Opinions wanted on carb options.

[Mychael]

My car (with 1098 engine fitted & extractors) currently has a pair of 1 1/4 'HS' type Su's fitted.

I'm not as familier with these type as I am with the earlier 'H' type. In any case they are in need of overhaul with shaft re-bushing etc.

So I'm wondering whether to stick with these or go for a single 1 1/2 SU (drove a car with one fitted and liked the smoothness and low down torque) or get a Weber.

Mike

 

[JPSmit]

Either way, I vote stick with the SU

 

[Mychael]

How hard is it to obtain the different inlet manifold to run the single 1-1/2 ?
Come to that how easy it to come by a good 1-1/2 carb? I'm a bit out of touch on stuff.

 

[JPSmit]

How hard is it to obtain the different inlet manifold to run the single 1-1/2 ?
Come to that how easy it to come by a good 1-1/2 carb? I'm a bit out of touch on stuff.

This month's Practical Classics asks the same question about 1275s. Apparently the manifolds are available - they were saying 100 pounds on ebay. In truth, by the time you have paid for a manifold and another carb (and likely had that carb rebuilt) and shipping to <span style="text-decoration: line-through">the end of the world</span> Oz, you have spent more than the money to have your carbs (I thinks they are HS2s) rebuilt. I would suggest you get them rebuilt. They are sweet and simple little carbs, they are the carbs the car was designed for and even though I run one HS4 (mine had a Zenith Stromberg) I have to admit that twin carbs ALWAYS look cooler!

 

[Trevor Jessie]

I like JP's logic. Rebuild what you have. Once properly tuned they work great.

 

[Gundy]

I experienced less low end power with a single HIF6 SU
when compared to twin HS2s. This a car with a warmed motor and headers.
Experiences will vary but other than the carb change the
motor setup wasn't touched.
Both were with professional setup carbs.
I do think at the extreme top end the HIF6 had a teeny bit more power.
The twin HS2s are much more throttle responsive
and around town are perfect.
That and they just look right.

Rebuild...you will not regret it.

 

[aeronca65t]

I'm racing on the standard carbs. No probems.

 

[The_architect]

Hi Mychael. Eventually someone will come along here and point out that the HS2s do not have bushings. It is the shaft that wears out. So whatever you've read about having the two carbs reamed out by a machinist with a special reamer does not apply. You just replace the shaft! The other parts--the jets, needle valves, throttle plates, are cheap and there is a ton of info on the web about how to do it. Charlie

 

[jhorton3]

I'm not an expert on SU carbs, and that's probably why I've always had issues with them. I couldn't get my twin carbs to behave on my 1275, so a few years ago I went outside the box and put together a single carb configuration using a Mikuni HSR 42 on a single intake. I also caught a lot of grief for breaking with tradition. I think someone has developed a kit now for A series motors. Mine fires up at the most after two quick starter bursts, and idles evenly. On twisty roads it's fine as well as on the interstate. I'm not racing mine, just an occasional drive for enjoyment.

 

[Mychael]

Thanks for the input guys. I'll take the carbs off over the next week to have a really good go at them myself first on the workbench before I make a final decision.
My engine (1100) is not worked, has extractors and 2 inch pipe and I'll be fitting an electronic ignition but that's about it.

It's got rego now and I want to use the damm thing a bit before pulling it apart again.

Mike

 

[alcatone]

Hi could i have a part number for the K and N filters on Gundys car please Tony

 

[RickB]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Hi could i have a part number for the K and N filters on Gundys car please Tony[/QUOTE]

Hi Tony, welcome to the BCF!

What you need to know is that just getting a pair of those K&N's won't do the whole thing, other parts are needed to mate them to a pair of HS2 carbs.
They are designed to fit over velocity stacks with the right outer diameter and depth.

Hap Waldrop has produced some of them for the HS2.

If you are using and HS4 or HIF4 carb with the 1.5 inch intake then you can use the velocity stack from a stock MGB carb setup, the ones that are inside the stock filter cans and are connected to the fronts of the carbs.
It's best to counter sink the fasteners for this.

I did some searching and found this thread: Click Here

 

[RickB]

Hi could i have a part number for the K and N filters on Gundys car please Tony

Just found it in another thread: K&N filters #RU-4410

https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/367861

 

[Hap Waldrop]

Yep, KN RU-4410, you'll need ther special velocity stacks to go with them, but there are vendors ion the Uk that make them as well, her's some pics of the stacks with the air filter removed.

 

[Hap Waldrop]

another shot of the whole assembly.

 

[alcatone]

Thank you both for your replies,just what i needed thanks Tony