introduction

1968 - 1972

1973 - 1974

1975 - 1977

1978 - 1984

1985 - 1989

1990 - 2000

2001 - 2003

conclusion

 

In 1973, the new, compact, powerful Mazda rotary engine was too alluring not to try, so out came the twincam. Wow! It took quite a bit of development before I was able to make the IDA Weber carb work, but it was worth it. Stories about these new engines sold magazines, so Road and Track did a June 1974 article about the car.

credit: Jake Grubb, Road and Track magazine, June 1974

Ira Emus, a Seven owner himself recalls meeting Jim about the time of the Rotary installation...

My first car was a Lotus 7 and I parked it in front of the house of a girl I was chasing who lived about 1/2 block from Jim. One day he stopped and said hello.

As far as I know, [Jim's Seven] is only famous because the number of times the rules have been changed to outlaw it. I was last in it right after the first Mazda engine went in, don't know how much I helped, but I was there watching during the whole transplant and its original twincam is now in my 7 [the twincam was the second engine to reside in Jim's Seven]. It used to be the car most likely to set TTOD at the Southern California slaloms back in the early seventies.

The hardest parts were quieting it down and getting a carb that would work in a corner. On one of the first outings we were sitting at a red light to make a left turn and we took off on the green and Jim nailed it after we got through the construction in the intersection. At about 80 having not shifted he realized that he'd started in third and the engine had so much torque he'd not noticed.

Jim is amazingly resourceful and I don't think anything ever really got in his way. I remember when he bought torches which made things go a lot faster and I remember the first time the engine started with no muffler and it was the loudest thing I'd ever heard in my life. One day after Jim decided to build nicer headers he made the steel plate that attached to the engine, cut the holes for the exhaust pipes and bolts that brazed the pipes in place. Not long later while driving somewhere the braze melted , the header pipes popped out and the car got really loud -- Rotary exhaust is a bit loud with no headers.

The clutch/flywheel assembly for the rotary weighs 10 lbs. while the stock assembly is over 50 lbs.
photos this page, credit: Jake Grubb, Road and Track magazine
.

Hanging it out in Santa Susana Canyon near the infamous Spahn Ranch where Charles Manson lived. Jake Grubb was doing the photos for R&T and he asked me to slow it down a bit because he was concerned I might "lose it" in the canyon.
photos credit: Jake Grubb, Road and Track magazine
 

back to simplesevens

back to People

next