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Early Lotus Seven identification - plates, chassis numbers, frame numbers, and engine numbers


SENC
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The 1962 Seven Project on BAT (https://bringatrailer.com/listing/1962-lotus-seven-4/) has raised a discussion about "official" vs repro or even counterfeit ID plates.  To help those who might consider buying an early Lotus Seven one day, I thought it might be useful to gather information on the topic here.  As absolute facts can often be hard to establish with Lotus, I'd like this to be a thread to share not just what is "known" but also what is speculated, rumor, and even wives tale.  Perhaps enough information can be gathered in 1 place to at least assist in discernment.

 

It doesn't need to be said here of all places, I know, but neither a plate nor numbers, nor age, nor manufacturer have any impact on the potential fun of the Seven - this isn't a thread about value in any sense.  It is only intended for discussion  and discourse about identification of early Sevens as it relates to their numbers and chassis plates.

 

To get started, I'll share a picture of my chassis plate.  The first picture is circa 2008, I don't know that I have an earlier picture.   The second is after a little light cleanup (light because any more effort and only the stamping will be left!) - added only because resolution is likely better than the earlier photo found on the wayback machine.  I have great history on this car back to its original owner, so suspect this to be the original plate, but not sure there is really a way to tell for certain.  The Lotus Seven Registry website suggests the numbers could be stamped, scratched, or etched - but I've heard otherwise, too.

 

 

7circa2008-8.jpg

20200104_104140.jpg

 

And, for reference in case the BAT auction pics are one day unavailable, the picture of the plate for the vehicle listed.

 

1962_lotus_seven_163413052458a68d86721c769a082CBD3E-F236-4CB0-8B39-647BF9137674-scaled.jpeg

Edited by SENC
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I don't think the auction should be pulled. It seems to me the seller is being pretty open about what he does and does not know about the car. He seemed to believe the plate was legit. The comments of experienced Lotus people taught him otherwise, which is one thing I really like about BAT auctions.

 

Joe

eatonhong on BAT

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@eatonhong  Welcome to USA7s!  Well said!  I agree.  It is fully disclosed.  There is a title so that legitimizes its existence as a vehicle but does not provide any legitimacy to it being a genuine Lotus 7.  Legally you have all the elements to make a fair sale as the value it sells for will reflect the prevailing views of authenticity.  

 

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3 hours ago, JohnCh said:

Great idea, and although I have no knowledge to share, I want to plant a seed that this thread could form the basis for an addition to the Articles section of the forum.

 

-John

Good idea - and if enough input on this perhaps a subsequent thread on other ways to identify cars and bits by era and maker.

 

And I agree with @eatonhong and @Croc completely.

Edited by SENC
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Great start on a very interesting topic. Just for fun, this week I visited the dealer who has the  1962 car completely apart (as accurately shown in the video). The circumstance is very much like my 1959 series 1 Lotus #475 was in 6-7 years ago. After shipping it from Southampton UK I had sandblasted the frame, reinforced the front of the frame following SCCA specs for the old D production class where Super 7s used to run, added a roll cage and then it sat for 20+ years while I was too busy with family and work to get much done or go racing again. But I did collect various parts since it originally was built with a 1300 Alfa twincam motor and I have all the original Lotus receipts from 1959 and much more on MOT, owner(s) history etc.  So the 1962 in Lancaster , PA car certainly reminded me of where I was before a couple thousand hours of fabricating/fitting/building and then installing a 1500 pre-crossflow Ford built fairly close to Cosworth practice. The 1962 frame has lots of aspects that must have been specified by the same engineers that did my 1959 and looks genuine to me, but of course it has all the series 2 differences to account for steering location and rear suspension differences.  I looked at the number plate on the crossmember at the brake/clutch assembly mounting area but am not an expert on that (series 1 originally had pedals hinged from a bottom crossmember). It does appear that some previous owner felt the need to add some reinforcing tubes in the lower engine compartment and up at the front suspension area ( around the radiator) that I think are not original series 2 practice but a good idea ( the series 1 had a stressed aluminium floor pan all the way from the very back, up to around the engine so very different). The 1500 non-crossflow has the correct numbers ( 6015 on the block) just like mine ( so a mid 1960s type with the good 5 main bearing set-up). The dual Weber set-up is there but looks pretty old and needs cleaning/ ? rebuild ( like mine when I got it from an ex-racer). I did not notice an aluminium driveshaft tunnel ( which is structural in a 7) but was not really looking for it and the rear aluminium bodywork is missing but can be fabricated from 3003T16 ( ask me how I know). I look forward to seeing more inputs on this topic as 7s of all ages are great fun in many ways.

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Some have said the original plates on S2s are the ones from Lotus Components, like this example from a 62 S2 that I found on an auction site.  Has anyone seen or found anything definitive in this regard?

 

I know Elites and Elans of the same era had plates similar to mine above, and some had plates like this - so my suspicion is that they were likely both used on Sevens, as well.

 

Some have also said the originals were all inscribed, not stamped.  I've read somewhere (but can't find it now) that early on (for Elites and Elans, at least), the plates were attached to the body at the start and so couldn't be stamped without damaging the fiberglass, but that the practice later changed to stamping them before afixing to the body.  Makes sense - but does anyone know if true?

 

 

1962-Lotus-Super-Seven-Cosworth-Series-2_plate.jpg

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I may not be able to help much on the proper plate aspect. My series 1  No.475  was from 7 Tottenham Lane, Hornsey 29 April, 1959 which was a bit before the factory moved. The receipt is from Lotus Engineering Co, Ltd to R. G. Stern in Sydenham, London. But it changed hands over 5 times before I found it in Southampton. I doubt anyone would try to stamp a plate already attached to a 7 given how thin the aluminium is on the cowling. probably better to identify a real 7 by noting details on the spaceframe and where the steering rack attaches. Mine has the rack in the proper place of course but apparently the first few 7s had a box. I had picked up a box with steering shaft attached somewhere years ago ( and various other bits) but I do not recall why. Anyone interested is welcome to visit, like I did with Larry, very early in my project to be sure all was right.

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6 hours ago, Christopher smith said:

probably better to identify a real 7 by noting details on the spaceframe and where the steering rack attaches. 

I think this is right on - the plate itself is only 1 of several important factors in determining "authenticity", and the frame is the next good place to discuss.  I started with the plate mainly because it is the most obvious and most discussed, and also easiest to replicate - so my goal there was to see if we could establish any obvious parameters that might help someone establish that a plate may be real or replacement (or fake).  I'll post up some frame pictures and observations later, but want to reiterate what someone has already said in one thread or another here - that we are fortunate that there is a Lotus 7 Registry and a real expert there in John Watson who can help owners evaluate what they have (or are considering buying).  He and the (limited) factory logs are the best source - but it would be nice to gather as much general intel and knowledge as we can.

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Several sources indicate the frame number is located in 1 of 2 places in S1-S3 Lotus.  S1s and some S2s will have a metal plate with the number stamped on it welded to the frame just in front of the passenger seat.  If someone has a picture of one they can add, that would be helpful.  At some point (anyone know when?), the practice changed and the rest of the S2s and then S3s had the number stamped directly in the frame beside the brake/clutch master cylinder mount.  I've added a couple pictures of these later stampings, and a drawing with the locations circled.

 

Note this is a different number than the chassis number or VIN, and was frequently (always?) recorded with the chassis number in Lotus records, so together they are very helpful for confirming identification.

7drawing.PNG

1962-Lotus-Super-Seven-Cosworth-Series-2_frame.jpg

7circa2017framenumber.jpg

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@SENC Henry - Do you know when Arch Motors started stamping its own identifying number on the chassis?  I assume it came on in the 1960s when replacement chassis started being needed after race day accidents?  

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@croc - to my knowledge Progress and then Arch stamped their frames from the start.  There may have been a company in between, too.  I don't know exactly when Arch started making the frames for the Seven, but at some point in the S2 range.  A total guess, but the transition may be marked by the change in stamping location (frame at base of passenger seat to frame at master cylinders).  The #B1431 frame above is from a 1962 - so likely earlier than 62?  I'll check some of the resource books I have over the weekend.

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From simple sevens: http://www.simplesevens.org/anglocanadian/angloParts.htm

 

There were two factory approved constructors of the mild steel Series 2 and 3 chassis, Arch Motors, and Universal Radiator. Arch Motors preceded their chassis number with the letters A/M. Universal Radiator used the letter 'B' (possibly followed by an 'L' if the chassis was left hand drive) with four numerals for the chassis number. This letter/number combination was normally stamped on the angular steel bracket that held the front mounting of the master cylinder bracket. It should not be confused with the actual vehicle serial number (V.I.N.) such as SB XXXX or LSBXXXX.

 

For what it's worth, My July 1963 Car (SB1762) has a B stamped infront of the frame number on the master cylinder mount.

 

Here is my Lotus Components Plate. The only other person that knows the frame number is John Watson. I believe that the best way to preserve the integrity of these cars is to keep the frame number private so John can use it as verification. 

photo_4.JPG

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That is a good find, @TheDingo8MyBaby, thanks!  As many times as I've been to and through the simplesevens site, I never found that page.  Some good information.  So, that would place the Arch Motors start with the chassis later - my 65 also has a B.  I understand your point about preserving some identifying information - on the flip side, in this day and age, I've wondered if full transparency for all to see doesn't provide as much protection (why risk a counterfeit of something that is publicly documented?).  That wondering notwithstanding, I have a tendency to post/publish slightly altered pictures (cropped, zoomed, etc.) so that if one ever got used for something counterfeit I'd have the original basis.  Silly and sad we have to go through this.  Again, nice find.

Edited by SENC
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  • 1 month later...

@Mr Mark's new car post reminded me to finish this thread by adding engine number information.  I don't have any personal knowledge of the coventry climax or bmc a engines that were used in early Lotus Sevens - please contribute if you do!

 

The Kent Ford blocks, from pre-crossflow to crossflow to twink had the engine number stamped just above the right hand side motor mount.  Years of paint and crud may make this hard to read - a lead rubbing may reveal it in that case, below is a picture of mine that revealed most, a second effort after cleaning confirmed the rest matched my records.

 

 

Inked20211009_161433.jpg

IMG_20211025_172013.jpg

Edited by SENC
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  • 2 months later...

Hi all,

 

Just want to chime in with my own question. My father has what I presume to be either an S2 or S3.

I am trying to locate the VIN and in the process had a look at the chassis plate, which peculiarly states the Unit No without any letters - and this number is larger than 2649 (which is the upper # for S3's I'm told). How is this possible? Could I be dealing with an S4? It is clearly a Lotus though. 

 

The chassis plate also says LOTUS Norwich, England - which is different to several of the chassis plates I've seen above in this thread.

 

Help much appreciated!

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6 hours ago, chuet said:

Hi all,

 

Just want to chime in with my own question. My father has what I presume to be either an S2 or S3.

I am trying to locate the VIN and in the process had a look at the chassis plate, which peculiarly states the Unit No without any letters - and this number is larger than 2649 (which is the upper # for S3's I'm told). How is this possible? Could I be dealing with an S4? It is clearly a Lotus though. 

 

The chassis plate also says LOTUS Norwich, England - which is different to several of the chassis plates I've seen above in this thread.

 

Help much appreciated!

Later S2s and S3s were built at Hethel/Norwich.  I would expect the frame number to be stamped on the frame near the master cylinder mount (assuming right hand drive).  Post some pictures of the car and we may be able to help with ID, but the best way to be certain is to reach out to John Watson with the details of the car that you know.  You can find his contact information at the Lotus Seven Registry website. 

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40 minutes ago, SENC said:

Later S2s and S3s were built at Hethel/Norwich.  I would expect the frame number to be stamped on the frame near the master cylinder mount (assuming right hand drive).  Post some pictures of the car and we may be able to help with ID, but the best way to be certain is to reach out to John Watson with the details of the car that you know.  You can find his contact information at the Lotus Seven Registry website. 

 

Thanks for the help. Posted the couple of pictures I had available with me. It is a left-hand drive car.

From the unit number I have from the chassis plate, I would expect it to be an S4, but I read that very few Lotus ones were produced before Caterham stepped-in. Does anyone know what was the last numbered Lotus S4 was?

 

Also, am I right in assuming that the frame number and chassis number should match?

I'll reach out to John Watson once I have more info, am not with the car at the moment so can't investigate further myself yet. Will keep you posted.

 

 

IMG-7334.jpg

IMG-7333.jpg

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