In the quest for ultimate performance, the car crafter's perpetual search for horsepower is perhaps only paralleled by his infatuation with reducing weight. Aluminum blocks and heads really help, but more often, removing 25 pounds from five different places is the likely avenue to success. Starting in 1993, both GM and Ford began building more efficient starter motors that were also lighter and smaller, and these quickly became known as permanent magnet gear reduction (PMGR) starters. Before you fire up the gear reduction email onslaught, let's be clear that any good gearhead knows that gear reduction starters are not new. Most car guys know the distinctive whine of gear-reduction starters used in Chrysler products dating back to the early '60s. The difference with this new breed of gear reduction starters is the addition of permanent magnets that do not require bulky and heavy electrical field windings to increase the electric motor's output. Permanent magnets allow the starter to be significantly smaller, especially when compared with classic starters used in muscle cars from the '60s and '70s. Compactness is important with engine swaps or long-tube headers. The first Chrysler gear reduction starters used offset gears that added width. The advantage to late-model PMGR starters is the planetary gear-reduction system that multiplies torque while being entirely in line with the armature shaft. Planetary gear multiplication (similar to gear reduction in automatic transmissions) produces a major torque increase within a very small envelope. In discussing PMGR starters with Brady Basner at Powermaster, we learned that the only drawback with OE PMGR starters is that the gears are mostly plastic. This makes them susceptible to breakage should the engine kick back during cranking. Powermaster recommends using these starters on engines with less than a 10:1 compression ratio and preferably only on EFI engines. Powermaster offers one PMGR small-block Chevy starter that uses a steel planetary gear-reduction system that is more durable. The company is working on converting several other starters to metal planetary gears. In addition to the GM small-block and LS engine applications, Ford converted to PMGR starters in 1993 and later used them on 5.0L Ford engines. These would also make great swap material for older pushrod small-block Fords. Description PN Source Price Tuff Stuff PMGR starter, SBC 168-tooth6510NBSummit Racing$109.95 Powermaster, SBC 168- or 153-tooth9100Summit Racing124.95 Pure Energy, LS starter6489SRock Auto93.99 Mounting a PMGR starter motor in place of the larger, older starters from the '60s and '70s offers a dramatic weight savings, and these smaller starters also offer great starting torque and a much more compact design that will easily clear a set of headers. Plus, they sound cool during cranking. Mounting a PMGR starter motor in place of the larger, older starters from the '60s and '70 When we yanked this starter (rear) off a mid-'80s 305 TBI Camaro, we thought it was a PMGR starter, but it's actually just an undersized starter for smog-era engines. While these starters work, they are neither permanent-magnet nor gear-reduction starters. Note that the attaching bolts are straight across. That indicates its use on a smaller, 153-tooth flywheel. Compare the mounting lugs on the black starter with the PMGR starter (foreground) intended for larger, 168-tooth flywheels using the offset mounting bolt configuration. When we yanked this starter (rear) off a mid-'80s 305 TBI Camaro, we thought it was a PMGR Ever wondered how a gear-reduction planetary system works? With the ring-gear stationary, the four small planetary gears spin clockwise around the sun gear. With a 68-tooth ring gear and a 20-tooth sun gear, the formula is: (Ring/Sun) 1 = gear reduction. As an example, (68/20) 1 = 4.4:1. This means the torque from the starter is multiplied by 4.4:1 (minus frictional losses), creating between 150 lb-ft and upwards of 250 lb-ft of torque. Ever wondered how a gear-reduction planetary system works? With the ring-gear stationary, Here is a Tuff Stuff PMGR starter compared with the standard small-block or big-block starter motor. The weight difference is 9 pounds for the PMGR starter and 16 pounds for the standard starter. Here is a Tuff Stuff PMGR starter compared with the standard small-block or big-block star Powermaster's PN 91000 small-block Chevy PMGR starter has steel planetary gears, offers a clockable mounting block for header clearance, and weighs a mere 8 pounds. With the two sets of mounting holes, this starter can be used on either 153- or 168-tooth flywheels. Powermaster includes a starter dyno sheet with each unit. Maximum torque from this starter is 7.6 lb-ft. Multiply that by the ratio of the starter to the 168-tooth flywheel with 10 teeth on the starter, and the starter applies roughly 127 lb-ft of torque to the crank. Powermaster's PN 91000 small-block Chevy PMGR starter has steel planetary gears, offers a All late-model Ford Mod engines and GM LS engines now use PMGR starters. This unit is a Pure Energy starter from Rock Auto for a budget 5.3L truck engine we're bolting in our Orange Peel Chevelle, as our swap-meet engine didn't come with a starter. All late-model Ford Mod engines and GM LS engines now use PMGR starters. This unit is a Pu By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!