H6 or HS6 SU Carbs

[Rodbr]

Hints and suggestions requested.

Suggested benefits for benifits of either H6 or HS6 over use of 1 1/2" and combined with extractor tubular manifold.

 

Suggested price for a pair off ebay

 

Turners have quoted £245 for a pair of rebuilt HS6 but obviously the more correct H6 are more expensive.

 

Suggestions and comments greatfully recieved.

[67_gt6]

Hi, if you went with HS6 I think you would want to use a long inlet manifold ie TR4 / 4A

 

Andy

[Ian Vincent]

I will be fitting HS6 carbs on my TR3a but that is because I will be using a TR4a inlet manifold which is a much better design than the log type TR3 manifold. The shorter HS6 carbs are needed to compensate for the length of the TR4a siamesed manifold. I understand that the alternative is a dent in the inner wing.

 

Rgds Ian

[rogeraero]

Hi Rodbr,

For your info I advertised a pair of HS6 carbs here a few weeks ago, no-one was interested so I sold them on Ebay...I got £185 if that helps .

Regards

Roger

[Andrew Smith]

Rodbr

 

Here's the set-up on TuRK; HS6s fitted to a TR4A inlet manifold - hope this helps:

 

 

Cheers

Andrew

[vivdownunder]

Hi Rodbr,

 

1.5" SU's suggests a TR2 with a low port head, and if so, then your best option is to get a high port TR4A head (with the smaller higher velocity ports).

 

Or at a pinch, any other high port TR3-4 head will do.

 

Then you can use the curved branch TR4A manifold, HS6 carbs and tapered aircleaners exactly as per Andrew's car.

 

For extractors, try and get Triumphtune if still available, or something from Neil Revington. Local exhaust shop fabrications can be expensive failures.

 

The larger HS6 carby upgrade increases TR2 fuel consumption by about 4-6mpg.

 

That's about the right price in today's money to rebuild a pair of HS6's.

 

With ebay, price really depends on condition, and who wants the item at the time.

 

Regards,

 

Viv.

[Alec Pringle]

Hi Rod,

 

I can't see the potential benefit of fitting the larger SUs to a low port head, especially on a very early TR2 engine. Reasonable enough to an intermediate Le Mans type head to be sure, and the more so with any subsequent high port head. Performance gain on the low port head is likely to be minimal, whereas the increase in fuel consumption is likely to be wholly disproportionate.

 

The loss of originality is another matter worthy of consideration.

 

If I wanted a quick lump in such an early car then I'd simply build another engine - utilising a later block and head, retaining the original engine unmodified for the benefit of a future owner.

 

Just my thoughts, perhaps a little idealistic ?

 

Cheers,

 

Alec

[Rodbr]

Hi Guys,

All information received and digested. I agree about originality. Until I see what is actually inside my engine ie. valves, bore size etc etc. it is difficult to assess what.if any benefits can be gained until the engine is stripped.

 

Incidently the price from Turners was outright for a pair of refurbed HS6's which I think was very resonable.

 

I was on the track of another "play" engine but think it has fallen through.

[BlueTR3A-5EKT]

Hints and suggestions requested.

Suggested benefits for benifits of either H6 or HS6 over use of 1 1/2" and combined with extractor tubular manifold.

 

Suggested price for a pair off ebay

 

Turners have quoted £245 for a pair of rebuilt HS6 but obviously the more correct H6 are more expensive.

 

Suggestions and comments greatfully recieved.

 

 

In honesty why bother messing with the carbs? Get them rebuilt. Get some different, more efficient air cleaners (K&N?) Mod the head and replace the exhaust manifold if you must. Have you improved the brakes? My TR2 brakes were frightening at 70 plus mph - bit like pulling on a pair of jeans with the bottoms sewn up. Alfin drums helped. (Pete Buckles 49/6 1/2d each I think) - but TR 5 discs from a car I broke solved it.

 

My current TR3A has HS6 carbs on a TR4A inlet manifold with upward offset K&N air cleaners all mated to a TR4A head. Fitted also is an Ivor Davis stainless steel 4 into 1 exhaust manifold (sold in Germany by Bastuck I think) Extra space is provided on the RH side of the engine bay by .... a Hi Torque starter and Kubota/Denso alternator.

 

1. The inlet manifold will not be a happy fit with your low port head - but can be persuaded with a lot of hacking. - Solution - Change the head to high port. (You can fit TR2 inlet and H4 carbs to a High Port though with out much of a fiddle)

2. The float chamber of the rear HS6 carb will foul your heater connection/bulkhead water tube (if fitted) Solution - Move the heater connection to the LH side using a TR4-6 double connector.

3. The choke cable will not be quite long enough. Solution - Make one that is.

4. The throttle linkage will need a lot of thinking about. Solution - Get all the links and mounting plates from a TR4A - (I went to cable.)

 

Notes

5. The economy will fly out the window; the car will not go much better except perhaps at top end revs if you move away from the orig H4 carb and low port set up.

6. The Ivor Davis exhaust manifold fits a treat and does not foul anything. Mine was made to fit a High Port Head - Ask if they do a Low Port version.

7. The Kubota/Denso alternator is a mod I should have done years ago . Needs the pulley modifying on the lathe if you stay with wide belt as I did. Mounting pedestal also needs a bit of lathe work to get it the right length and drilled through 10mm. Wiring simple but needs to be done if you buy a three wire type alternator.

 

Hope this helps

 

Peter W