Post Hibernation issues...SUs

[Baz]

AHA!!!
Have an idea.....
Will my float chambers from the HS4's from the B work?
If not, will HS4's work on the 1275 with the HS2 linkage?
I was going to put the 4's on fleabay, but.....

 

[regularman]

I was definitely talking DGV.

 

[Baz]

Or, the guru says he has a set of McCooneys (SP) and a manifold from a 1275 BE he used to race......

 

[Dave Russell]

Turns out, I'm pretty sure my floats are off, had a local guru look at them tonight and they're just flopping over because of the Grosse jets.
$350 for rebuilds.
Now I'm ready to buy a weber. Trade anyone?

From your description, the Grosse jets are causing the float level to be too high. These jets are often the cause of more carb problems than they cure. Partly because it is so easy to get one that has the wrong installed height & is hard to set the float level correctly for your particular carb. Partly because their design is not as brilliant as it seems.

You can get the original type inlet seat & needle assembly from Moss for about $13 per carb. SU HS2 or HS4, part #373-625 for either carb. There are thousands of cars running around with the stock type float inlet needles & seats. Few of them have problems due to the design.

The chances are very good that you could cure the problem with nothing more than new original type needles & seats. If you just want to spend a wad on having the carbs rebuilt or changing to a different type, that is a whole nother matter.
D

 

[Bugeye58]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Dave Russell: From your description, the Grosse jets are causing the float level to be too high. These jets are often the cause of more carb problems than they cure.
[/QUOTE]

Hence my original comment about "Gross Jets".
BTDT
Jeff

 

[Baz]

You can get the original type inlet seat & needle assembly from Moss for about $13 per carb.

I looked at the 4's last night, sure enough, needle and seat, same size, and they're level so yes, I'll get those transplanted this evening just to see if that is my problem for sure and I'll likely invest that way, Thanks Dave.
I love how the 'usual suspects' advertise Grosse Jets!

 

[Hap Waldrop]

Get needles and seat form Joe Curto https://www.joecurto.com they are viton tipped and the very best one available, I buy all my carb parts from Curto, and wouldn't even dream of getting them from a catch-all company. The good thing about Curto is he's built more carbs than most of us have ever seen, so he know what the heck he's talking about. Oh and throw those grose jets in the garbage can, unless they 20 year old NOS, they are junk.

And yes, float bowls from HS4s and HS2s are interchangable. Little secret for ya, put a extra flat washer behind the rubber and brass washer on the flaot bowl bolt, this will keep them from being wobbly.

 

[Baz]

/bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif E-mail sent.....
..vroom post imminent. /bcforum/images/%%GRAEMLIN_URL%%/driving.gif

 

[jlaird]

As the local SU guru, ah hum. There are not a lot of things that can be wrong with SU's The real problem starts when all the things are wrong at the same time.

Start with air leaks. If too rich that's prob whrere your prob lies. Intake gaskets and throttle rod bushings, should be no wiggle.

Joe will redo shafts for under 100 bucks the pair and let me tell you they are smooth and close tolarance fit.


As an aside let me say here that it only took me a month to get mine sorted out.

 

[Baz]

Joe got me sorted.
The curiousity did get to me, I placed the HS4's up against the manifold and it looks like they'll fit, not sure about clearance to the bonnet though.
Another time perhaps, sounds too scary right now.

 

[DrEntropy]

The Viton tip needle/seat Hap referred to from Joe are as good as a "lifetime purchase" can get. The things are awesome. And only ONE SET of "Gross Jets" has ever worked right for me. I suspect Hap hit it: they were "originals".

 

[Bugeye58]

Barry, to run the B carbs on the Spridget you will have to shorten the B manifold to match the port spacing on the A series head. That's what we do to run HS4's in the production classes, where allowed.
No big deal if you're handy with the TIG welder.
Jeff

 

[Hap Waldrop]

Twin HS4s on a street 1275 will be too much carb, but you should get them to work by using much leaner needles. You can make adapter HS4 to work with the 1275 intake, but the better path is as Jeff mentioned with the shortened MGB intake. Personally I think this is the wrong path for a street 1275, I think using the early manifold and the early HS2s to be a better set up for the street, more than enough carb for streeet engine, no matter how radical. Even the racing 1098 engines found the stock HS4s to be too much carb.

 

[Baz]

Twin HS4s on a street 1275 will be too much carb,

I agree, it was an idle passing thought because I knew those were OK.
I transplanted the (dirty, but now sparkling clean) floatbowls from the HS4s because they have a good needle & seat and no adjustment required. Bolted them to the HS2s and got her purring like a kitten, 12 flats, no problem, all good with the 1275. Only problem is those earlier float bowls don't have a fuel overflow, so I'll have to keep my eye on the lid gaskets.
When I get the bits from Joe, I'll just put them in the B.
If anyone else has these Gross Jets, be prepared for little or no adjustment, because there's no little brass link to bend...If it goes bad, then you get the super enrichment.
$20 new needles & seats /bcforum/images/%%GRAEMLIN_URL%%/driving.gif