first use a special tool down the damper tube and turn the adjuster until the holder sticks out the bottom. Now remove the guide screw, hold the needle holder and turn the adjuster until the needle holder is free.

Lotus TCs never came with adjustable needles but it is a better way to go.  You can get the pistons for adjustable needles from a TR6 or TR7.  Then order replacement UK spec needles and swap them into the adjustable needle holders.  I would also change the needle jets at the same time.

More info here:

http://www.lotuseuropa.org/LotusForum/index.php?topic=3619.msg37946#msg37946

[TurboFource]

Thanks JB!

[TurboFource]

Are there different size "jets" available or is all fuel metering requirements handled by changing to a different needle with a different taper?

[jbcollier]

The needle jets do not come in a range of sizes.

[SENC]

But be aware that jets do wear from needle contact over time - and depth of jet impacts air/fuel mixture, just as raising/lowering the needles.  There is a Lotus Service Bulletin describing correct depth.

[Roger]

The Lotus Elan S4, non-Federal, had adjustable needles and different carburetter adapter blocks, connected by a balance pipe. This is the setup to get, if you can.
Apart from a Weber head, that is....

[literarymadness]

My Early TCS 2758R came with Stromberg Carbs and adjustable needles. I know a couple of guys with Fed-spec Sprint Elans with Strombergs and and they have adjustable needles. I was under the impression that the only Fed-spec Twin Cams with Strombergs that had fixed needles were the Fed-spec Elan S4s. That all Big Valve Stromberg versions had adjustable needles and that the early non-Big Valves TC Strombergs had fixed needles. The Twin Cam supplement mentions only fixed needles but doesn't reference the Big Valve. 

[literarymadness]

I stand corrected Fed-spec Europa TC and TCS's with adjustable needles like mine are retrofits. My Carbs are the original. Just didn't know that they were modified. Sorry to question you JB

[jbcollier]

Eh?  Question a way.  We all learn that way.  I can assure you that I make mistakes and have been mistaken many a time.

Adjustable needles with the Euro spec profile makes  for a sweet set-up.

[TurboFource]

I have read you can modify the stock air valve/slide/piston to accept the adjustable needles.
If I can't find Triumph ones I will give it a try.

[SENC]

Turbo - I'm fairly certain I have a spare piston/air valve for fixed needles in my spares box if you decide to modify and want 1 to experiment with.  Just pm me when you get to that point.

[TurboFource]

Thank you SENC!