DRIVE SYSTEM

PSI started making drive snouts, pulleys, and crank hubs to resolve snout failures, blower belts breaking, crank hubs galling, and bottom pulleys falling off.

Snouts

PSI blower snouts consist of three components sold separately: The snout, which attached to the blower gearcase, a drive flange, which attaches to the rotor, and a coupler. For 206 series screw blowers, the coupler is a quill shaft. This quill shaft isolates the naturally jerky crankshaft motion from the smooth rotation of the blower. This is easier on the belt and reduces crank hub galling.

The quill shaft snouts have a couple of other advantages:

• Oil circulation holes between the front bearing and the seal forces lubrication into the bearings from the blower lube system.
• Snouts accept a 24-tooth 14mm pulley without modification.
• Special 1600 snout even allows pulleys as small as 32 tooth 8mm. This makes possible the use of a 1600 tooth 8mm belt, which has a greatly increase belt life.

Pulleys::

PSI's pulleys have a number of advantages over the competition:

The bottom pulleys have a dished web, which meets the outside of the pulley at midspan. This makes them stiffer, therby increasing belt life, without adding weight or affecting interchangeability

To avoid the common problem of cumulative error in the cutting of pulley teeth, PSI's manufacturing process assures that the pulley teeth are always perfectly positioned to mate with the teeth on the belt. This maximizes the number of teeth making contact at one time, which lengthens belt life.

Idler Pulleys:

For customers who are experiencing belts fraying or shredding from the sides, we recommend one of our idler pulleys. They are crowned, which coaxes the belt to ride in the center of the pulley, and the flanges are contoured to avoid contacting the kevlar. We make three sizes to accommodate different manifold and black heights; you can also specify whether you have a 5/8" or 3/4" bolt through the mounting flanges.

Bottom Pulley Clamp

It’s not uncommon to see a drag race lost when a bottom pulley falls off during the run.
The problem is loose or broken bottom pulley bolts. The PSI solution is to augment the clamping force of the six small bolts. This cone-shaped device contains a large center bolt that transmits 40,000 pounds of force through the pulley into the crankshaft.

Crank Hubs

PSI’s crank hubs are designed to prevent galling. The PSI titanium crank hub design includes a high-strength bronze washer that acts like a bearing between the surfaces. Removing our titanium crank hub from the crank requires only a 3/8" ratchet wrench operating a small puller.

The keyways are broached on center,180 degrees apart and parallel to the bore within exacting tolerances. This extremely accurate machining reduces backlash.

Crank Keys

Because commercially available key stock is too weak for high performance applications, PSI makes crank keys of heat treated S7 tool steel and grinds them accurately. Designed specifically for racing, they are significantly harder without sacrificing toughness. You can bend them ninety degrees and they don’t shatter.

Degree Wheels

PSI makes three "crank-trigger" styles (radial, inboard support, and standard), and one non-crank-trigger style. All are black anodized with engraved degree markings for improved visibility of the lines while setting your ignition. The timing marks are in one, five and ten degree increments; the 90-degree increments are omitted so you can find the group that matches with your particular pointer and scribe it yourself. An added feature is that all PSI degree wheels attach to the crank hub with a double bolt and pin pattern. This allows you to rotate the degree wheel to realign it if you switch crankshaft brands.



Inboard Support Crank Hub

PSI introduced a Top Fuel version of both our crank hub and crank trigger degree wheel. Racers using the inboard-style crank support in Top Fuel and Funny Car were experiencing galling. The crank hub would split and weld itself to the cam drive gear. PSI’s solution is to integrate the inner face of the roller bearing into the crank hub. The increased wall thickness eliminates the splitting problem and the unique heat treatment process prevents it from galling to the crankshaft.

The inboard support degree wheel fits on this crank hub and contains magnets for crank triggering. A nice feature is that it has access holes for the support housing bolts. It specifically is not lightened with ribs to prevent early failures.



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