Triumph Repair: Triumph Spitfire Starter motor, moss motors, gear teeth

Question
Hi Howard.

My starter motor is in a bad way and im after a new/reconditioned one. However, im a bit confused by the type of starter i need and in particular the number of teeth on the pinion.  My existing starter has 10 teeth (on a 5 inch hole to hole mounting plate) but apparently im told all Spitfires have starters with 9 teeth. My existing starter is a Lucas M35J. Do you think someone has changed the pinion in the past? Does it matter that much if a fit a 10 tooth or 9 tooth starter? The teeth on my existing starter are in reasonable condition. My Spitfire is a 1977 1500.  Any help gratefully received. Thanks, Tony

Answer
Hi Tony,

Every thing I can find on it says it is suppose to be the M35J that you have and the Lucas part number is 25149 as original equipment. I did not find any information on any of the pinion gear teeth numbers. It is possible to have different numbers of teeth on a pinion gear with the same flywheel ring gear. The manufacture just changes the shape of the teeth but keep the same diameter. Some transmissions do that to have different gear ratios by only changing one of two meshing gears. I probably changed several starter motors when I worked for the Dealerships but that was many years ago and I don't remember any options on teeth number.

You should measure the diameter of both the 9 an 10 tooth gears to see that they are the same OD. You might contact Moss Motors as they are very good with details like that and they can check it against what they sell as they have new and reman starters for the Spitfire.

Howard