2007 examination of Lotus 11 - #153

                                                                                                                notes by Jay Sloane


This web-page is intended for private viewing by a selected audience.  The points and opinions expressed here are open for review and discussion.

Lotus Eleven , chassis #153 is now in Belgium after spending nearly 50 years in Texas, USA.  It is almost certainly the prototype Lotus Eleven, called P-7 at the works, different in many ways from production models.  Fortunately most of the unique details of this car have survived the years and provide us with things to talk about today. 



You may recall while we were first planning an inspection of this car, Russ Hoenig sent a drawing he did years ago of the erasure marks from an original Lotus chassis drawing.  The drawing showed traces of two prior positions of the front tube, in front of the radiator.  This detail provided our first question.

On #153 today the front tube is straight, rather than curved at the ends, but it's also obvious the tube is welded behind where a previous one had been.  In this photo we can see what the erasure marks had been about.  The tube had originally been an inch farther out, then was cut away and replaced with another behind the intersection of the two support tubes.   After examining the bonnet for this car, and the very normal hinge and subframe that surrounds the air inlet, I'd guess that a mistake had been made where the one-inch bonnet / cowl overlap hadn't been taken into account in frame or body dimensions.  The fastest, easiest way to remedy the gap was to shorten the chassis by moving the front tube.  Also, the ease of bonnet fabrication & fit may have been the reason why later Elevens have a curved front tube. Also, the radiator probably would not have fit between (erased) angled support tubes shown in the drawing. 

The mod notes at the bottom of the S-1 chassis drawing mention changes to the steering mount. Chassis #153 has a 1/2" diameter rear mount tube plus the fabricated pieces seen here.  But would Lotus have shipped a car with these cobbled parts? At the pedal box there is evidence of fitting & re-fitting the steering column.  It has an alloy patch where alternate column positions were tried out.  It wasn't easy to clear the engine and still have some room for pedals!



There is a question whether the ugly, heavy steel expansion tank is the original one.  Would Lotus have passed this off on a buyer? Chassis mod note #9 from 1-22-56 describes how the tubes for it were changed to 5/16" diam.  Chassis #153 has 3/8" diameter tubes surrounded by rubber hose to help support the tank.  

Chassis #153 also has the channel for the brake fluid reservoir, the bolt for the front brake pipe T-junction and the holes to help secure the brake lines. Detail 'Y', the little bracket for the rear brake line, might have been there once, but is missing today.

The firewall has a trace of the second engine-bay diagonal (not shown here) and there is more trace weld-metal where it was located at the front.  In this photo we see a short diagonal tube from the opposite side of the firewall to the scuttle brace at the solenoid.  Has anyone seen one of these extra diagonals before?  The welds looked original to me.

Perhaps after the engine bay diagonal was removed this short diagonal brace served no structural purpose and was then omitted from future cars.  

Visible on the sponson are traces of the second fuel tank retaining straps. The rivet holes for these remain.

Here the left-side fuel tank has been removed to reveal the channel for what was intended to be an enclosed silencer.  This was one piece with the sponson and may have been too complicated to make for production. 

Throughout the inner panels there are many other differences with production Elevens, as details were perfected and presumably simpler fabrication methods worked out.

Most of the chassis appears to be in very good shape and most  -- if not all -- of the panels are original.

However, the seatback is a mess, with square tubing from Texas and a big steel plate added to provide a mount for the SCCA roll bar.  This area shows abuse from people who weren't born engineers.  The diagonal control arm pivot is almost unsupported.  The square tubes do not appear to even follow the pattern of the original structure.

Not visible here are some air vents for the brakes, added to the undertray but without any ducts up to the rotors.  

At the seatback sides are unused pivot holes for a curved location arm.

Another question is whether the deDion tube is original Lotus.  It appears of smaller diameter than normal and seems to be a heavier gauge, welded to a lower standard than the chassis.  (I wish I'd checked underneath for any trace of a bracket for the curved arm. ) Was this a prototype deDion tube on P7? 

The battery on this car had been moved (in Texas) to a location in the footwell next to the fuel tank.

This photo is one Tony Clark sent to Russ Hoenig in the mid-1970s. The car hasn't changed at all in that time.


Today the car has FWA #6960 and an MGA gearbox (neither is original) with the transmission tunnel cut to allow the box to fit.  The owner, Erik Staes and the restorer, Marc Widar want to be sure of what belongs in the prototype and what doesn't.  Thank goodness nothing has been changed or removed (except years ago, in Texas) that would help us identify it for what it is.   It is without a doubt the most important and interesting Eleven that I've ever seen.

Chassis #153 compares to the first ten mod notes on the factory drawing as follows:

4) 21/11/55     Redrawn

5) 28/11/55      BTM SIDE TUBES MADE SQ..  (square on #153)

DIFF. PICKUP MOVED REAR.  (frame currently modified on #153, original unknown)

RADIUS ARM TUBES ADDED.  (present but unused on #153)


FRONT FRAME MOD. (could be the radiator support tube changes on the early plans)

MAIN SEATBACK TUBE WAS RD. (square on #153)

6) 18/12/55      RACK & PINION MTG. CHGD. (but from what to what?)



SEAT BACK RISE WAS 1 NOW 1 . (unsure if this tube is original, not measured)

SCUTTLE TUBE HT WAS 21 (not measured)


ENGINE MTG. TO BE ADDED BY DIMEN D (present on #153)

7) 1/1/56          FRONT TUBE MOVED AFT TO 18. (#153 crudely updated to this)

                        RACK & PINION REAR TUBE MOVED AFT (unsure, not measured)

                        ANGLE ON CHANNEL WAS 2 (unsure, not measured)

8) 14/1/56        CUT/OUT AT X ALTERED (unsure, not observed)

TUNNEL MTG NOW 7 5/8 WAS 8 (8 on #153)

TOP NEAR SIDE DIAGONAL REMOVED (also removed from #153)

OFFSIDE MOVED IN .  (unsure, not certain of measurement)


FRONT TUBE WAS STRAIGHT (straight on #153)

9) 22/1/56         5/16 TUBES ADDED TO TOP DIAGONAL. (changed, 3/8" on #153)

                        BOLT ADDED TO FRONT FRAME. (present on #153)

                        HOLES ADDED (present on #153)

                        F CHANNEL ADDED TO TOP FRAME (present on #153)

                        6 1/8 DIMEN TO RACK & PINION FRAME WAS 5 5/8 (not measured)

                        DETAIL Y ADDED (this area is modified on #153, original status unknown)

10) 6/2/56        TUBES FOR LOWER RADIUS ARMS DELETED. (present on #153)

                        LOWER REAR FRAME TUBE LOWERED. (unsure)

                        HOLES FOR OIL FILTER MTG ADDED (present on #153)

& ADDED MTG FOR OIL PRESSURE (present on #153)

FRONT TUBE WIDTH WAS 35 (closer to 36 on #153)

Much of the uncertainty noted above is a result of not knowing what the earlier (pre-revision 4) chassis plan looked like, and not enough tape measure. Victor (who first identified #153 for what it is in 1987) has plans to see the car soon and has plenty of details to check when he does. Perhaps this page of photos will help stimulate more discussion from those who worked on it when new.        Thanks -- Jay

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