Engine Rebuilds – Rebuilding a Lotus Twin Cam

The Ford Lotus Twin cam, the legendary high performance engine of the sixties era. The Mk1 Twin Cam was introduced as a test bed engine in the Mk1 Cortina in 1963 & followed by the Mk II which powered the

Mk II Lotus Cortina – the same engine that was also fitted to the 1968 Escort Twin Cam.

The lotus Cortina & the Twin Cam Escort were instant winners both on the track and in many, many rallies held throughout the world. It is often said that the sixties were the golden years of motor sport, and the firm of lotus and their highly competitive cars were held in high esteem. But the Lotus elan which was publicly released at the1962 Earls Court motor show was the sports car that set the motoring world alight, the elan established a reputation for rapid point to point motoring, as well racking up success after success on race circuits around the world. Lotus was quick to build on those success with the release of the lotus elan 26R, the racing version, which was based on the elan S2 model, only about one hundred 26Rs elans were produced by the factory.

The run of the mill four cylinder ford cast iron engine block provided the base on which the twin cam engine was built, the cylinder head was a Harry Mundy designed twin cam alloy head, which incorporated chain drive to the twin over head cams, which actuated the eight valves. The engine was normally aspirated and fed by ‘twin forty millimetre Weber carburettors, which are characterised by the distinct clucking sound they made when the throttle butterflies are opened.

But despite the high power output of this small four-cylinder engine there are two Achilles heals of this engine, the first being the reputation for water pump failure, which is mostly caused by the engine being left standing for long periods sans any coolant in the block, on the first crank of the engine the dry seal is ripped during the first turn over.

Many elan & escort owners have also upgraded from the original dynamo to a modern alternator for the electrical system, the high tension on the belt required to run the alternator places excessive side loads on the water pump which can lead to premature failure… the standard water pump replacement requires that the alloy twin cam cylinder head be first removed, this can lead to a very expensive mechanical repair for the non-practical twin cam owner

The best fix for this problem is to install the newer modular type water pump, making it far easier to remove and replace. The other problem with the twin cam lotus engine is the constant habit of the engine of losing oil pressure on tight right hand turns, many owners choose to ignore this problem at their own peril, lotus twin cam

drivers have been known to simply listen for the bearing rattles then’ back off, and wait for oil pressure to return…. if you hear bearing rattle, the engine is only a few seconds away from a potential engine blow up,

From a cold start, bearing rattle can be tolerated in an engine because it only lasts for one or two seconds while the engine is at idle., but it is an entirely different story when the engine is revving at four to seven thousand revs per minute where even a short oil starvation period can have a devastating effect on the engine bearings, bearing failure is not an if, but a matter of when the engine bearings seize on the crankshaft.

But You’ll Be Pleased to know there is A Fix – But there are really only two options;

1: If you are into circuit racing, then dry sump lubrication is a given, it can be expensive and time consuming to set up and to get it right, but most racers swear by dry sump lubrication.

2: Install A Gated Wet Sump Oil Control system.

It sounds technical but it is not, the gated sump system consists of designing and building a unique apparatus which is installed in the standard twin cam sump or oil pan, it is not expensive to build or difficult to fabricate, it is not complex, and most home mechanics would be capable of building the baffle if they enjoy fabricating with sheet metal, and they also understand how to do a small amount of brazing.

No one but you will ever know that there is a special anti surge oil control system installed in the sump of your twin cam lotus engine. But the difference is that with the gated baffle installed, you will be able take any given corner at high speed in your Ford escort, Lotus Cortina or lotus elan and not have the slightest worry about oil surge, the oil gauge will tell you that the correct oil pressure is being delivered to your legendary twin cam lotus engine, it’s about piece of mind and confidence with high performance motoring. Build it once, build it right, and you’ll have no problems.