The Triumph Dolomite Club - Discussion Forum

The Number One Club for owners of Triumph's range of small saloons from the 1960s and 1970s.
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PostPosted: Fri Oct 20, 2017 9:55 am 
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In the case of Vauxhall, I think they committed the sin of winning an argument: The Lotus head and I think the triple plate clutch and ZF gearbox used on the rally version of the Chevette HS were actually approved for the Magnum homologated before the end of 1975, though the HS was homologated in 1976 (backdated from 1977).

From what I can piece together, what happened was that Vauxhall (DTV) managed to argue with the FIA/CSI that they could use those parts on the HS because, when the FIA removed the 100-off rule, they’d given the following allowance: “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."

That article 260 included the 100-off rule, including a list of “Optional equipment which may be recognized with a minimum production of 100 units per year to equip 100 cars”, and the list included heads with different numbers of cams and valves, gearboxes, overdrives, rear axles, and a shed load more (which is how BL got approval for the 16-valve Group 4 TR7 with the Doly Sprint overdriven gearbox in October 75, without having made any). But that rule did not require that any cars had to be modified to get authorization, just that kits for a “bolt on option”, containing all the parts, had to be freely available for anyone to buy and had to be listed for the car.

However, the extension for their use till the end of 77 doesn't say that the parts and mods should have been authorized and approved for the same car they were being used on, it just says authorized parts, etc., can be used. Now I can't imagine the FIA intended that teams would be able to use parts from other cars because of that allowance, but Vauxhall (DTV) were able to argue successfully that they could.

Assuming it was a mistake by the FIA and DTV used it as a loophole, I have to wonder how the FIA/CSI felt towards them about that. I also wonder how they felt when they discovered in early 78 (ultimately from an article by Graham Robson) that DTV weren’t going to stop using the Lotus head, etc. They sent in the inspectors (Neil Eason-Gibson was one of them), but somehow DTV got the impression from that inspection that they had an extension till May 78, and issued a press release to that effect - though they’d got nothing in writing for it – and sent the car, with the Lotus head, etc., to the 1978 Rally Portugal. The CSI, however, sent a telex to the scrutineers there, ordering them not to allow the car to run unless those mods had been removed.

So Vauxhall had to withdraw from rallying until the differences between the rally and production HS were acceptable to the FIA/CSI. Oddly, it’s said that Blydenstein went on to make the GM 16-valve head better than the Lotus one, at least by the time the 50 (some say 10 percent of the full requirement for a new homologation = 40) HSRs were used to homologate the evolution of the HS into Group 4. And that’s another interesting story.

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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PostPosted: Sun Oct 22, 2017 7:21 pm 
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Creative homologation. The STR91 camshaft was part of a special emission kit. A bigger rad and oilcooler etc. were standard parts for some export countries. When you had on paper a certain number of production cars had those parts fitted it was a standard part so could be used in gp1.

After the rule change in 1976 there were only group 1 cars allowed. Triumph had almost nothing homologated. Ford did. It even didn't homologated the mk2 escort. In 1975 they just homologated a slightly change in bodywork of the escort and could continue.

Jeroen

But I still cant find any reference to where the Gp 2 Doly racers were used, or how the got to modify away from gp 1 for the BTC without listing those changes in the recognition form - however they got approval.

Graham

I used to have a copy of Motor Sport magazine which included an article by one of the journos, about the emerging TR7 Sprint (as an interim before the V8 was launched), which referred to the Group 2 Dolomite Sprint in rallying but no reference to racing. They article was written around a visit to the ST team on the Tour de Corse, they used a retired Gp2 Dolomite Sprint as a chase car for the TR7s.

I also DO still have a copy of the Autocar "Rally Cars Given the Works" book - a compilation of Autocar's "road tests" of rally cars through the 1960s and 70s. It has a test of a "Group 1 1/2" Dolomite and the Group 2 version; according to the article the "Group 1 1/2" car was run on the 1975 Avon Tour of Britain, which allowed that hybrid specification - I think it described the HS8s as part of the hybrid rather than homologated in Gp 1.

If you like I will try scanning in those pages from the book, and can e-mail them or summat? PM me if you'd like me to. I'd simply attach to the thread, but at the max permitted file size they would be illegible.


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PostPosted: Sun Oct 22, 2017 8:06 pm 
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If you like I will try scanning in those pages from the book, and can e-mail them or summat? PM me if you'd like me to. I'd simply attach to the thread, but at the max permitted file size they would be illegible.
PM'ed.

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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PostPosted: Mon Oct 23, 2017 8:55 am 
HS8’s were homologated for use in Group 1 in 1975 so were ok for the tour of Britain.

I cannot see what all the fus is about, 48 Dcoe’s were and still are homologated. I think you are mixing up your groups. Rallying with HS Chevettes, Lotus Sunbeams, RS 1800’s was all done under the ‘Group 4 ‘ banner which had very different criteria to Group 1. It was more akin to group 2.


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PostPosted: Mon Oct 23, 2017 10:18 am 
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If you like I will try scanning in those pages from the book, and can e-mail them or summat? PM me if you'd like me to. I'd simply attach to the thread, but at the max permitted file size they would be illegible.
PM'ed.

Graham
Graham, and anyone else interested :-)

somewhat surprisingly the scans seem to be legible still, after reduction to the file size permitted to post on the forum - attached for your amusement/delectation/delight.


Attachments:
dolomite4small.jpg
dolomite4small.jpg [ 373.13 KiB | Viewed 902 times ]
dolomite3small.jpg
dolomite3small.jpg [ 403.08 KiB | Viewed 902 times ]
dolomite2small.jpg
dolomite2small.jpg [ 414.53 KiB | Viewed 902 times ]
dolomite1-small.jpg
dolomite1-small.jpg [ 340.51 KiB | Viewed 902 times ]
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PostPosted: Mon Oct 23, 2017 10:24 am 
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I think it described the HS8s as part of the hybrid rather than homologated in Gp 1.
Re-reading the article, it's clear my memory was at fault - the HS8s WERE homologated in Group 1. In my defence, m'lud, I hadn't actually read the article for a long time :-) and I DID say "I think" - which is clearly where I went wrong, as thinking is obviously not my strongest suit.


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PostPosted: Sat Oct 28, 2017 2:56 pm 
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I think you are mixing up your groups. Rallying with HS Chevettes, Lotus Sunbeams, RS 1800’s was all done under the ‘Group 4 ‘ banner which had very different criteria to Group 1. It was more akin to group 2.
Yes, they are much the same except for the numbers of cars needed for initial homologation, 1000 for gp2 and 500 (400 from 1976) for gp 4. So Gp4 stuff is relevant, as the original Q was about Group 2.

But I come back to how did the HS8s and Webbers get approved for Group 1. I know that evolutions, like alternative heads, were approved for Gp 4 cars on 40 or 50 cars in about 1977 to 82, and Graham Robson wrote that such evolutions neeed 10 percent of the original production requirement in 76-7 (40 after 1976), when discussing why Lancia went back to the 12-valve engine for 1978.

So were there 500 Dolomite Sprints with HS8s or Webber 48s ever, or could that have been 50 as well?

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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