Imp HTP

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doc knutsen
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Imp HTP

Post by doc knutsen » Sat May 22, 2010 8:57 am

As people who frequent this forum may have noticed, my son Matt and I run Imps in Historic racing in the Nordic countries.
The rules are as per FIA Appendix K, we run to period G2, ie 1970-72. So, if you try to build a car close to the 1971 Bevan specs, you would be a shoo-in for an HTP, right?
Not so. Unfortunately.
Turns out there are two major obstacles.
One is to do with engine blocks. It seems that the FIA will not allow the use of the 930 Sunbeam block, despite the difficulties of obtaining the "straight-edge" Imp blocks over here. Three of our pool of 998 race engines are built on 930 blocks, while the fourth is a pukka Hartwell-built engine in the Imp block, built for me originally in 1979, and unused since a 1982 re-build.
Having the three "new" engines re-done to pacify the FIA will be a financial stretch, not only in finding suitable blocks and having them machined for 998 liners, but also to find Imp crankshafts, having them nitrided, fitted with steel flywheels, and balanced. With the 930 crank using five flywheel bolts, neither of these items are interchangeable with those of the Imp.
The other problem concerns the transmission. Now, there is no doubt that in period, alle the cars ran 4-sp Knight dog boxes.
However, the FIA has decreed that removing synchro rings was not App K legal back then, so, incredibly, Knight dog boxes are not legal in 2010, in Historic racing cars that purport to reproduce the 1970-72 era.
The Chrysler c/r synchro boxes had ratios for cars running 12" wheels in rallies, but when using rear tyres like those run by Bevan in 1971 the gearing is all wrong. It appears that there is a company in Finland that does any Imp ratios you want, for a synchro box, which is what you need to placate Mr FIA. But I am looking at about four grand to have a new c/r synchro box built up...and I have got three racing Imps...
I have one original synchro box which works pretty well, but my other car, which is the re-shelled 1970 Ivor Goodwin car, came with the gearbox that was fitted to the car in 1971, a Knight four-speed dog box and for the sake of originality on a car with a continous racing history, I am most reluctant to fork out for a "new" and different gearbox.
So, do any of the British Impsters have an HTP? And if so, to whats pecs are the cars with reagrd to engine blocks and transmissions?
Any comment would be much appreciated.
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big J
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Re: Imp HTP

Post by big J » Sat May 22, 2010 10:32 am

Hiya Doc,hope you are well.
It's a minefield all right,I'm afraid I would be unable to help,but I've taken the liberty of asking on a forum which seems to have a lot of guys who race in the FIA series,maybe they would be able to help.

Click here-
http://www.ten-tenths.com/forum/showthr ... ost2695882

All the best with it.
Regards
John.
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SimonBenoy
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Re: Imp HTP

Post by SimonBenoy » Sun May 23, 2010 11:41 am

Hi Doc

Most of the historic racing in the UK is to pre-66 and it would not be a lot of fun to try to run an Imp to the homologation for this period. There are 3-4 Imps which race in the Masters series which is nominally appendix K but with some dispensation to run some improvements.

There are also around 12 Imps racing with the HSCC in a series organised by the HRSR. This allows app K classes but also has a set of HRSR classes where there is more freedom in the rules - we can run 4 or 5 speed SC gearboxes, lsd, brakes are free, we are allowed electronic ign, fibreglass doors, bonnet and boot, plastic side and rear windows and our weight limit is lower at 680 kg WITH driver. An FIA Imp would be 700kg+ without driver.

So we have little experience of the period you are interested in. What is for certain, in period people did a lot more than was ever homologated but I thought that if there was firm evidence of a period mod, the FIA might consider it - but I think that this might only apply if you have the ACTUAL car with documented proof. I was speaking to an e-type owner who has this dispensation for a mod on his car.

Best of luck - Simon
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doc knutsen
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Re: Imp HTP

Post by doc knutsen » Sun May 23, 2010 5:41 pm

SimonBenoy wrote:Hi Doc

Most of the historic racing in the UK is to pre-66 and it would not be a lot of fun to try to run an Imp to the homologation for this period. There are 3-4 Imps which race in the Masters series which is nominally appendix K but with some dispensation to run some improvements.

There are also around 12 Imps racing with the HSCC in a series organised by the HRSR. This allows app K classes but also has a set of HRSR classes where there is more freedom in the rules - we can run 4 or 5 speed SC gearboxes, lsd, brakes are free, we are allowed electronic ign, fibreglass doors, bonnet and boot, plastic side and rear windows and our weight limit is lower at 680 kg WITH driver. An FIA Imp would be 700kg+ without driver.

So we have little experience of the period you are interested in. What is for certain, in period people did a lot more than was ever homologated but I thought that if there was firm evidence of a period mod, the FIA might consider it - but I think that this might only apply if you have the ACTUAL car with documented proof. I was speaking to an e-type owner who has this dispensation for a mod on his car.

Best of luck - Simon
Thanks, Simon and John.
I realise that the pre-66 rules as run in the UK are pretty liberal, but the Nordic Historic series are run to FIA Period F, G or H...period. And for some unfathomable reason, it is said that as long as you can provide documentation that a certain item was used in period, that is fine... except, it does not apply to gearboxes. My Hartwell lookalike Imp, though re-shelled, has a continous racing history from when it was run in the RAC British Touring Car Championship in 1970-73, and in the Swedish national championship in 1975-76, and all the major mechanical components are the original ones. Yet to-day it cannot be run in what is supposed to be an Historic series for 1970-72 cars. I am facing the prospect of having to build an entirely new gearbox for it, from parts that were most certainly not available in the Seventies, ie JK equivalent ratios but with synchromesh. This ruins the originality of the car, besides being an expensive exercise in futility.
Very strange.
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big J
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Re: Imp HTP

Post by big J » Sun May 23, 2010 11:32 pm

Jeez,Doc.That's a bit harsh.
Could you not just lie about it? :lol: :wink:

I might have a block you can have it if it'll help you out.
I'll have a root about tomorrow and see if it's still there.

John
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big J
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Re: Imp HTP

Post by big J » Mon May 24, 2010 5:14 pm

Doc,I found this,which is the technical regs for app K.You probably know them well,but I thought I'd link to it.
http://www.fia.com/resources/documents/ ... 2006_a.pdf

I dont know if the Imp was homologated for circuit racing in period?

If it was,then surely the gearbox was too?

If not,then the article says non-homologated cars can use the period-correct gearbox,which would be the JK one?

John

edit to say-I found the homologated cars list.The ones for the Sunbeam Imp and Hillman Imp mostly seem to be missing.
In that case,surely the point could be made that the JK boxes were used in FIA sanctioned events,as documented in several sources,and it's up to the scrutineer to prove it wasn't?
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knutspeed
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Re: Imp HTP

Post by knutspeed » Tue May 25, 2010 7:46 am

Just to mention how deep this goes; apparently the boxes used by Lotus Cortinas in pre-65 used illegal ratios back then...ie not homologated, or an error on the current homologation document. So another company is making "correct" ratios for App K, which cost the hens teeth. This is rather recent, a few years back, so just think about all the Cortinas needing new ratios. From one provider. Smells kinda like the 5-year rule for seatbelts & seats...
Matthew Birger Patrick (Knutsen)
Sarpsborg, Norway
FIA App K Historic Racing Imp - Bevan Tribute - www.shag.no
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big J
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Re: Imp HTP

Post by big J » Wed May 26, 2010 9:37 am

For those interested,the App J regs for group2 as applied for Docs car are as follows-

) Transmission-gearbox. Mountings are free. The number of speeds of the
gearbox cannot be modified. The ratios are free. The location and type of the
gear lever are free.
Freedom for the scale of ratios implies the faculty of changing the primary and
secondary shafts, as well as the gear and fhe bearings.
m) Transmission-differential. Mountings are free. The differential ratios
are free. A limited-slip differential, but not with a constant and complete locking
effect, may be fitted provided it can be located in the casing without entailing a
modification beyond that allowed under paragraph a)
The transmission shaft between the gearbox and the differential is free.

It specifically says the gears can be changed,so hopefully the FIA will see sense.
The guys on the 10/tenths forum came up trumps,a big thanks to everyone who helped.
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rje
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Re: Imp HTP

Post by rje » Wed May 26, 2010 12:57 pm

John
I don't know how helpful this will be but in a Motor Racing article (Sept '66) it says that Frazer cars used straightcut 3rd & 4th gears (in a syncro box) their Club cars and in 4th Jan 68 Autocar article it states that the Frazer Gp 5 car ran a 5 speed Jack Knight.
Rgds
John
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ImpManiac
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Re: Imp HTP

Post by ImpManiac » Wed May 26, 2010 3:39 pm

^^ Sounds like documented evidence to me. :wink:

Paul 8)
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big J
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Re: Imp HTP

Post by big J » Wed May 26, 2010 5:51 pm

rje wrote:John
I don't know how helpful this will be but in a Motor Racing article (Sept '66) it says that Frazer cars used straightcut 3rd & 4th gears (in a syncro box) their Club cars and in 4th Jan 68 Autocar article it states that the Frazer Gp 5 car ran a 5 speed Jack Knight.
Rgds
John

Thanks John,hope you're well.
The problems seem to stem from the fact that many RAC MSA events were not run to FIA rules,but rather to local interpretations.
The key seems to be the homologation papers,which unfortunatly seem to be missing from the FIA's documents.
The excerpt I quoted above is taken from the FIA's own specifications and hopefully therefore will be enough for Doc to be able to use his existing,authentic period equipment.

I find it astonishing the amout of contradictory and just plain strange regulations there are in "historic" racing.
The craziest must be the fact that authentic,period cars are illegal! Nuts!
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Re: Imp HTP

Post by knutspeed » Mon Aug 02, 2010 11:40 am

An update; we have now managed to get a HTP for our Bevan replica! :D

I haven't got the actual document yet, but it's been given a go by the Gents in Paris. So if anyone else are planning to build a Mk3 GP2 FIA legal car, both Doc and I will be available for questions. I'm even going to scan and upload the HTP when I get it....
Matthew Birger Patrick (Knutsen)
Sarpsborg, Norway
FIA App K Historic Racing Imp - Bevan Tribute - www.shag.no
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big J
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Re: Imp HTP

Post by big J » Mon Aug 02, 2010 11:58 am

Jeez,they made you work for it!
A casual observer would conclude they didnt want Imps out on the track :roll: :lol:
Nice one.
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