Progear Brand True Double Roller W/ Hardened Gears. 2º Increments
We are surprised at how many brands are out there selling so called "high performance
timing sets" with crankshaft sprockets that not even hardened. Some are just virgin steel
and some have the appearance of being heat treated, but are not actually hardened.
Some are powdered metal.
Progear crankshaft sprockets are made from 1141 steel and are all hardened to 50 Rc. But we wanted to be better. On the 3000 and 4000 series not only is the crank sprocket hardened, the camshaft sprocket is heat treated as well.
We also saw that the other sprockets being sold were full of razor sharp edges. Viewed through a jeweler's loupe these sprockets are full of hanging burrs, many of which will end up in the oil pump. All Progear sprockets are vibratory tumbled. All steel sprockets are hand filed and then vibratory tumbled twice--once before heat treat and again after heat treat. This knocks off any hanging burrs, eliminates sharp edges and removes heat treat scale. It also peens and work hardens the surfaces for more durability. No other manufacturers that we know of take the time to vibratory finish the sprockets. Only Progear.
How often have you removed a timing chain cover after a short run time only to find the timing chain already loose? If you are like most of us, too many times. Can't anyone make a timing chain that doesn't stretch? Well...it isn't the chain!! At least it isn't the chain to start with. The reason the chain is loose is because the gears are soft. Even some of the so-called "heat treated" lower sprockets that look like they have been heat treated are soft. Here is the test, try to file the teeth. If you can't file the teeth, the gear is hardened. The soft teeth wear and reshape very quickly creating a different pitch for the chain, forcing it to stretch. ProGear has timing sets with both gears hardened. Test them with a file!
Some oval track racers use gear drives because of the loose chain and sprockets causing retarded timing. Many have gone back to the ProGear 4000 Series and run it an entire season with no wear. These guys have 250lbs seat valve spring pressure, 700lbs open pressure and turn 8000 RPM.