SU H6 Conversion

[jake_a]

Just bagged myself a pair of HS6 carbs off a Dolly Sprint on impuluse from ebay. They were a good price so I thought, why not?!

 

I'm on 175s at present so my questions are as follows:

 

1) Will Sprint ones need new needles, etc, for use on the 6?

2) Can I use a 2500 saloon manifold to fit the carbs on my December 1971 CC car, and does anyone have one?!

3) Cheapest way of getting the relevant linkages

4) General power increase to be gained by simply swapping from Strombergs to SUs.

 

Ta!

 

Jake

Edited November 23, 2010 by jake_a

[trelfin4]

We are undertaking a similiar conversion this being PI to Hs6 su carbs .WE have collected su and manifold from triumph 2500s and its mechanical fuel pump still working on linkages as carbs came without them We have a few possibilities will keep you posted.

[jake_a]

We are undertaking a similiar conversion this being PI to Hs6 su carbs .WE have collected su and manifold from triumph 2500s and its mechanical fuel pump still working on linkages as carbs came without them We have a few possibilities will keep you posted.

 

 

Cheers!

[Lee Sellars]

Hello Telfin4

We are undertaking a similiar conversion this being PI to Hs6 su carbs

Keep PI

 

NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

 

Lee

Edited November 23, 2010 by Lee Sellars

[Ragtag]

4) General power increase to be gained by simply swapping from Strombergs to SUs.

 

 

 

I expect I'll be shot down in flames but I wouldn't have thought there is any power gain simply from exchanging SU's for Strombies. SU's are much more tuneable, however, so you would have more potential to gain power in the future.

[Alec Pringle]

Hi Jake,

 

1) Probably. If I recall correctly, there were at least 5 different SU models and 4 different needle specs utilised through Sprint production, without taking into account Special Tuning products . . . . If you're lucky your carbs will still have the identification tag - AUD545/661/663/680 or FZX1257, or maybe AN Other. Burlen Services website should tell you much of what you need to know, but it can be laborious.

 

2) Depends on the head, Chris Witor probably knows more than most suppliers about saloon engine parts and applicability to TRs.

 

3) Some of the Stromberg linkage is likely to be useable, and again refer to Chris Witor.

 

4)None - urban myth ! Simply changing from Strombergs to SUs won't in itself increase power.

 

The Stromberg 175CD is a good and underrated fitment, and for a standard engine I'd rather have one than an SU.

Depends which spec Stromberg you have - probably 3385, if it hasn't been changed to an earlier 3292/3365, or the later 3508/3613/3771. The last two are the most strangulated, Federal emission stuff galore.

SUs are ultimately more tuneable if that's the way you wish to go, but there's an argument for using one of the more 'modern' SU specs if you want to minimise emissions, FZX3045 or somesuch I think.

 

Cheers,

 

Alec

[jerrytr5]

Re no 2)I may be entirely wrong as it's a long time since I had a saloon, but isn't the saloon engine canted over slightly which means that you can't use the inlet manifold as it will be angled upwards on the TR application and you won't be able to close the bonnet - or am I thinking of an entirely different engine?

Jerry

[Bald Rick]

Hi Jake

 

From memory, BAE needles are a good start. You can select a range of richer or weaker needles here: http://www.mintylamb.co.uk/?page=auto.htm

Needles can be purchased from Burlen.

 

Early USA CC cars had different spacing (narrow port) on the inlet ports and although later saloon manifolds will bolt on the inlet ports do not line up. So if you fit a saloon type manifold (or a later USA or a UK manifold) you will likely reduce performance rather than enhance it. These early "narrow port" heads are numbered 516323.

 

Provided you have all the linkage from the SU's it should be possible to adapt the linkage to fit without any extra bits.

 

You are unlikely to gain any power advantage simply from swapping from Strombergs to SU's. Provided te Strombergs are in good condition.I tried it and swapped back to Strombergs.

 

 

Jerry,

 

I think that's the GT6 with bonnet problem.

 

Regards

 

Tony

[johnny250]

Hi Jake,

 

as Tony says, you will need to find a later UK head from a TR5/6 to get the best from the conversion. I'm fairly sure that my manifold came from a saloon and the HS6/wider port spacing head combination works really well. Change the camshaft too and it really starts to fly

 

john

 

PS I had BDM needles for most of the time, fine for standard but slightly weak for my set-up now on BAE which seem just about right.

Edited November 24, 2010 by johnny250

[TONYL]

Hi Jake,

 

as Tony says, you will need to find a later UK head from a TR5/6 to get the best from the conversion. I'm fairly sure that my manifold came from a saloon and the HS6/wider port spacing head combination works really well. Change the camshaft too and it really starts to fly

 

john

 

PS I had BDM needles for most of the time, fine for standard but slightly weak for my set-up now on BAE which seem just about right.

 

Hi John,

Do you have a PI camshaft?

Also does your engine breather go to a catch tank-looks like the breathers on the carbs are blocked off?

And the brake servo take off on the manifold looks a bit special!any details

And the air box-is this a one off?

Sorry for all the questions but doing a similar conversion at moment so any advice greatfully accepted!

Tony

[johnny250]

Hi John,

Do you have a PI camshaft?

Also does your engine breather go to a catch tank-looks like the breathers on the carbs are blocked off?

And the brake servo take off on the manifold looks a bit special!any details

And the air box-is this a one off?

Sorry for all the questions but doing a similar conversion at moment so any advice greatfully accepted!

Tony

 

 

Hi Tony,

 

it's a 'fast road' cam from TR Shop (I think) about 12 years ago.... yes the engine has breathers from rocker box and crankcase to a catch tank.....brake servo take off not special, just using a hose adaptor from original Stromberg manifold with a turned alloy spacer.... Air box is my latest creation with a K&N Apollo filter on the inlet hose and Piper trumpets on the carbs

 

john

[TONYL]

Hi Tony,

 

it's a 'fast road' cam from TR Shop (I think) about 12 years ago.... yes the engine has breathers from rocker box and crankcase to a catch tank.....brake servo take off not special, just using a hose adaptor from original Stromberg manifold with a turned alloy spacer.... Air box is my latest creation with a K&N Apollo filter on the inlet hose and Piper trumpets on the carbs

 

john

 

Thanks John

Looks a great set up

Tony

[rpurchon]

Just bagged myself a pair of HS6 carbs off a Dolly Sprint on impuluse from ebay. They were a good price so I thought, why not?!

 

I'm on 175s at present so my questions are as follows:

 

1) Will Sprint ones need new needles, etc, for use on the 6?

2) Can I use a 2500 saloon manifold to fit the carbs on my December 1971 CC car, and does anyone have one?!

3) Cheapest way of getting the relevant linkages

4) General power increase to be gained by simply swapping from Strombergs to SUs.

 

Ta!

 

Jake

 

here a my set up. saloon manifold home made airbox.bae needles yellow springs .

re correct head.if you have the square manifold. probably early head.unless some ones been in there and changed it .

however the later swept one will probably work just as good if not better than the square one.

even with the mis match of the ports.[the ports wont match up by a 1/5 moon shaped segement on one side]

or simly gring your head to match the inlet.very little difference.if you like the sus look out for a later head.

linkage from the zeniths.

richard

Edited November 24, 2010 by rpurchon

[rpurchon]

Just bagged myself a pair of HS6 carbs off a Dolly Sprint on impuluse from ebay. They were a good price so I thought, why not?!

 

I'm on 175s at present so my questions are as follows:

 

1) Will Sprint ones need new needles, etc, for use on the 6?

2) Can I use a 2500 saloon manifold to fit the carbs on my December 1971 CC car, and does anyone have one?!

3) Cheapest way of getting the relevant linkages

4) General power increase to be gained by simply swapping from Strombergs to SUs.

 

Ta!

 

Jake

 

heres my set up. saloon manifold home made airbox.bae needles yellow springs .

re correct head.if you have the square manifold. probably early head.unless some ones been in there and changed it .

however the later swept one will probably work just as good if not better than the square one.

even with the mis match of the ports.[the ports wont match up by a 1/5 moon shaped segement on one side]

or simly grind your head to match the inlet.very little difference.if you like the sus look out for a later head.

zenith linkage

richard

Edited November 24, 2010 by rpurchon