SAH manifold

[mark powell]

I'm not a carburettor geek, but some years ago I was offered a SAH inlet manifold with twin Stromberg CD150's.  I believe that this was an option for the 1300 engine, but I don't know if that was the Spitfire or Herald.  Anyway, nothing venture, nothing gain, I fitted them to the 1500 Spitfire engine that was in my Herald estate at the time. (now in The Heep). I had no real running issues, apart from being a bit thirsty, but I've always wondered if different needles would be of benefit for the larger engine.

 I pulled a needle this morning, 7B, which I cross referenced on the net to be the standard needle for the later 1600 Vitesse...  So, do I leave it all alone, knowing that my yearly mileage will be fairly minimal, or should I revert to a pair of standard SU's?

 Either way, the Strombergs will have to come off for a service...  ( a rebuild kit from Burlen will be about £100 for the pair,  Used pairs of SU's  at least twice that on 'the bay')

 Decisions, decisions... 

[dougbgt6]

Mark,

Stromberg's don't have a large range of needles, for mine, CD150SE's, early, late and pancake air filter. Don't know about yours though.

£100 for a rebuild kit sounds a bit steep, many of these kits have everything for every variant and you wind up with half the kit left over. Better off finding exactly the individual bits you need and order separately.

Doug 

[Clive]

I think John Kipping played about with strombergs on engines, and he used 1500's a lot on his fleet. 

Plan B. Get a dolomite 1300 single SU inlet manifold and an SU 1 3/4" carb. Simpler but plenty of go..... or even a single HS4. Very little power difference, and a single carb is so much less grief.... (if you want a 1 3/4" SU I have one here)

[mark powell]

That's another thought.  Thanks Clive, I'd forgotten about that set up. 

[Pete Lewis]

some idea the 1500 and 1600 have some similar air volume flows ?  but whilst you may have 7B needles the 1600 did not have a piston damper spring but a thicker heavy diaphragm clamping disc , 

if you have a spring you may improve the richness  'off idle'  by removing it    certainly a 1600 with spring is very rich mid range

Pete

[mark powell]

Thanks Pete,  yes, I noticed that the 1600 doesn't have damper springs, so I shall try without. 

[Pete Lewis]

In general  all needles su and stroms have the first two stages of taper the same so idle setting doesnt mean running is in harmony

Explains why you can have a nice  idle mixture but open the taps and it all goes wrong as the piston raises the needle to a moddle profile

on the taper 

 

Pete