Stromberg / SU adapter

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Sal
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Stromberg / SU adapter

#1 Post by Sal » Fri Nov 19, 2021 5:41 am

Hello there,

Car - MK1 2000

I’m having problems with my Stromberg’s so want to swap them for the SU’s. I have seen an adapter kit where the SU fits onto the Stromberg manifold but can’t find out where to buy them, anyone know?

Cheers
Sal

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Re: Stromberg / SU adapter

#2 Post by Charles H » Fri Nov 19, 2021 9:06 am

Not sure about an adaptor, but IMO the Strombergs are much better built and work very well indeed compared to the similar aged SU.
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Re: Stromberg / SU adapter

#3 Post by Carboy0 » Fri Nov 19, 2021 9:39 am

TR7 inlet manifolds were originally designed for Strombergs but Triumph later fitted SUs by fitting a hard rubber adaptor plate. From memory they are 1.75” diameter, so might not fit a manifold that started with 1.5” SUs.

I have a TR7 manifold in the garage, I’ll measure it and take some pics over the weekend if you want.
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Re: Stromberg / SU adapter

#4 Post by johnnydog » Fri Nov 19, 2021 11:48 am

Charles H wrote:
Fri Nov 19, 2021 9:06 am
Not sure about an adaptor, but IMO the Strombergs are much better built and work very well indeed compared to the similar aged SU.
I am in agreement with Charles on that one - Strombergs are very easy to work on and to set up - the only issue I've ever had with them is the float valve (needle valve) can leak and allow excess fuel into the float chamber which then enters the air filter box or escapes through the brass link tube into the air intake. This issue is usually down to reproduction / new replacement Zenith valves which don't seem to be manufacturered to the same quality as the originals. Replacing them with good used valves has always cured the problem for me.
I personally would try to remedy the issue with the Strombergs, which, even with a complete overhaul, would be easier than faffing about with inlet manifold adapters, which will also reduce the available space between the carburettors themselves and the suspension turret.
Which SU's are you thinking of using? HS4s, in my opinion, aren't a particularly good carburettor compared with the bottom adjustable Strombergs, or HS6's.
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Re: Stromberg / SU adapter

#5 Post by Carboy0 » Fri Nov 19, 2021 9:54 pm

Picture here taken earlier in the year, I’ll measure it up when I have found them in the garage.
76196C7B-049A-47D8-A038-95BD9ECA7E28.jpeg
B5A16DCC-15E9-426B-B32F-5DB6C99C830A.jpeg
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Re: Stromberg / SU adapter

#6 Post by Sal » Sat Nov 20, 2021 7:32 pm

Thanks all as always for your comprehensive responses.

Carboy, thanks for the pics but they won’t fit mine.

Update - I removed the Strombergs for the umpteen time and took the jets out, float bowl off and refitted and I seem to have cured all the leaks. I think that maybe something wasn’t sitting/seating correctly.
The only thing I need to do now is set them up correctly. I have unscrewed the jets at the bottom of the carbs and it now sounds sweet but would probably benefits from someone with an air flow meter thing just to double check every thing is balanced correctly.

I have also rectified the oil filter leak. It was a good garage day today!

Sal

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Re: Stromberg / SU adapter

#7 Post by Sal » Sat Nov 20, 2021 7:37 pm

Meant to also say that the only SU’s I have are HS4’s and I’m having a 2.5 engine built so probably need to look around for a good set of HS6’s

If any one knows of any then please do let me know

Thanks
Sal

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