Expert: Dan Liddy - 7/22/2011

Question
I find difficulty starting my first ever self-built racing engine, to be installed into a British Mini 1275 GT. The engine was built strictly in accordance to a service manual and the compression is 12:1. The problem is that the starter does not turn well with the standard starter motor and a 12 volt battery. However it turns well and ignites the engine when I temporarily connect (in desperation) another 12 volt battery in series, giving 24 volts for starting. I have check the electrical for good earthing but the problem persists. Do I have to include an electrical relay in the wiring system, and how is it done. Can I convert the standard starter motor into a hi-torque starter motor and how is it done.

Answer
I'm going to forward your question to a friend with years of experience with Mini's and Sprites.
My first answer is to change to a Tilton Hi Torque starter. The starter originated from a Datsun 280 ZX in the 1981 model. It's a gear reduction starter that will turn a 366 Chevy small block with 12:1 compression and 700 horsepower.

Of course, it will have to be adapted to the Mini block but any machinist can do that.

While I wait for a response from my friend, I suggest you check for proper voltage at the starter.
Check voltage at the battery ,it should be 12.5- - check again at the starter solenoid , You should still get a reading of  12.1 or so. Then disconnect the ignition, and have someone energize the starter while you check the voltage at the starter again. the meter should read over 10 volts with the starter running. You may have to run heavier cable to correct the voltage drop, it's frequently a problem even over short runs.

So give me a day or two to consult my pal, and I'll send a follow-up answer

Good luck !!

Dan Liddy
Sarasota, Florida, USA