Boundary Billet Oil Pump Gears for D16A/D16Z6

Boundary High Flow Billet Oil Pump Gears - Honda D16 (P29 Pump Only)

These are the PM7-style high flow gears for the D16, and they do two jobs at once. They move more oil than the factory gears, and they're cut from billet steel that's roughly 18 times stronger than the sintered powdered metal Honda used. If you're building a D16 that revs, or one that's picked up boost or nitrous along the way, this is one of the cheapest ways to make sure the oiling system isn't what lets go.

Read This First: P29 Pump Only

Check this before you order, because it's easy to get wrong. These gears fit the P29 pump only. Honda used more than one pump across D-series engines, and knowing you've got a D16A1, D16A8, or D16A9 doesn't tell you which pump is bolted to it, particularly on engines that have been swapped, rebuilt, or pieced together over the decades.

Pull your pump or confirm the casting before ordering. If you're not sure what you're looking at, get in touch and we'll help you identify it. Better a quick check now than the wrong gears in hand with the engine apart.

High Flow, Not Just Stronger

The PM7-style design moves more oil than the factory gear set, which matters when you've built the engine past what Honda planned for. More power and more rpm mean more oil demand, both for lubrication and for carrying heat out of the bearings. A stock-flow pump on a built motor is running closer to its limit than most people realize.

Billet Steel Versus Sintered Powdered Metal

The strength difference is the other half. Honda sinters their pump gears because it's a cost-efficient process with tight tolerances, but sintered powdered steel is weaker than a casting, around 6,000 PSI. Boundary uses solid billet steel approaching 110,000 PSI yield strength and cuts every tooth in-house, roughly 18 times stronger in the raw material alone. The steel grade and heat treat were developed with metallurgists, and each gear carries an HT number traceable to its original material spec sheet.

MartenWear Dual-Stage Heat Treat

These carry Boundary's MartenWear dual-stage heat treatment, rated for operation over 9,000 RPM. D-series builds routinely see rpm the factory never intended, and that rating is what separates a gear that survives it from one that eventually cracks. Dual-stage gets you a hard wearing surface with a tough core, so it resists wear without turning brittle.

Flow-Tested And Backed For Life

Boundary validates every design on their own flow bench to 12,000 RPM before it ships, and they hold two US patents on their pump designs. Machined in the USA and covered by a lifetime warranty.

Fitment

These gears fit the Honda D16A1, D16A8, and D16A9 using the P29 pump. Confirm your pump before ordering.

Who Should Run These Gears

This is for the D-series builder who's making real power out of a small engine and knows the oiling system has to keep up. High compression, high rpm, boost, or nitrous, they all put more demand on the pump than a stock D16 ever saw. Confirm you're running a P29 pump, get these in while it's apart, and stop worrying about it.

Fits: Honda D16A1, D16A8, and D16A9 with the P29 pump only. Part number: P29-OPG-M. Type: PM7-style high flow. Material: billet steel, approximately 110,000 PSI yield strength versus roughly 6,000 PSI for OEM sintered gears. Heat treat: MartenWear dual-stage, rated for operation over 9,000 RPM. Testing: flow-tested to 12,000 RPM. Warranty: lifetime. Made in the USA.