Pages 72 - 74 in the book 'The Magnificent 7' by Chris Rees has pictures, identifying features and seems to explain the difference very well. 

is it a BDR Yes.

is it an HPC No.

All I wanted to know was if it is a BDR aside from the engine being a BDR. In other words could it be some other model with a BDR engine in it. Answer: No. It is a kit built BDR, based on the same "universal" chassis as the HPC.

I suppose one could claim it is an HPC, but it isn't. The HPC was a marketing tool with a parts upgrade package with a driving course thrown in, which by the way, I have in fact endured in this very car with the very same slightly older John Lyon , but it wasn't driving course funded or package upgraded or built by Caterham in the 1980s so it's NOT an HPC. In fact as far as I can determine, it was bought before the HPC was launched in October 1986. Mine is registered in 1987, I'll have to check the bills for the kit purchase date. And in any case the chassis number isn't an HPC, these models not being available in kit form, to have the HPC chassis number it MUST be factory built, is what "everyone" tells me.

Now then, all the docs given to me at time of purchase now to hand;

There is  1999 (plus year 2000 update) build manual, clearly not much use as a 1986/7 reference.

And a

Caterham Super Seven 1600 1986 

Assembly Guide. And an introduction with history.. "The Lotus Seven was originally launched to the public at the Earls Court Motor Show in 1957 ...."  "it was not until 1968 that the Series 3 Seven was launched ..."  "In May 1973 Graham Nearn's Caterham Cars took over all the remaining Seven parts, jigs, moulds and, most importantly, the manufacturing rights from Lotus. Subsequently about 40 series 4 Caterham Sevens were sold until it was phased out largely due to problems with component suppliers in 1974."

"Initially Caterham Sevens were fitted with Ford Escort axles, but supplies of this axle dried up in 1981 with the introduction of the FWD Mk III Escort. The replacement Morris Marina/Ital axle was fitted to approximately 500 Caterham Seven Series 3's between 1981 and 1986 when it too ceased to be available. Seeing the writing on the wall for small beam axles, Caterham then designed their own De-Dion rear suspension, based on Ford Sierra parts, which was introduced in 1986.

At much the same time, supplies of Ford Escort Sport semi-close ration gearboxes also dried up so the chassis was re-engineered to accept the 5-speed gearbox from the Sierra."

So the changes for 1986 were fundamentally huge. Redesigned back axle and chassis. 

it goes on:

".......the Ford Cosworth BDR with double overhead camshafts and 16 valves became available in 1985 followed by the even faster "HPC" specification in late 1986."

and here we are about kits:

"...latterley Caterham Cars have been unable to keep up with demand for semi-complete component cars and hence are once again supplying cars as full kits for "home assembly" by persons not engaged in the trade...."

I'm going to precis from here.

ORDERING SPECIFICATIONS

CHASSIS

Three chassis cockpits possible, short, long, long+dedion

Dedion not available as short cockpit.

Mine is Long cockpit dedion - as confirmed by the chassis number.

ENGINES

Ford 2265E 1600 cc crossflow

Cosworth BDR 1600

"We strongy recommend the use of the Ford 2265E engine and in particular the later 711M block which is considerably stiffer than earlier units. These engines are used in Formula Ford 1600 racing and are not only cheap and readily obtainable new and second hand, but also very robust and easilt tuneable."

There is reference to the Supersprint 1700cc specification, 136bhp at the flywheel. My car is 169bhp at the wheels (on the dyno).

aha! My car has always had what I now know to be "a special bellhousing adapter provided by Caterham Cars..." this is a 25mm alloy thing that adapts for the long input shaft of the type 9 gearbox Ford part number 1645418 for Sierra XR4i.

I guess it was only in later years that input shafts were cut down or available; these days long input shafts are practically impossible to find. I needed one to convert a cc sixspeed box for the BDR. Thank you to Phil at Road & Race Transmissions for that.

"....the RS2000 provides both the optimum nine inch rear drums and 3.54 final drive ratio." My BDR has both these, on dedion. I am assuming my drums are 9". The diff was LSD 3.54. Currently open diff 4:1 . The original diff is stored.

WHEELS & TYRES

All 13 and 14 inch wheels. My car has 15" wheels. Again currently on 13" but the original 15" Revolutions (same as my RS2000)  are stored.

OPTIONAL EXTRAS - I will add YES when present.

Heater - YES

Cibies - YES

Rear Wing Protectors - Stainless steel - YES - To be rivetted, mine are bolted.

OIL COOLER - YES - I think 

Chassis manufactured after May 1987 locate the oil cooler in front of the radiator. Mine is behind (if fitted - car confusion)

HEADLAMP STONE GUARD - NO

BDR EXHAUST SYSTEM Large bore 4:1 manifold. Don't know need to check old pics. Currently has Powerspeed exhaust.

AIR HORNS - NO

ELECTRONIC IGNITION - YES - They don't name it, but it's Lumenition (described perfectly in the book) and now removed in favour of modern replacement inside the dizzy cap. I still have the old one, in fact two.

 BOOT COVER - YES 

TONNEAU COVER - YES

WIND DEFLECTORS - YES - "Ten times more impact resistant than glass". 

REAR ANTI-ROLL BAR 

My car has a dry sump and the build manual includes the fitting instructions for it, which I find persuasive this was the manual actually used, also all the parts checklists are ticked or bits marked "missing" which sounds like all kit purchase experiences.

Right at the back, last page of what appears to be the Assembly Guide actually used for the build is a

1700 SUPERSPRINT engine Kit £520 plus VAT.

it says "it is recommended that the flywheel is lightened by 6lbs and the engine is balanced". 

No mention anywhere of the engine itself.

The above is consistent with what Geoff said to me when I was buying the car, that the engine came from Cosworth and was modified. It sounded like Cosworth did all that but Guy Munday says Cosworth never built engines, it would have to have been an engine builder somewhere.

So at this point I have a 711M Block, a 1700 Supersprint kit, no engine from Caterham themselves: all of which points to an engine builder somewhere. The 1700 Supersprint kit includes 40 DCOE Webers. Mine has 45 DELLORTOS. 

Also the 1700 kit was said to be good for 135bhp but mine has 169 (at the wheels). Assuming the dyno is/was right in 2004.

updates:

Chassis number is KLD0239R 

Engine is CE9797COS

​I seem to recall looking in to the engne number years ago, the CE may be Cosworth Engineering, suggesting indeed a "direct from Cosworth" heritage.

http://www.race-cars.com/utility/coswrthr.htm

1700cc

​Date of 1st reg 25/9/1987

Can't find an invoice for kit purchase, but assembly manual is 1986 .

BDR 1983 1601cc 120 Bhp. BDA kits for Caterham Super Sevens, also 1.7 litre and 150, 170 Bhp.

http://www.cosworth-technology.co.uk...1_history3.htm
http://www.cosworth-technology.co.uk...1_history4.htm

THE ABOVE DON'T WORK

https://en.wikipedia.org/wiki/Ford_Kent_engine

This series of engines became known as the Kent engine because Alan Worters, the company's Executive Engineer (Power Units), lived across the river from Ford's Dagenham plant in the English county of Kent.[1]

Originally within Ford, it is said that the Kent name was actually born with the A711 and A711M blocks (commonly called the 711M block) with square main bearing caps for the Crossflow series, which represented a vast improvement in the durability of the engines. However, the name caught on to be used outside the company to include pre-711M engines as well.

https://en.wikipedia.org/wiki/Cosworth

http://www.mahle.com/mahle/en/news-and-press/press-releases/mahle-plus-cosworth-technology-equals-mahle-powertrain.jsp

http://forums.autosport.com/topic/47541-cosworth-a-quick-history/

1986 Project BDR:modified BDA for Caterham Cars, sold as conversion kit 

https://en.wikipedia.org/wiki/Cosworth

In 1983, the BD series saw its second road engine incarnation (the first being the original BDA and BDB), the BDR, which was a BDA or BDB sold in kit form for the Caterham Super Seven in 1601 cc (120 bhp) and in 1701 cc (130 bhp) formats.

I have one of the 62 'HPC' S3s (verified by chassis number) and my car left the factory with cycle wings, not sure why it's claimed they didn't.

Derek.

Chassis KLD0xxx I forget the xxx for now, something like 203

from the F A Q

K = Kit built

L = Long cockpit

D = DeDion? (? is per the FAQ)

I know (builder told me) he bought the engine NOT from Caterham, but (he said) from Cosworth because he wanted it modified. 

It has Nickel plated front suspension bits, which I now see (Magnificent 7s p64) was something supplied on the 1982 25 years Celebration edition, only seven being completed finally in 1983 so wondering if these parts were simply off the old stock shelf in 1986, only three years after the Celebration edition was marketed.

In 1986 (the year "my" kit was purchased in CKD form Geoff described how all the bits fitted in the boot of his car saying it was indeed completely knocked down) 

the "1700 BDR-based model from Caterham which was launched at the October 1986 Motorshow"

So there it is. A non HPC 1700 BDR. edit I now see that most BDRs were not HPC, they being only 62 in number.

It goes on to say " An optional package of improvements lifted the standard BDR to the hallowed HPC spec, which was first tried out on John McLean's car in 1986 (chassi number 4589)."

To check list against mine the package list does mine have the bits?

Limited slip diff YES

Rear anti-roll bar I think so can't remember

Individually adjustable seats - One is, one is not ! On this my guess is he left out the adjustment on purpose. I think it is the passenger seat that is adjustable, yes it is. I put things behind it whereas the driver's seat is against the rear bulkhead.

Pages 72 and 63 suggest my BDR chassis would have been the new universal version, which came out in 1986 for five speed box cars; mine has a five speed BGH box, exchanged as I recall in 2003 with BGH for the original five speed box in the car when I bought it. It is conceivable it had a universal chassis and a Ford Escort Sport 4 speed, but I don't think so; otherwise the BGH exchange would not have been a straight "swop" and if it were not the universal chassis, fitting the five speed BGH would have required chassis modifications. This explains why whenever I have looked at an HPC it looks just the same.

I have the original purchase invoices from Caterham; must have another look through those

CC would not classify a car as BDR if they did not supply the engine. 

There was a rumbliing about being able to buy the kit CKD or not, I forget the story.

She has Dellorto 45s - NOT Webers, again a variation appearing in various previous incarnations.

I am confused here because Geoff told me they were 48s and said it took him 15 years to get the jetting right. Then another 15 years for me to notice they are 45s...

Yes I thought that was an odd claim, good to hear I am not alone.

Some interesting BD engine history 

 here https://motor-car.net/cosworth-engines/item/13787-cosworth-bda-engines

" for example, KLDxxxxR,
where K=supplied as a kit; L=long cockpit**; D=de Dion; x=the digits, normally the same on the chassis plate used for the engine No., where chassis and engine were both Caterham-supplied; and R=right hand drive."  from here: https://www.caterhamlotus7.club/comment/2304296#comment-2304296

just in case not in my older above. The builder (Geoff Mansell) said he got the engine direct from Cosworth, but modern folk tell me Cosworth never supplied engines. I very recently saw the engine has very long conrods which means they are "ARP" or one other I forget. This means a new sump pan requires massive modifications to allow the conrods to move. The engine number on the V5 is CE1234 presumably Cosworth Engineering.  Geoff also told me the car was CKD and traveled home in the boot of his car, whereas the VIN is KLD not KLDC; however to have the "C" it seems 100% of it must have been supplied by CC and in this case the engine, while being the BDR was not.

I found Bdx history here: https://en.wikipedia.org/wiki/Cosworth scroll down 6 pages to find BDA Series

Long time since I have updated this, and the following is from a thread I want recorded in here. First of all my opening post was looking for Dellorto Carburettor owners and went like this:

Dellorto DHLA Carburettors - discuss / tune /fettle?

I am busy tuning and fettling my twin Dellorto DHLA 45s doing things like Balancing with Carbtune Pro, fixing float levels and such like. My current exploration is how to fix my accelerator pumps which seem to be inoperative, one leaks (both barrels) and I suspect the 5mm gap at the end of the push rod is "missing", but that looks like I may have to remove the carbs from the car to fix and if removed to service the pump mechanisms (i.e. x 2). 

Purpose of my post here is to see if anyone else is interested in these sorts of things? Or even has experience of same. All first time for me. My carbs have been refurbished, but this was 9 years ago and only brought in to use relatively recently (a year maybe).

So ball bearings "stuck" are possible etc. My sources of reference are google, many web sites, youtube  and the book 3rd edition of SpeedPro "How to Build & Power tune Weber & Dellorto ..... DHLA Catburettors". I can't find any version of the Dellorto Tech book even in pdf anywhere. I also have contact with "my" carb refurbisher who seems to remember me. My previous owner/builder (r.i.p. 2018 age 90) assured me in about 2003 the jetting is perfect so I have no intention of changing any jets. Sounds like main jet "34" is ideal for my 1987 1700 BDR on standard 169bhp.

The Speedpro book is hard work because it combines both Weber and Dellorto in the same texts  - and avoids discussion of setting the length of the accelerator pump drive pole saying " do not touch".

So, anyone like to play this game? Sandpit now open.

(Do we have an index of all Dellorto DHLA chat on here? Answer is no not really.)

The carb balancing has also greatly improved the overheating problem as they were very (very) un balanced.

when I was asked :

"DHLAs - thats an unusual fitment - factory fit or later modification? "

and that lead me along the following path:

That's an interesting question. As far as I know it was included in the self-build from a CKD Kit. (Completely Knocked Down). Our most excellent archivist recently found my car's Purchase order; I'll have a look. So, no sign of the engine which he told me he bought direct from Cosworth with some mods he wanted. (I am since told buying from Cosworth direct was not possible; maybe an engine builder who was trading as if Cosworth.. or whatever.) The Dellortos were on the car and he spoke as if they had always been there from the start. 

I found the CC Pro Forma invoice, but engine not included, though of great interest to me in my provenance search, sold as a "BDR" and even with the "HPC Course", but not VIN recorded as an HPC because (a) not factory built and (b) engine not supplied by CC.

The 1987 BDR basic spec, I see Weber 45s which explains why my Dellortos are 45s when these days I am told these are "too big". Reading the book above says the Dellortos have a slight edge over Webers in terms of tunability at that time, and my builder told me he spent years tweaking jets so presumably he enjoyed and chose this choice as it were.

CONCLUSION

 There is no or very little Dellorto chat on BC; because the factory supplied Webers for both factory and kit builds. 

That thread is/was here

https://www.caterhamlotus7.club/forum/techtalk/dellorto-dhla-carburettors-discuss-tune-fettle#comment-2427980