Steelbro Super Seven Mk4

[EdWills]

Admin note: this thread was split from the following for sale thread.   https://usa7s.net/ips/topic/15452-1979-lotus-super-seven-mk4-twincam-steelbro-nz/

 

Although interesting information, it is more appropriate for a dedicated thread in the General section than it is within someone's for sale advertisement.

 

A Series 3 and Series 4 Hybrid?  Back end looks Series 3, front end Series 4.  This is similar to the combination of chassis parts used on the Lotus 7X Clubman race car. Never seen one advertised like this before, and no pictures of Steele Brothers producing a car like this using alumimium for the body panels.  Would be curious to see the chassis frame work. Interesting! W

Edited June 14 by JohnCh
Added admin note after thread split

[EdWills]

Just a P.S.  Forgot to add, that in my opinion only, this is what Lotus should have done with the Series 4.  Not so much fibreglass, and aluminium and frame from the Series 3 with the Series 3 SS additional tubing for strength.  This would then follow on from the 7X in appearance (although the 7X was heavily modified over the few years that it raced due to less than optimal frame design strength).  The one-off Series 4 Clubman used the Series 4 frame and some of the bodywork, but retained aluminium for the side panels the same as the car shown above.  Would also note that the aluminium body work on this car - around the dash - looks very well done.  If I was in the market for another Seven, this would be right up there on my wish list. Cheers W.

[Carz01]

This is certainly an interesting S4.  I have an early Steel Bro S4, TC BV, and based on the information I have, Steel Brothers sold S/N 3001 through 3043. The remaining chassis and components were assumed to be stock on hand or work in process when Steel Brothers sold the manufacturing rights. The S/N is not listed as a completed car at the time, so it looks like this chassis was constructed with aluminum body similar to the S3.

[EdWills]

Hi Carz..  Great info. - thank you.  I am guessing that Colin Chapman would not appreciate Steele Bro. messing about with a car that Lotus had authorized for construction (the Series 4/IV model only) by this company (although Steelbro did manage to slot in a Lotus 907 engine in some of the cars).  The only other Seven/7 to be authorized and constructed away from the Lotus factory was the Argentine Seven (Series 3 model).  This used Fiat engine and transmission parts, but not very many constructed.  Some time ago, I contacted the New Zealand Lotus Seven Club, and they may still hold the molds and jigs for the Steelbro 7 Series IV.  When Caterham bought the rights to the Seven from Lotus, Caterham commenced construction of the Series 4 until some of the specialized parts started to run out with outside contracted manufacturers deciding that small build numbers were unprofitable for them. That is when Messrs. Nearn and Wakefield decided to resurrect the Series 3.

 

Last incarnation of the 7X.  It is featured in the magazine shown in the photo.  The Series 3 rear end had been removed from the car and a later rear wing added.  There are more photos of the original 7X on the Lotus Seven Register by John Watson and also at anglocanadianlotus7.ca  The 7X was based on the Series 4 chassis with ally panels and some fibreglass as per the Series 3.  W.

Edited May 14 by EdWills

[IamScotticus]

Is that a Corvette diff?

Edited May 17 by IamScotticus

[EdWills]

Hi Scott.

No, it's a Lotus casting.  Same diff. as fitted to the Lotus Elan with Lotus Formula Ford uprights. W

[EdWills]

And the one-off Series 4 based Clubman Car at the 1971 London Racing Car Show. The fibreglass bodywork is stacked up nearby.

[EdWills]

On 5/14/2025 at 10:27 AM, EdWills said:

  The only other Seven/7 to be authorized and constructed away from the Lotus factory was the Argentine Seven (Series 3 model).  This used Fiat engine and transmission parts, but not very many constructed.  

I found a reference by the author of a Lotus Seven book that Lotus also authorized construction of the Series 3 in Spain.  

On 5/14/2025 at 10:27 AM, EdWills said: