Lotus 23B Replica by Barry Leitch

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The following pictures are of the Lotus Twin Cam I bought from Bob Homewood at Bob Homewood Motorsport . The engine came from an Escort Twin Cam. I wanted to power the car with a Lotus Twin Cam as the Lotus Twin Cam had its first competition outing in a Lotus 23B in the hands of Jim Clark at the Nurburgring. The car lead for the openning laps untill the exhaust cracked The escaping exhaust gasses affected Clark causing him the crash the car. Not to worry a point had been made. The Bob Homewood engine is in very good condition and will, when assembled make for a very good powerful engine. I have decided however to use it as a base for the Escort Twin Cam instead as I have been fortunate in locating enough parts to build another Lotus Twin Cam. This engine will be based around an early die cast Lotus Twin Cam head that I bought ffor a very good price. The reason for this is that the head is very 'period' for the 23B car. Also I have managed to locate a number of the neccessary parts to complete the engine. I sourced a second hand set of good used 0.030" oversize Lotus pistons, used early style Lotus cam cover, full set of good used valve gear  - Oversized inlets (1.625") and oversized exhausts (1.375"). Having a 1500 block spare from an earlier purchase meant that the basis for a good club type engine existed. The current plan for the engine is as follows: Head: The fist step was to verify the condition of the head. It was hardness tested and leak tested. These tests revealed that the head was in surprisingly good condition for its age. Once this was established the decission was made to machine the ports and seats to suit the larger valves. Valve seats are to be fully radiused and machined at a consistent height. Worn tappet sleeves are to be bored to accept a set of shortened steel Alfa Romeo cam followers. Alfa followers are 35mm, Lotus are imperial 1.375" (34.925m) 0.075mm smaller. Cam bearing caps and journals are to be line bored as I have fitted a new set of cam caps as the originals were missing. There is other remedial machining required as well - such as damaged spark plug threads, facing the head etc. Block: Precrossflow 1500 block. This has been modifed extensively, oil ways opened out - some blanked off, square 711M main bearing caps fitted and line bored. The conrods are 125E Lotus 'C' type rods - shotpeened and balanced with ARP rod bolts. Crank is a light weight late model Datsun L16 steel crank - modifed by myself and ground to Ford sizes (see Datsun Steel Crank Modification Page). Flywheel is a 4Kg Martin Lucas special that is set up for a Tilton race clutch. Front pulley is a Burtons supplied Steel item as is the crank sprocket. All rotating parts will be balanced. I will post pictures once I get all the parts back from the various machinists used.

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