curly

iTrader: (25)

Got a boundary stage one from a customer at work. Upon disassembly, looks like some debris went through it. Unsure if I should be running this, or if a stage one is even the right choice for me. I measured the boundary gears vs. a stock vvt pump, and the VVT gears were ~.050” thicker. Is this the only difference? I’m almost leaning towards running the stock pump with a shim and calling it good or buy a stage 2?

back story: I’m building a forged VVT engine for 250-300hp, stock rev limit.

Turbomack

Those Boundary gears are the stage 1 gears (.373). A stage 2 boundary pump is the high flow pump with bigger gears and the housing machined for higher flow (.430 thickness). The OEM VVT pump (.393) is what the boundary stage 2 was designed to be even better than. From left to right is OEM non VVT, BE Stage 1, BE Stage 2. You need the higher flow for a VVT IMO. BE stage 2 gears are too big for a stock VVT pump housing.

fooger03

iTrader: (2)

That 1/20th of an inch is enough of a gap that the smaller gears will not self-prime on engine start inside the larger housing. (Source: Experience). I imagine the problem is only compounded by the damage to the face of the gears. If you're rebuilding the engine, don't waste your time trying to shim together non-matched parts. Just buy the stage 2 pump.

curly

iTrader: (25)

I would never shim the oil pump gears, I meant the relief valve. From what Travis has told me and what I've read here, sounds like I'm sourcing a S2.

LeoNA

Just make sure you run a factory seal. The information above is how I understand it from my own research. I would not run those used gears they look trashed. If your not running over 7Krpm maybe a OE vvt pump is a good option.