Bulitpruf has used the stronger Chrysler 10/12 gear design since our introduction of our Pro Mod 4.5 hp starter over two years ago. By using the Chrysler 10/12 pitch gear, the teeth are 40% stronger then the Chevy 12/14 pitch gear. Up to now standard Hitachi type starters used the Chevy standard pitch. Even with our Bulitpruf starters breaking ring gear teeth still occasionally occurred. But now by using our 8/139 up grade even standard starters can eliminate stripping teeth off ring gears as is common today .
JW Performance now makes our 139 tooth Chrylser ring geared Chevy flexplates. We can offer this heavy duty design to complement any regular Hitachi type starters plus our line of Bulitpruf starters. Our 8 tooth pinion makes this upgrade easy to install. The upgrade only needs two parts, the pinion and the flexplate. With the 8 tooth pinion a 24 volt system is not necessary as with our competitor's design. The 8/139 ratio is so close (7%) to the regular 9/168 ratio that the starter doesn't know the difference. The 8/139 upgrade also uses the standard Chevy starter mounting block. We make the 8 tooth pinion in 3 versions, a standard gear for any Hitachi type starter, bulitpruf 1 & bulitpruf 2 for our line of starters Bulitpruf 1&2 gears are 9310 material. The Flexplate is the standard size & is neutral balance and sfi approved. An added benefit is the Chrysler ring gear has the teeth chamfered for better starter engagement. Next time you break a starter gear try our 8/139 upgrade. Its better, easier and cheaper than any thing out there. Better yet upgrade now BEFORE you break. Because they always seem to break going to the finals.
A word about gear teeth. The teeth on the 139 tooth flexplate have been described as Chrysler, 10 pitch, 10 degree, just to name a few. Gear teeth are generally described by its diametral pitch or DP or just Pitch. Pitch in this use is just the thickness of the tooth at its measuring point (about mid point of the tooth). The 139 tooth is .1571 thick. The 168 tooth (Chevy) is .1309 thick. There really is no Chrysler tooth or a Chevy tooth, we only use those names because that's what they are associated with. Gear design is complicated and pinion and ring gear design is very complicated because of the amount of gear reduction used. Its just too much reduction for two gears to do and mesh properly. So the engineers took bits and pieces from different designs to make it work, sort of. The standard Chevy is a 12/14 stub tooth design. First they shortened the tooth. Then they took some design features of a 12 pitch gear and combined it with some 14 pitch gear features. A standard Chrysler is 10/12 stub tooth design. Again they mixed and matched to make it work. Some foreign cars use a straight 10 pitch metric gear. These are the gears used on Hitachi and Denso starters for other than GM & Ford applications. They are close so they work well enough. Actually all pinions and ring gears are only close. So our 139 tooth ring gear is a 10/12 pitch tooth or a10 pitch or a Chrylser tooth and a 168 tooth is a 12/14 pitch or 14 pitch or a 12 pitch or just Chevy. We will try to use 10/12 pitch and 12/14 pitch, but sometimes its just easier to use Chevy and Chrylser.
A word on 12/24 volt systems. The heavy duty truck industry had used them for decades, but they couldn't wait to get rid of them. Ask any truck mechanic about series/parallel systems and see what they say. Ask about trouble shooting. Before you buy a 12/24 volt system look at the wiring diagram. You will know why the trucking industry is happy that this system is history. We can start just about anything with a Hitachi 3hp starter on 12 or 16 volts. For the extreme our ProMod starter. How about 505 rpm on a 526 blown alky ProMod engine with 16 volts. This was measured with a RacePack system. Call us, we can get you started , keep it simple and for a lot less money.