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 Post subject: HS-8 Carbs
PostPosted: Fri Jan 01, 2021 9:04 pm 
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Location: Nanaimo Vancouver Island BC Canada
I have a set of HS-8 carbs from a Jaguar XJ6 that I have converted to
manual choke. Is there any advantage to running them on a Sprint engine
with a Newman road cam, electronic ignition, standard head, and exhaust
manifold. The exhaust is a Sport type and the head is currently being
freshened with new guides, seals and a surface.
Doug

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 Post subject: Re: HS-8 Carbs
PostPosted: Sat Jan 02, 2021 10:54 am 
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The SU HS8s were fitted to the so called Group one and a half competition cars, but I don't know what cam that was with as the info is a bit confused. So, it's been done a few times. There was a bit of a discussion on this back in 2013 here at https://forum.triumphdolomite.co.uk/vie ... hp?t=26252. There'll be others, elsewhere.

As to the competition use of HS8s, that was, as I understand it, like this:
In 1974 the British Saloon Car Championship series changed to FIA Group-1, "Series Production Touring Cars" needing 5000 built in 12 months to homologate - FIA form of recognition #5542. The Group-1 competition cars would have been as production standard, except for safety equipment, and fitted with HS6s and a standard cam and blueprinted to within the tolerance limits. This is as covered by the FIA's Appendix J of the time. However, at some point after 1974, and by some means, the BSCC authorities relaxed the rules beyond Group-1's requirement that to make modifications affecting the performance of a car, you had to build another 5000 in 12 months with that option fitted. This relaxation then allowed the change to HS8s. That was, as far as I can discover, without any production or selling of cars with HS8s fitted - though I believe there was a kit from special tuning. That freedom to change carbs was a thing in FIA Group-2; hence, them being called Group one and a half cars. Group-2 cars were also allowed to change brakes, more or less as they liked including fitting disks on the back. But I can't find even suggestions this was done to the Group 1 1/2 Dolomites. There are suggestions they did use a different cam, as would also have been allowed in Group-2, but I haven't found any real details on that - how that happened is supposed to be different from how they were allowed to use HS8s, and it's at least implied here and there that it was bending the rules a bit. But I wonder if it's the same relaxation of the rules for Group-1 and the suggestion of rule bending is an embellishment on a gap in information.

Graham

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The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Tue Jan 05, 2021 9:22 am 
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These carbs were homolgated as std. equipment for some export countries. I believe the gp1 weber set was called an emission kit std. for some export countries. Not bending the rules and not gp 1,5. All legal gp1.

I would not change the std. cam and only fit the hs8 carbs.

Jeroen

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 Post subject: Re: HS-8 Carbs
PostPosted: Tue Jan 05, 2021 10:25 am 
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Hi Jeroen, why would you not uprate the cam? Surely with the extra mixture being passed through the larger carbs it would make sense to do so?

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 Post subject: Re: HS-8 Carbs
PostPosted: Tue Jan 05, 2021 1:57 pm 
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Quote:
Not bending the rules and not gp 1,5. All legal gp1.


Jeroen
In which case, you'll be able to identify at least some of the 5000 cars fitted with these carbs, as required by the FIA's Appendix "J" to the International Sporting Code Classification, definition and specifications of cars 1971, Articles 255, 256, & 257.

Specifically :

Art 255 - Definition: touring cars built on large series production terms. These cars shall compete in an event without having undergone any preparation likely to improve their performances or their conditions of use. The only working authorized is normal maintenance or the replacement parts damaged through wear or accident and the modifications and additions explicitly authorized hereafter under article 257. Except for what is explicitly authorized any part damaged through wear or accident may only be replaced by an original part which must be exactly the same as the one for which it is substituted.

Art 256 - Minimum production and number of seats: series-production touring cars shall have been manufactured in a quantity of at least 5,000 identical units and offer at least 4 seats, except if their engine cylinder-capacity is inferior or equal to 700 cc. In which case the manufacturer may deliver them as two-seaters.

Art 257 is a bit too long to copy to here, but it does not include allowing for alternative carburetors or such. As I understand it, the HS8s are special to the BSCC and, perhaps to some other series not explicitly FIA, i.e. Group-1.5, and the Webers are Group-2. They would not need explicit identification in the Form of Recognition (#5542). If there was some use of Webers in Group-1.5 I ain't aware of it. Without the production of 5000 cars fitted with those carbs, neither would be permissible in any context of FIA Group-1.

There is a clause of Appendix J relating to export options; however, that is part of Art. 260 (clause y) relating to Group-2 approval requirements, and has no relevance to Group-1.

As to the Group-2 approval of the Dolomite Sprint, the first I can find record for is from 1-4-1974 (amendment 4/3V) covering some items that needed no production of cars (or kits, like those approved under the 100-off rule), but needed identification for approval (under Art. 260 clause bb). These include brakes and wing extensions, etc.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Tue Jan 05, 2021 2:09 pm 
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The article of appendix J 1971 allowing alternative carbs in Group-2 without identification is Art 260 clause y:

Engine-induction system and elements: the induction system is free. Yet direct injection may only be used on an engine for which the fitting of a direct injection system has been originally provided for in the manufacturing. Ditto for supercharging.
By the term "originally provided for in the manufacturing" is meant: normally
fitted on cars delivered to purchasers, and mentioned on the recognition form or the
manufacturer's catalogue.


Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Tue Jan 05, 2021 2:41 pm 
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Here's a scan from the Doly's Form of Recognition showing the induction stuff for the Group-1 approval, showing the carbs allowed in Gp-1. There are no amendments for Group-1, or any others, showing the HS8s or Webers. In which case, they would only ever have been eligible for FIA Gp-2.

Image

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Thu Jan 07, 2021 10:10 pm 
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I have a full set of original FIA Relief stamped homologation set of documents and Special Tuning data/drawings.

Here is your HS8 gp1 homolgation:


Image

And here the weber gp1 homologation:


Image

After 1976 the gp2 rules altered very much and Triumph had to homologate a lot of parts that were legal under gp2 before 1976 and illegal after 1976. The four link rear suspension for example. Before 1976 pick up points and layout were free and after 1976 a gp2 car had to have the std pick up points for the suspension. The cheapest option was to use only gp1 cars from then and only homologate what was needed to use a gp2 engine in a gp1 car.

Jeroen

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 Post subject: Re: HS-8 Carbs
PostPosted: Thu Jan 07, 2021 10:26 pm 
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Quote:
Hi Jeroen, why would you not uprate the cam? Surely with the extra mixture being passed through the larger carbs it would make sense to do so?
I alway's call an SU a "delay carb". Not like a weber trottle valves open and squirt some fuel in when accelerating.

A blueprinted sprint engine with std cam and HS6 carbs can have around 140hp on the rear wheels. Head and cam and exhaust manifold in std form (blueprinted) are very good. Using an "uprated" cam for a road sprint and using HS8 will gain in top revs but loose a lot at lower and middle making it not so pleasant to drive in daily traffic.

Just putting HS8 on a std sprint without blueprinting will gain not so much overal but will still be driveable in daily traffic. Just putting HS8 carbs and an "uprated cam" in a std non blueprinted engine will make things worse.

Jeroen

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 Post subject: Re: HS-8 Carbs
PostPosted: Fri Jan 08, 2021 5:21 pm 
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Quote:
I have a full set of original FIA Relief stamped homologation set of documents and Special Tuning data/drawings.

After 1976 the gp2 rules altered very much and Triumph had to homologate a lot of parts that were legal under gp2 before 1976 and illegal after 1976. The four link rear suspension for example. Before 1976 pick up points and layout were free and after 1976 a gp2 car had to have the std pick up points for the suspension. The cheapest option was to use only gp1 cars from then and only homologate what was needed to use a gp2 engine in a gp1 car.

Jeroen
Amendments 7 and 17 are not in the official FIA Form of Recognition #5542 stored on the FIA Website, which goes as far as amendment 29 dated 1 Nov 1979. Neither are these amendments listed by FISA (as CSI, who determined what cars met the rules, became in 78) in the valid amendments for the transfer of the car to group A. So I wonder, do you have an earlier paper copy of the FoR? The date of the last amendment on your copy and the presence or lack of the Group-A transfer info might throw some light on it.

So, it's not clear to me what the status of these two amendments may have been or when and how long and under what circumstances they were valid. Also, I've never heard of the leave on intent to manufacture or the reduction on cars needed to re-approve options applying to Group-1. So if those amendments represent above-board approvals by the CSI they should have been fitted to 5000 cars.

I have to admit I don't understand why some amendments have FIA stamps, like 7 and 17, and others have CSI stamps. But I suspect it matters in international competitions, because (as I understand it) the autonomous CSI/FISA wrote the rules (published by FIA) and directed their scrutineering, not the FIA itself. Their role in governing international competitions being why Bernie Ecclestone and Max Mosely took on them, not the FIA, in the FISA-FOCA war of the early 80s.

The Group-2 rule change for 76 isn't very complicated. Basically the the FIA/CSI removed the 100-off rule (clause bb - Optional equipment which may be recognized with a minimum production of 100 units per year to equip 100 cars) from article 260 of Appendix J 1975 when they published appendix J 1976 in Dec 1975 (having warned the changes were coming staring in Dec. 74). You can compare Art 260 1975 with Art. 261 of 1976 (there was a numbering error with two Art. 253s in 1975) where clause cc (- Optional equipment which may be recognised without a minimum production) of 1975 simply moved up to become clause bb of 1976.

The ban was given in Art 261 1975 (for Group-2 cars) as "NB: Mechanical elements recognised in Group 2 before 31.12.75 as well as the authorised modifications according to the prescriptions of Art 260 of former Appendix J can be used until 31.12.77 for rallies. The car will be automatically transferred to Group 4."

It seemed that Vauxhall tried arguing that that this note didn't say they can "only" be used until 31.12.77, when the CSI were threatening to ban the Chevette HS in March 1978 (which they did in April) for continuing to use banned bits. But Dealer Team Vauxhall had got that car approved in 1976 (backdated to 1975) through another loophole in the ban - it missed limiting mod to "... the car for which they were approved..." So they took the Lotus 16-valve head that was approved on the Magnum and used it on the Chevette, without it ever being approved on the Chevette. I suspect that driving the Chevette through that loophole had royally p155 the CSI off. So much so that they weren't having it again in 1978, and they got Cicero in to explain exceptio probat regulam in casibus non exceptis to DTV. It possibly didn't help that the new head of the CSI in 1978 was an ex member of the French SS (who are said not to have been very nice people) - though he only joined as a spy for the resistance, so he said.

It is interesting that it was a general ban on stuff approved under Art. 260, not just the 100-off rule, which rule had caused most complaints to the CSI as being unsporting. That meant that lots of Group-2 options needed to be re-approved, but those that had been approved under clause bb of article 260 also needed some production. This is what happened to the 16-valve head on the TR7, Group-4 mods also being covered by article 260 and a similar ban (that's what got me involved in all this in the first place), but I don't know that there were any 100-off rule mods from production standard on the Doly for 1976, etc. If there were, they would also have needed production to gain re-approval.

That production should have been 1000 cars for Group-2, but then it should have been 400 for Group-4, and the CSI accepted 50 in a number of well documented cases, notably the Chevette HSR, and the aforementioned TR7 16-valve head. There's a couple of less clear cases as well in the Porsche 944 and the re-approval and transfer of the Group-2 RS1800 into the Group-4 Escort RS on a second batch of somewhere between 50 and 58 production (BDG engined) RS1800s built in 1976/7. So, it's possible that any 100-off rule options would've been reapproved on far fewer than 1000 cars, perhaps only 50 - those cars would have to have been "meant for the normal sale" and, in the case of the 50 or 60 TR7 Sprint and the (perhaps only nearly) 400 FHC TR8 specials, those were sold-off not scrapped.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Fri Jan 08, 2021 6:01 pm 
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Some homologation sets online aren't complete because of interest. I think the FIA has put online what was laying around and doesn't bother if it's complete or not. There is a lot homologated for the gp1 engine wise, suspension and brakes from 1977/1978 to have a competative gp1 car. From 1978 on the thicker chromium engineblocks are also homologated in gp1. It say's std engineblock but from different supplier.... Some of the forms have the older type FIA stamp and some the newer and all have a relief RAC stamp.

In the Special Tuning build sheets they also suggest to fit the homologated HS8 or Weber kit building a gp1 car.

Jeroen

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 Post subject: Re: HS-8 Carbs
PostPosted: Fri Jan 08, 2021 6:09 pm 
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Doesn't explain why those are not in the list of amendments transferred to FISA Group-A or the issue over FIA vs CSI stamps. It's not an age thing, FIA gave autonomy to CSI in 1922 or something.
Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Mon Jan 11, 2021 8:33 am 
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Doesn't explain why those are not in the list of amendments transferred to FISA Group-A or the issue over FIA vs CSI stamps. It's not an age thing, FIA gave autonomy to CSI in 1922 or something.
Graham
You are completely right, that doesn't explain.

Jeroen

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 Post subject: Re: HS-8 Carbs
PostPosted: Mon Jan 11, 2021 8:46 am 
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Neither does it explain where are/were the homologating cars fitted with HS8s and Webers. Appendix J is absolutely clear on the need for such cars for modifications that affect performance of Group-1 cars, and the need of the ACN, in our case RAC, and CSI to determine this requirement is met. It may not have needed the full 5000 as is shown by Group-4 homologations on 50 cars not 400. However, Group-1 is supposed to be for full, not limited, production cars.

That there are/were none of these homologation specials, or so few they are invisible, that the approvals are not stamped by CSI, and that they were not valid when the car was transferred to Group A, may suggest these approvals relate the the Group-1.5 for use other than in international competition.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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 Post subject: Re: HS-8 Carbs
PostPosted: Mon Jan 11, 2021 9:43 am 
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All the forms have FIA/CSI stamps and relief pressed in stamps. The cover of the set say's "to be valid each page must have the embossed stamp" and all pages have. The works gp1 rally cars had webers fitted in 1977 as on the homologation form when BL didn't use gp2 cars anymore. In 1975 for the Broadspeed touringcars the HS8 were homolgated for gp1 and were fitted on these cars as proper homologated gp1 parts. The same for the gp1 homologated vented discs.

There are no gp1,5 cars as mentioned before. All these parts were properly homologated by BL on FIA documents. No mistery parts or vage constructions or illegal. Most have, to be seen on pics I have posted before, "standard for some export countries" or "different supplier" mentioned. That would be enough to qualify as a std part so homologated for gp1 as std part i suppose.

I can't help the information available on the net you are still reffering to isn't complete but the homologation set for the sprint is much larger than the few scans to be found online.

Jeroen

Already an answer to your next comment, you are completely right.

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