Engines...some go bang and some just go!

When I bought Blossom, I sought out a car with a Ford "Kent" Crossflow motor. This was the basic motor that was used in the Lotus 7 S3 and the Caterham S3. I wanted a car that was as close as possible to a real 7, although I was under no illusion that I was getting anything other than a replica. The Ford engine was great. It sounded superb, it banged and popped on the over-run so that it sounds like Beelzebub's own Rice Crispies. The two Weber sidies gurgled away and the car felt quick.

It felt quick right up until the time I first took it racing, at which point, with other 7's running Toyota 4AGE engines, Ford Zetecs and Mazda rotaries I felt like the guy who arrives at a gunfight armed with a decorative teaspoon. And that was after I had had the engine refreshed with new pistons and rings. Worse yet, after not many race meetings, the engine lunched the big end bearings and cylinder walls too. Ford x-flow motors are now regarded as classic motors, and spares are either in short supply or expensive or both, and repairing Blossom's Ford motor would have cost a fair chunk of cash.

So I decided to bite the bullet, and opted for a Toyota 4AGE 20V engine. Twenty valves! That's an awful lot of breathing going on. That was more like it! The 4AGE has been described as a BDA with metric fasteners. The Cosworth BDA was basically a 1600cc Ford Kent block with a twin cam Cosworth head. The 4AGE, whether in 16 or 20 valve form is a superb motor, and well suited for a 7. It's tough as nails and will happily rev to 8,000 rpm forever. They can be revved beyond 8,000 rpm, but longevity suffers.

The first time I drove the car with the 4AGE installed was manic. Ap to 4,000 rpm the car feels quick, beyond that it gets very noisy - in a good way - and it's like entering warp speed. Things on the horizon get very big, very fast. It's fun!

With the new engine my lap times came down a notch, but still I wasn't satisfied. The guys that I race against were not getting away from me through the twisties, but on the straights they just blasted away from me like I was lost and looking for signposts. When it rains I can run with the rest of my class, and can even gain a class placing, but in the dry I am driven to drink.

The most basic question in motor racing is not "how fast do you want to go?" but "how fast can you afford to go?". In my case, not that fast, but I did want to go faster. So I removed the cylinder head and sent it off for some fettling. Gas flowing and a cam grind to 280 spec, with a vernier gear for the exhaust cam to allow for precise cam timing. The inlet cam is variably timed, so there isn't really anything that can be done if one wants to retain the variable valve timing.

The cylinder head went back on yesterday, as I write this, and tomorrow we are off to the Dyno Man to have the engine management re-mapped to take advantage of the new cams. It certainly sounds meaty now, with a slightly lumpy "hot cam" idle. Dyno tune tomorrow, race next weekend. It's all rather exciting; excuse me, I need to go and lie down in a darkened room now.

Introduction - Meet Blossom

Blossom is a "20 foot" replica of a Lotus 7 S3. From a distance of 20 feet away, you'd be hard pressed to tell whether she is a real Lotus or not.

Why Blossom? It's just a very small pun on the flowery nature of the Lotus name. I don't usually refer to the car as a Lotus ('cause it's not), calling it a Lotus replica sounds too fussy (although accurate), and with the time that I have spent with the car, it just sort of acquired a name.

I bought the car about 18 months ago, largely to use as a race car. Although it is a race car, it is fully road legal, and I drive to and from race meetings. I don't have the space for a trailer and I don't own a car suitable to tow a trailer so road legal Blossom remains. When I bought the car I sought out a Ford x-flow powered example because I thought that would be closest to a genuine Lotus (or Caterham) car.

But after six months or so when the Ford motor lunched itself, I decided that fixing it would be more expensive than it is worth and I opted to install a Toyota 4AGE 20 valve "Silvertop" motor. After some initial teething troubles, this has seemed to be an excellent choice of motor. Cheap, freely available and happy to rev to the skies all day.

Blossom sports "clamshell" fenders, where most 7's these days have cycle fenders. Cycle fenders may make the car slightly faster but I just love the old-fashioned look of the clamshells. Having a car that looks old-fashioned, but out-accelerates and out-corners most cars just adds to the fun. To reduce wind resistance and increase that old-fashioned look I ditched the full screen and replaced it with a pair of Brooklands aeroscreens. As a bonus, the Brooklands screens give less turbulence than the full screen used to create.