HTP for 1965 TVR Grantura MK111 1800S

[Jeremy Hall]

In reply to the Seven question, the requirement of International Motor sport has always been that any car complies with a given set of formulaic requirements and latterly Appendix K requires that applicant vehicles complied in period with those requirements.So, in essence, an Appendix K car today should be as it was then.
The Appendix of the International Sporting code which deals with contemporary cars is Appendix J today and in the 1950's was Appendix C.
Appendix C/J has always required that any vehicle must have at least one door.
The Seven has none -so it has never complied, never did an international so is not eligible for Appendix K or an HTP

[LYNX]

Thanks Jeremy. Can anybody give information as to where to look to find out where cars are accepted for events - or is a question of trolling through every series regs? Again PM if not considered on theme. Cheers.

[terence]

Originally Posted by Jeremy Hall

In reply to the Seven question, the requirement of International Motor sport has always been that any car complies with a given set of formulaic requirements and latterly Appendix K requires that applicant vehicles complied in period with those requirements.So, in essence, an Appendix K car today should be as it was then.
The Appendix of the International Sporting code which deals with contemporary cars is Appendix J today and in the 1950's was Appendix C.
Appendix C/J has always required that any vehicle must have at least one door.
The Seven has none -so it has never complied, never did an international so is not eligible for Appendix K or an HTP

Thank god for that,theres enough out there to bugger up the grids already!

[simon drabble]

sorry to restart an old thread but what is the difference between an 1800s and a Mk111? They are both pre 66 HTP papered but presumably the 1800s is better - why?

[Thurner_fan]

From mid-1962 until December 1965 TVR produced the following distinct models:

(i) TVR Grantura MkIII [round tail]
(ii) TVR Grantura MkIII 1800 [round tail, profiled rear number plate]
(iii) TVR Grantura 1800S [Kamm tail but otherwise the same as (ii)]

Only (i) and (ii) were homologated,with FIA papers numbers 68 (dated 10/8/62) and 160 (dated 12/4/64) respectively.

The number 68 papers for the original MkIII specify a 1622cc engine whilst the later papers show the 1798cc 'B' engine that became the standard factory fitted engine from August 1963. It is believed that some pre-August '63 MkIII cars were fitted with the larger engine, but only as a customer requested option.

Almost without exception, the racers out there today build their cars to the spec contained in homolgation papers number 160 i.e. they are racing a TVR Grantura MkIII 1800. In addition to the larger engine this later set of Grantura papers allows them to fit a limited slip differential and 6 inch rims.

The car in (iii) above was never separately homologated but was essentially the same as the car in (ii) except it had the cut-off tail that had been introduced by TVR for use on the later Griffiths. The FIA have chosen to allow cars with this bodyshape to be papered and run as MkIII 1800 cars. This treatment seems slightly at odds with the approach taken with Griffiths, but there you go.

By the way, it should be noted that when Martin Lilley took TVR over in winter 1965 he used up the remaining parts store for the 1800S to continue building a few examples of the same car into early 1966, but he altered the name of the car slightly to 'TVR Grantura MkIII 1800S' and changed the chassis numbering system. This may be the source of some of the confusion.

Note : The later TVR MkIV 1800S was homologated in 1967 and is a different car as it has a longer wheelbase (90"), wider track and the engine moved slightly forward so as to allow the fitment of an MGB heater box.

So, to answer the question, for racing purposes there is quite a big difference between and 1800S and a simple MkIII. However, there is no difference apart from the shape of the tail between an 1800S and a MkIII 1800.

The problem is, most people don't know there is a distinction between and, indeed, two different sets of homologation papers covering the MkIII and the MkIII 1800.

Whilst running the risk of boring the pants off many readers I hope this clarifies things a little.

TF

[simon drabble]

that is very kind - thanks. I am going to PM you

[John Turner]

Superb post TF; very interesting and great clarification.

[simon drabble]

it is John - I guess the point is this, could the FIA decide to take HTP from manx tailed cars if the same way that they have moved the goalposts on the Griffith?

I presume if the difference is purely cosmetic they are fairly relaxed as it is not enhancing performance - or does it?

[John Turner]

Yes, I think that is probably the salient point, if it is the same car bar the tail; it would be a tad churlish to deny an owner of a later car merely because of that. I doubt the car is quick enough to take advantage of the benefits bestowed upon it by the Kamm tail. The Griff on the other hand is a much more serious piece of kit performance wise, presumably. I know that the addition of the Kamm tail to Aston's much faster Project 212 made it a much more stable racing platform than when driven by Graham Hill at the 62 Le Mans, so we know that it is an effective improvement but only at speeds over, what 140 mph?

[FISCracer]

Originally Posted by simon drabble

it is John - I guess the point is this, could the FIA decide to take HTP from manx tailed cars if the same way that they have moved the goalposts on the Griffith?

I presume if the difference is purely cosmetic they are fairly relaxed as it is not enhancing performance - or does it?

A very clear and accurate summary above, Jim

As an owner of both a MkIII 1800 (an original 1800 engined car) and a MkIII 1800S, the only difference I can see is the kamm tail and this arguably increases drag. I would be very happy if the car made 140mph; it certainly has never been near that although I guess it may be possible on extremely long straights such as the 4.5km at the Nordschleife with a 90mph entry speed and the right gearing. Mine pulled almost exactly the same speed up the Kemmel Straight at the Spa Summer Classic as my MGB does in 6 Hours trim.

If there is ever any issue with the eligibility I would argue that it should be with MKIIIs with chassis 7/xxx which should be running 1622 MGA engines as the factory cars did at Le Mans in period.

[terence]

As the FIA have already granted papers for a 'Cam tailed' car,doubt there is any reason not to allow another.

[simon drabble]

Terry I thought that was the point with the Griffs - the rules changed or have I misunderstood the Griff thread?

[Thurner_fan]

Originally Posted by FISCracer

If there is ever any issue with the eligibility I would argue that it should be with MKIIIs with chassis 7/xxx which should be running 1622 MGA engines as the factory cars did at Le Mans in period.

I think you may have a small typo in there. The 7/z/xxx format (where z=B,C or F designated which engine was fitted) was used for the Mk1, Mk2 and Mk2a models and started at 7/C/101.

When the MkIII model with the brand new all round independent double wishbone chassis design was introduced in April '62 the format changed to 8/xxx with the first car being something like 8/525. These cars were produced from June to October 1962 and then again from late 1962 until August 1963, the interruptions caused by various states of financial distress.

The MkIIIs were fitted with the MGA 1622cc engine as standard although, as noted, by special customer order some may have been fitted with the 1798cc 'B' engine which became the standard factory fit from Sept 1963 onwards. At that point the chassis number format changed to 9/xxx with the first such car being 9/663.

The format changed again when the 'Kamm' or 'Manx' tail was introduced on the 1800S and the designation used was 65/5/1XXX until the end of 1965. When Martin Lilley started making 1800S Granturas again in early 1966 he used a new format of 18/XXX starting with 18/001. The cars were essentially unchanged aside from some cosmetic changes to various bits of trim.

Somewhat confusingly the chassis numbering format didn't change with the introduction in mid-1966 of the MkIV 1800S which had a slightly longer wheelbase and different engine position.

All of this comes from careful reading of the various published marque books by the way.

As far as eligibility goes I think it is really up to event organisers to decide whether they want pre-63 or pre-66 cars and then 'police' things accordingly. Classic Le Mans, for example, don't seem to mind having MkIII 1800 cars running despite the fact that the sole outing for TVR in period was 1962 with a 1622cc MkIII. Conversely, a MkIII 1800 would not be invited to join the Carol Spagg/Ben Cussons pre-63 GT series.

[simon drabble]

so it is possible to have a Mk111 with MGA engine and a later chassis which is not like a shopping trolley to drive (not my description but someone who had one!) and it still be pre 63...

[Thurner_fan]

Originally Posted by simon drabble

so it is possible to have a Mk111 with MGA engine and a later chassis which is not like a shopping trolley to drive (not my description but someone who had one!) and it still be pre 63...

The car would have to run without a limited slip diff, use 4.5" rims and have a slightly narrower track than the post-63 cars but, yes, it should still be an OK drive. The chassis would be the same i.e. a huge improvement over the Mk2/2a arrangement. The engine would have to use the slightly smaller 40 DCOE Webers rather than the 45 DCOEs on the MkIII 1800 but it would be allowed to run the alloy crossflow head, just like the 1962 Le Mans cars.

Attached is a sheet which, amongst other data, has a summary of the key differences between the various Grantura homologations. It came from quite a few years ago as can be seen by the typeface!

[terence]

Originally Posted by simon drabble

Terry I thought that was the point with the Griffs - the rules changed or have I misunderstood the Griff thread?

The 1800S is obviously the B engined car Simon,MGAs were never 1800 nor were Griff's.I have a photograph of the Griff "period" "proof" of a supposed international race that the current crop of Griff's sprang from.Be rude not to share it!

[simon drabble]

fascinating reading - again thanks a lot for the colour

[DaveGT6]

Originally Posted by Thurner_fan

The MkIIIs were fitted with the MGA 1622cc engine as standard although, as noted, by special customer order some may have been fitted with the 1798cc 'B' engine which became the standard factory fit from Sept 1963 onwards. At that point the chassis number format changed to 9/xxx with the first such car being 9/663.

I am the happy owner of the above car which is now periodically appearing on a track near you!

[Peter Mallett]

Originally Posted by DaveGT6

I am the happy owner of the above car which is now periodically appearing on a track near you!

[Heightswitch]

Originally Posted by Thurner_fan

The car would have to run without a limited slip diff, use 4.5" rims and have a slightly narrower track than the post-63 cars but, yes, it should still be an OK drive. The chassis would be the same i.e. a huge improvement over the Mk2/2a arrangement. The engine would have to use the slightly smaller 40 DCOE Webers rather than the 45 DCOEs on the MkIII 1800 but it would be allowed to run the alloy crossflow head, just like the 1962 Le Mans cars.

Attached is a sheet which, amongst other data, has a summary of the key differences between the various Grantura homologations. It came from quite a few years ago as can be seen by the typeface!

Jim.
I note your comments regarding wheelbase? I was only aware of 2 derivatives of the thurner designed chassis, IE that fitted to cars up to and including the Vixen S1 and the later LWB chassis first fitted under the Tuscan V8 which later formed the Vixen S2 chassis with a 4" wheelbase stretch.

When you discuss a slightly longer wheelbase between 1800s and MK3 Grantura models are you referring to a pick up point / castor angle change within the original chassis dimensions? i wasn't aware that the chassis on the early thurner cars had changed apart from the adoption of tubular lower wishbones with the 1800S in place of triumph versions??

N.

[Thurner_fan]

Originally Posted by Heightswitch

Jim.
I note your comments regarding wheelbase? I was only aware of 2 derivatives of the thurner designed chassis, IE that fitted to cars up to and including the Vixen S1 and the later LWB chassis first fitted under the Tuscan V8 which later formed the Vixen S2 chassis with a 4" wheelbase stretch.

When you discuss a slightly longer wheelbase between 1800s and MK3 Grantura models are you referring to a pick up point / castor angle change within the original chassis dimensions? i wasn't aware that the chassis on the early thurner cars had changed apart from the adoption of tubular lower wishbones with the 1800S in place of triumph versions??

N.

To clarify, I didn't mention a wheelbase change and I agree with your first paragraph.

I did refer to a slightly narrower track for the earlier MKIII (1622cc) car and if you look at the data sheet I posted you will see the figures I was talking about. The eighth column shows identical basic dimensions, including wheelbase, but the thirteenth column indicates a slightly different track. I believe this data was culled from the original homologation papers for each model and I came by it many years ago amongst a pile of various TVR stuff.

Finally, my name is not Jim. But let's not get into the whole identity thing, there are other threads for that.

TF

[Heightswitch]

Originally Posted by Thurner_fan

To clarify, I didn't mention a wheelbase change and I agree with your first paragraph.

I did refer to a slightly narrower track for the earlier MKIII (1622cc) car and if you look at the data sheet I posted you will see the figures I was talking about. The eighth column shows identical basic dimensions, including wheelbase, but the thirteenth column indicates a slightly different track. I believe this data was culled from the original homologation papers for each model and I came by it many years ago amongst a pile of various TVR stuff.

Finally, my name is not Jim. But let's not get into the whole identity thing, there are other threads for that.

TF

"Somewhat confusingly the chassis numbering format didn't change with the introduction in mid-1966 of the MkIV 1800S which had a slightly longer wheelbase and different engine position."

The above was in a previous post you posted.....

Thanks for the clarification you had me worried for a minute. Regards track widths, again I think this is purely down to the switch between triumph derived wishbones and later tubular wishbones which was probably more to do with TVR being too tight to buy from Triumph than anything else.

You sure you're not Jim lowry??

[Thurner_fan]

Actually, I now see that you are quite right. That was an error in my earlier post when I referred to the MkIV 1800S. The wheelbase didn't change until later with the S2 Vixen, it was just the engine and gearbox that moved slightly forward. Sorry about that, my knowledge of Granturas starts to fade out once we get past December 1965!

Interesting point you make about the possible reason for the different tracks. Useful info for anyone considering builing a 1622cc Grantura MkIII for pre-63 racing.

TF

[Heightswitch]

Originally Posted by Thurner_fan

Actually, I now see that you are quite right. That was an error in my earlier post when I referred to the MkIV 1800S. The wheelbase didn't change until later with the S2 Vixen, it was just the engine and gearbox that moved slightly forward. Sorry about that, my knowledge of Granturas starts to fade out once we get past December 1965!

Interesting point you make about the possible reason for the different tracks. Useful info for anyone considering builing a 1622cc Grantura MkIII for pre-63 racing.

TF

the longer chassis actually did come in in 1967 / 68 with the TVR tuscan Widebody, possibly the trident before that! The Tuscan pre-dated the S2 vixen by a small margin. I have never seen one but there are rumoured to be 3 possibly 4 cars in this country with an unknown number in the states. The Longer chassis was also Bonded into the bodywork as per all the earlier cars.

The holy grail of TVR and a car I would like to see one day as the genuine forerunner of the M series cars on the last incarnation of the thurner chassis.

N.

[clive Mac]

Hi Thurner_fan

I have one of the only MKV 1800SE 1967 only 4 were made it's in gold. As stated in the Peter Filby book (Against All Odds) in the appendix this model and specification is the only section of the book it is mentioned. If you would like any more information on this car you can email me. clivemccormickgason@hotmail.com