The Europa Side - TC Engine Mods

By Don Nester
Chapman Report – November 1979

Three months ago I visited Twin Cam Enterprises (Note: TC Enterprises is now closed) to find out from the experts how to increase the number of horses which could be stabled within a Twin Cam. Although my mission was successful, the source of the best Twin Cam performance engine building has gone into retirement… to be blunt, Twin Cam Enterprises has gone out of business. It is hoped that Jan, Armand and Alec will find a way to put this back together in the future.

But on with the subject of this article… Making the Twin Cam perform. The 1600cc Lotus Twin Cam in stock form is in reality loafing with respect to its real potential. In my discussions with the experts of the presently extinct Twin Cam Enterprises (TCE), four stages were outlined for releasing the ponies which are couped up inside a Twin Cam. All stages are targeted for street driving and in no way render the engine too high strung to inhibit the normal street drivability of the engine. The performance stages may be summarized as follows:

Stage 0 (Stock) Gee that’s nice, these little cars are really pretty neat.
Stage 1 (minor mods) That’s great… But, I bet you have a tough time with a good Vette!
Stage 2 (1st level mods) I didn’t know that a little car like that could perform like that!
Stage 3 (2nd level mods) Wow! Is there anything that can catch this thing?
Stage 4 (3rd level mods) My God! Do you really think this thing belongs on the street?

Starting with Stage 0, a stock Europa is not a bad performer and very satisfying to the ego. In stock USA form the Twin Cam generates about 90 HP which is very reasonable for a car that weighs only 1650 lbs. Using your calculator, you will find out that with a 150 lb driver, that you have one HP per 20 lbs of car.

The Stage 1 modifications are the least expensive step for the addition of ponies to a Twin Cam and requires only desmogging it. Although the EPA (and the state of California) frowns on this practice, I have seen very few Twin Cams which have not had these modifications performed on the engine. (Ed 1997 note: With the passage of SB42, cars of model year 1973 or earlier will be smog exempt from Jan 1, 1998) These modifications require no internal surgery and consists of the following superficial changes:


  1. Remove crossover smog tubes and block off holes in intake manifold. Cost: $0
  2. Remove secondary throttle plates and shafts from smog manifold and then plug throttle shaft holes. Cost: $0.
  3. Change carburetor jets to B1Y (this is not easy since this jet is not imported into the US). Cost: $20.
  4. On the distributor, plug up vacuum retard, file centrifugal advance stop to allow 16 degrees advance, bolt vacuum advance plate to the fixed plate below it, and have the distributor recurved to pre-smog Elan specifications. Cost: $25.

The above changes will require about a day’s time and will add about 10 horses to the stable. With your handy dandy calculator, you will find that you have about 100 HP and that now each horse only has to lug 18 pounds of car.

The Stage 2 modifications require much more time and money, but yield much more in the way of performance. All the modifications which are required in Stage 1 are also required for this level of modification. Stage 2 mods require a complete engine rebuild and basically consists of stroking the engine to 1700cc. The following must be done for Stage 2 modifications:


  1. Replace the original crankshaft with a 1600 Pinto crankshaft. This has a slightly longer throw and will add about 100cc’s to the displacement. Cost: $250.
  2. Replace the original pistons with TRW forged pistons that have an offset pin height to compensate for the longer throw crankshaft. Cost: $240.
  3. Regrind cams to Piper 8FY2 specifications. Cost: $120
  4. Have engine blueprinted and balanced. Cost: $200.
  5. Add headers. Cost: $175.
  6. Reneedle carburetors. Cost: $2

Making these modifications will boost the horsepower to 120 HP and will require each horse to pull 15 pounds of car. When making these modifications it will be necessary to degree the cams. Also, be conservative with the compression ratio and do not exceed 9.5:1 (if you do, you will most probably have problems finding gasoline that will not knock). These modifications will also reduce your trip gas mileage to 34 and town to 22.

The Stage 3 modifications require the same changes as in Stage 2, but require the substitution of a Weber head for the Stromberg head. The trick here is finding the head. It is out of productions, so it can not be bought new. Formula B racing heads do not work well because their ports are too large (these are for full race cams and very large carburetors). The only option is to find a head from an old Elan, Lotus Cortina or Super 7. When you find it you will also find the cost is not cheap ($600-1200 and if you persuade the owner to part with it). After acquiring the head it will most probably have to be reworked for the bigger valves. These modifications may be summarized as follows:


  1. All Stage 2 bottom end modifications, cam regrind and headers. Cost: $985
  2. Weber Head. Cost: $1000
  3. Weber Carburetors (32mm chokes). Cost: $250.

These enhancements result in increasing the horsepower to 135 which decreases the weight that each horse tugs to 13.8 pounds. The gas mileage will drop to about 32 highway and to 20 in town.

The Stage 4 modifications require basically discarding your original Lotus Twin Cam and building a street version of the Cosworth BDA 4 valve engine to replace it. This will require the following:


  1. Ford Pinto 1600 short block. Cost: $500.
  2. BDA head with valve gear. Cost: $1200.
  3. Weber carburetors. Cost: $250.
  4. Piper 8FY2 cams. Cost: $300
  5. A set of Cosworth pistons. Cost: $500.
  6. A good set of headers. Cost: $175.
  7. Blueprint and balance engine. Cost: $200.
  8. Harden crankshaft. Cost: $160.

As you see, it costs to go fast. Expressed mathematically, performance is directly proportional to the number of rectangular dollars invested. The Stage 4 engine swap results in a very fast Europa which is also very suitable for street use. The horses will equal about 140, leaving only 12.8 pounds for each horse to yank forward. The gas mileage will drop to 18 in town and about 30 on the highway.

For the best results, the final engine adjustments must be made on a dyno. This allows the necessary controlled environment where final carburetor and distributor adjustments will be made to exactly match the modified engine (note: no two engines are identical).

In conclusion, if you want a fast Europa for a reasonable cost, Stage 2 is the only way to go. If you want the fastest Europa in town, the Cosworth BDA is the best solution.